rtiow: add support to send rendering output to https://github.com/Tom94/tev

Add debugging hit DebugHit.
Move some color helpers from mandelbrot to colors mod.
Implement Texture trait for [f32;3]

.gitignore

@@ -1,2 +1,4 @@
 **/target
 **/*.rs.bk
+**/zig-out
+**/zig-cache

README.md

@@ -5,3 +5,5 @@ Raytracers
 
 Random collection of ray tracing experiments.
 
+# TODO
+Implement http://www.kevinbeason.com/smallpt/

rtchallenge/Cargo.lock

@@ -130,7 +130,7 @@ dependencies = [
  "ansi_term",
  "atty",
  "bitflags",
- "strsim",
+ "strsim 0.8.0",
  "textwrap",
  "unicode-width",
  "vec_map",
@@ -259,6 +259,41 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "darling"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f2c43f534ea4b0b049015d00269734195e6d3f0f6635cb692251aca6f9f8b3c"
+dependencies = [
+ "darling_core",
+ "darling_macro",
+]
+
+[[package]]
+name = "darling_core"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e91455b86830a1c21799d94524df0845183fa55bafd9aa137b01c7d1065fa36"
+dependencies = [
+ "fnv",
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim 0.10.0",
+ "syn",
+]
+
+[[package]]
+name = "darling_macro"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29b5acf0dea37a7f66f7b25d2c5e93fd46f8f6968b1a5d7a3e02e97768afc95a"
+dependencies = [
+ "darling_core",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "deflate"
 version = "0.8.6"
@@ -269,6 +304,37 @@ dependencies = [
  "byteorder",
 ]
 
+[[package]]
+name = "derive_builder"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d13202debe11181040ae9063d739fa32cfcaaebe2275fe387703460ae2365b30"
+dependencies = [
+ "derive_builder_macro",
+]
+
+[[package]]
+name = "derive_builder_core"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66e616858f6187ed828df7c64a6d71720d83767a7f19740b2d1b6fe6327b36e5"
+dependencies = [
+ "darling",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "derive_builder_macro"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "58a94ace95092c5acb1e97a7e846b310cfbd499652f72297da7493f618a98d73"
+dependencies = [
+ "derive_builder_core",
+ "syn",
+]
+
 [[package]]
 name = "either"
 version = "1.6.1"
@@ -308,6 +374,12 @@ dependencies = [
  "backtrace",
 ]
 
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
 [[package]]
 name = "getrandom"
 version = "0.2.3"
@@ -349,6 +421,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "ident_case"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
+
 [[package]]
 name = "itertools"
 version = "0.9.0"
@@ -662,6 +740,7 @@ dependencies = [
  "anyhow",
  "core_affinity",
  "criterion",
+ "derive_builder",
  "enum-utils",
  "num_cpus",
  "png",
@@ -773,6 +852,12 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "structopt"
 version = "0.3.22"

rtchallenge/Cargo.toml

@@ -8,13 +8,13 @@ edition = "2018"
 
 [features]
 default = [ "float-as-double" ]
-disable-inverse-cache = []
 float-as-double = []
 
 [dependencies]
 anyhow = "1.0.41"
 core_affinity = "0.5.10"
 criterion = "0.3.4"
+derive_builder = "0.10.2"
 enum-utils = "0.1.2"
 num_cpus = "1.13.0"
 png = "0.16.8"

rtchallenge/examples/balls.rs

@@ -0,0 +1,119 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::{
+    camera::{Camera, RenderStrategy},
+    float::consts::PI,
+    lights::PointLightBuilder,
+    materials::MaterialBuilder,
+    matrices::Matrix4x4,
+    shapes::{Geometry, ShapeBuilder},
+    transformations::view_transform,
+    tuples::Tuple,
+    world::WorldBuilder,
+    Float, WHITE,
+};
+
+/// Experimenting with balls.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "balls")]
+struct Opt {
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+    let width = 2560;
+    let height = 1440;
+
+    let light1 = PointLightBuilder::default()
+        .position(Tuple::point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(Tuple::point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(Tuple::point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let ball_size = 0.5;
+    let num_per_axis = 3;
+    let center_to_center = 4. * ball_size;
+    let from = Tuple::point(
+        -5. * center_to_center,
+        5. * center_to_center,
+        -4. * center_to_center,
+    );
+    let to = Tuple::point(
+        num_per_axis as Float * center_to_center / 2.,
+        0., //num_per_axis as Float * center_to_center / 2.,
+        num_per_axis as Float * center_to_center / 2.,
+    );
+    let up = Tuple::point(0., 1., 0.);
+    let mut camera = Camera::new(width, height, PI / 6.);
+    camera.set_transform(view_transform(from, to, up));
+    camera.render_strategy = opt.render_strategy;
+    camera.samples_per_pixel = opt.samples;
+
+    let floor = ShapeBuilder::default()
+        .geometry(Geometry::Plane)
+        .transform(Matrix4x4::translation(0., -ball_size, 0.))
+        .material(
+            MaterialBuilder::default()
+                .color([0.2, 0.2, 0.2])
+                .specular(0.)
+                .build()?,
+        )
+        .build()?;
+    let mut objects = vec![floor];
+
+    for z in 0..num_per_axis {
+        for y in 0..num_per_axis {
+            for x in 0..num_per_axis {
+                objects.push(
+                    ShapeBuilder::default()
+                        .transform(
+                            Matrix4x4::translation(
+                                x as Float * center_to_center,
+                                y as Float * center_to_center,
+                                z as Float * center_to_center,
+                            ) * Matrix4x4::scaling(ball_size, ball_size, ball_size),
+                        )
+                        .material(
+                            MaterialBuilder::default()
+                                .color([0.1, 1., 0.5])
+                                .ambient(y as Float / 4.)
+                                .diffuse(x as Float / 4.)
+                                .specular(z as Float / 4.)
+                                .build()?,
+                        )
+                        .build()?,
+                );
+            }
+        }
+    }
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(objects)
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/balls.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc10.rs

@@ -0,0 +1,171 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{
+    camera::RenderStrategy,
+    float::consts::PI,
+    patterns::{test_pattern, BLACK_PAT, WHITE_PAT},
+    WHITE,
+};
+
+/// End of chapter 10 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc10")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(2., 2., -10.);
+    let to = point(2., 1., 0.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 4.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(translation(1., 0., 0.) * scaling(2., 2., 2.))
+                        .build()?,
+                )
+                .specular(0.)
+                .build()?,
+        )
+        .build()?;
+    let sphere_size = scaling(0.5, 0.5, 0.5);
+
+    let x1y1 = sphere()
+        .transform(translation(1., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    gradient_pattern([0., 0., 1.].into(), [1., 1., 0.].into())
+                        .transform(scaling(2., 1., 1.) * translation(-0.5, 0., 0.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y1 = sphere()
+        .transform(translation(2., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(stripe_pattern(WHITE_PAT, BLACK_PAT).build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y1 = sphere()
+        .transform(translation(3., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    stripe_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 1., 1.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.0)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2 = sphere()
+        .transform(translation(1., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(test_pattern().build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2 = sphere()
+        .transform(translation(2., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    ring_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 0.2, 0.2))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2 = sphere()
+        .transform(translation(3., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.5, 0.5, 0.5))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(vec![floor, x1y1, x2y1, x3y1, x1y2, x2y2, x3y2])
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc10.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc11.rs

@@ -0,0 +1,218 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{
+    camera::RenderStrategy,
+    float::consts::PI,
+    patterns::{test_pattern, BLACK_PAT, WHITE_PAT},
+    WHITE,
+};
+
+/// End of chapter 11 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc11")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(2., 8., -10.);
+    let to = point(2., 1., -1.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 6.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(
+                        ring_pattern([0.8, 0.8, 0.2].into(), [0.8, 0.2, 0.8].into())
+                            .transform(scaling(1. / 8., 1. / 8., 1. / 8.))
+                            .build()?,
+                        ring_pattern([0.2, 0.8, 0.2].into(), [0.8, 0.2, 0.2].into())
+                            .transform(scaling(1. / 4., 1. / 4., 1. / 4.))
+                            .build()?,
+                    )
+                    .transform(translation(0., 1., 0.) * scaling(2., 2., 2.))
+                    .build()?,
+                )
+                .specular(0.)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+    let sphere_size = scaling(0.5, 0.5, 0.5);
+
+    let x1y1 = sphere()
+        .transform(translation(1., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    gradient_pattern([0., 0., 1.].into(), [1., 1., 0.].into())
+                        .transform(scaling(2., 1., 1.) * translation(-0.5, 0., 0.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y1 = sphere()
+        .transform(translation(2., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(stripe_pattern(WHITE_PAT, BLACK_PAT).build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y1 = sphere()
+        .transform(translation(3., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    stripe_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 1., 1.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.0)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2 = sphere()
+        .transform(translation(1., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(test_pattern().build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2 = sphere()
+        .transform(translation(2., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    ring_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 0.2, 0.2))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2 = sphere()
+        .transform(translation(3., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.5, 0.5, 0.5))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2z1 = sphere()
+        .transform(translation(1., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2z1 = sphere()
+        .transform(translation(2., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.9)
+                .refractive_index(1.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y4z1 = sphere()
+        .transform(translation(2., 4., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.2, 0.2, 0.8])
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(vec![
+            floor, x1y1, x2y1, x3y1, x1y2, x2y2, x3y2, x1y2z1, x2y2z1, x2y4z1,
+        ])
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc11.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc12.rs

@@ -0,0 +1,232 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{
+    camera::RenderStrategy,
+    float::consts::PI,
+    patterns::{test_pattern, BLACK_PAT, WHITE_PAT},
+    WHITE,
+};
+
+/// End of chapter 12 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc12")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(2., 8., -10.);
+    let to = point(2., 1., -1.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 6.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(
+                        ring_pattern([0.8, 0.8, 0.2].into(), [0.8, 0.2, 0.8].into())
+                            .transform(scaling(1. / 8., 1. / 8., 1. / 8.))
+                            .build()?,
+                        ring_pattern([0.2, 0.8, 0.2].into(), [0.8, 0.2, 0.2].into())
+                            .transform(scaling(1. / 4., 1. / 4., 1. / 4.))
+                            .build()?,
+                    )
+                    .transform(translation(0., 1., 0.) * scaling(2., 2., 2.))
+                    .build()?,
+                )
+                .specular(0.)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+    let sphere_size = scaling(0.5, 0.5, 0.5);
+
+    let x1y1 = sphere()
+        .transform(translation(1., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    gradient_pattern([0., 0., 1.].into(), [1., 1., 0.].into())
+                        .transform(scaling(2., 1., 1.) * translation(-0.5, 0., 0.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y1 = sphere()
+        .transform(translation(2., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(stripe_pattern(WHITE_PAT, BLACK_PAT).build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y1 = sphere()
+        .transform(translation(3., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    stripe_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 1., 1.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.0)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2 = sphere()
+        .transform(translation(1., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(test_pattern().build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2 = sphere()
+        .transform(translation(2., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    ring_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 0.2, 0.2))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2 = sphere()
+        .transform(translation(3., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.5, 0.5, 0.5))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2z1 = sphere()
+        .transform(translation(1., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2z1 = sphere()
+        .transform(translation(2., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.9)
+                .refractive_index(1.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2z1 = cube()
+        .transform(
+            translation(3., 2., -1.) * (sphere_size * scaling(0.5, 0.5, 0.5)) * rotation_y(PI / 4.),
+        )
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.8, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y4z1 = sphere()
+        .transform(translation(2., 4., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.2, 0.2, 0.8])
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(vec![
+            floor, x1y1, x2y1, x3y1, x1y2, x2y2, x3y2, x1y2z1, x2y2z1, x2y4z1, x3y2z1,
+        ])
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc12.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc14.rs

@@ -0,0 +1,232 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{
+    camera::RenderStrategy,
+    float::consts::PI,
+    patterns::{test_pattern, BLACK_PAT, WHITE_PAT},
+    WHITE,
+};
+
+/// End of chapter 14 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc14")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(2., 8., -10.);
+    let to = point(2., 2., -1.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 12.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(
+                        ring_pattern([0.8, 0.8, 0.2].into(), [0.8, 0.2, 0.8].into())
+                            .transform(scaling(1. / 8., 1. / 8., 1. / 8.))
+                            .build()?,
+                        ring_pattern([0.2, 0.8, 0.2].into(), [0.8, 0.2, 0.2].into())
+                            .transform(scaling(1. / 4., 1. / 4., 1. / 4.))
+                            .build()?,
+                    )
+                    .transform(translation(0., 1., 0.) * scaling(2., 2., 2.))
+                    .build()?,
+                )
+                .specular(0.)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+    let sphere_size = scaling(0.5, 0.5, 0.5);
+
+    let x1y1 = sphere()
+        .transform(translation(1., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    gradient_pattern([0., 0., 1.].into(), [1., 1., 0.].into())
+                        .transform(scaling(2., 1., 1.) * translation(-0.5, 0., 0.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y1 = sphere()
+        .transform(translation(2., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(stripe_pattern(WHITE_PAT, BLACK_PAT).build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y1 = sphere()
+        .transform(translation(3., 1., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    stripe_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 1., 1.))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.0)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2 = sphere()
+        .transform(translation(1., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(test_pattern().build()?)
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2 = sphere()
+        .transform(translation(2., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    ring_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.2, 0.2, 0.2))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2 = sphere()
+        .transform(translation(3., 2., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color(
+                    checkers_pattern(WHITE_PAT, BLACK_PAT)
+                        .transform(scaling(0.5, 0.5, 0.5))
+                        .build()?,
+                )
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let x1y2z1 = sphere()
+        .transform(translation(1., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y2z1 = sphere()
+        .transform(translation(2., 2., -1.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.2, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .transparency(0.9)
+                .refractive_index(1.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x3y2z1 = cube()
+        .transform(
+            translation(3., 2., -1.) * (sphere_size * scaling(0.5, 0.5, 0.5)) * rotation_y(PI / 4.),
+        )
+        .material(
+            MaterialBuilder::default()
+                .color([0.8, 0.8, 0.2])
+                .diffuse(0.7)
+                .specular(0.3)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+
+    let x2y4z1 = sphere()
+        .transform(translation(2., 4., 0.) * sphere_size)
+        .material(
+            MaterialBuilder::default()
+                .color([0.2, 0.2, 0.8])
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(vec![
+            floor, x1y1, x2y1, x3y1, x1y2, x2y2, x3y2, x1y2z1, x2y2z1, x2y4z1, x3y2z1,
+        ])
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc14.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc6.rs

@@ -22,7 +22,7 @@ fn main() -> Result<()> {
     let half = wall_size / 2.;
     let mut shape = Shape::sphere();
     shape.material = Material {
-        color: Color::new(1., 0.2, 1.),
+        color: Color::new(1., 0.2, 1.).into(),
         specular: 0.5,
         diffuse: 0.7,
         shininess: 30.,
@@ -44,7 +44,15 @@ fn main() -> Result<()> {
                 let point = r.position(hit.t);
                 let normal = hit.object.normal_at(point);
                 let eye = -r.direction;
-                let color = lighting(&hit.object.material, &light, point, eye, normal, in_shadow);
+                let color = lighting(
+                    &hit.object.material,
+                    &hit.object,
+                    &light,
+                    point,
+                    eye,
+                    normal,
+                    in_shadow,
+                );
                 c.set(x, y, color);
             }
         }

rtchallenge/examples/eoc7.rs

@@ -42,7 +42,7 @@ fn main() -> Result<()> {
     let mut floor = Shape::sphere();
     floor.set_transform(Matrix4x4::scaling(10., 0.01, 10.));
     floor.material = Material {
-        color: Color::new(1., 0.9, 0.9),
+        color: Color::new(1., 0.9, 0.9).into(),
         specular: 0.,
         ..Material::default()
     };
@@ -68,7 +68,7 @@ fn main() -> Result<()> {
     let mut middle = Shape::sphere();
     middle.set_transform(Matrix4x4::translation(-0.5, 1., 0.5));
     middle.material = Material {
-        color: Color::new(0.1, 1., 0.5),
+        color: Color::new(0.1, 1., 0.5).into(),
         diffuse: 0.7,
         specular: 0.3,
         ..Material::default()
@@ -77,7 +77,7 @@ fn main() -> Result<()> {
     let mut right = Shape::sphere();
     right.set_transform(Matrix4x4::translation(1.5, 0.5, -0.5) * Matrix4x4::scaling(0.5, 0.5, 0.5));
     right.material = Material {
-        color: Color::new(0.5, 1., 0.1),
+        color: Color::new(0.5, 1., 0.1).into(),
         diffuse: 0.7,
         specular: 0.3,
         ..Material::default()
@@ -88,7 +88,7 @@ fn main() -> Result<()> {
         Matrix4x4::translation(-1.5, 0.33, -0.75) * Matrix4x4::scaling(0.33, 0.33, 0.33),
     );
     left.material = Material {
-        color: Color::new(1., 0.8, 0.1),
+        color: Color::new(1., 0.8, 0.1).into(),
         diffuse: 0.7,
         specular: 0.3,
         ..Material::default()

rtchallenge/examples/eoc8.rs

@@ -54,7 +54,7 @@ fn main() -> Result<()> {
     let mut floor = Shape::sphere();
     floor.set_transform(Matrix4x4::scaling(10., 0.01, 10.));
     floor.material = Material {
-        color: Color::new(1., 0.9, 0.9),
+        color: Color::new(1., 0.9, 0.9).into(),
         specular: 0.,
         ..Material::default()
     };
@@ -80,7 +80,7 @@ fn main() -> Result<()> {
     let mut middle = Shape::sphere();
     middle.set_transform(Matrix4x4::translation(-0.5, 1., 0.5));
     middle.material = Material {
-        color: Color::new(0.1, 1., 0.5),
+        color: Color::new(0.1, 1., 0.5).into(),
         diffuse: 0.7,
         specular: 0.3,
         ..Material::default()
@@ -89,7 +89,7 @@ fn main() -> Result<()> {
     let mut right = Shape::sphere();
     right.set_transform(Matrix4x4::translation(1.5, 0.5, -0.5) * Matrix4x4::scaling(0.5, 0.5, 0.5));
     right.material = Material {
-        color: Color::new(1., 1., 1.),
+        color: Color::new(1., 1., 1.).into(),
         diffuse: 0.7,
         specular: 0.0,
         ..Material::default()
@@ -100,7 +100,7 @@ fn main() -> Result<()> {
         Matrix4x4::translation(-1.5, 0.33, -0.75) * Matrix4x4::scaling(0.33, 0.33, 0.33),
     );
     left.material = Material {
-        color: Color::new(1., 0.8, 0.1),
+        color: Color::new(1., 0.8, 0.1).into(),
         diffuse: 0.7,
         specular: 0.3,
         ..Material::default()

rtchallenge/examples/eoc9-prelude.rs

@@ -0,0 +1,122 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{camera::RenderStrategy, float::consts::PI, WHITE};
+
+/// End of chapter 9 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc9")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(0., 1.5, -5.);
+    let to = point(0., 1., 0.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 4.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .material(
+            MaterialBuilder::default()
+                .color([1., 0.2, 0.2])
+                .specular(0.)
+                .build()?,
+        )
+        .build()?;
+
+    let ceiling = plane()
+        .transform(translation(0., 6., 0.) * rotation_x(PI))
+        .material(
+            MaterialBuilder::default()
+                .color([0.6, 0.6, 0.8])
+                .specular(0.2)
+                .build()?,
+        )
+        .build()?;
+
+    let middle = sphere()
+        .transform(translation(-0.5, 0.5, 0.5))
+        .material(
+            MaterialBuilder::default()
+                .color([0.1, 1., 0.5])
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let right = sphere()
+        .transform(translation(1.5, 0.5, -0.5) * scaling(0.5, 0.5, 0.5))
+        .material(
+            MaterialBuilder::default()
+                .color([1., 1., 1.])
+                .diffuse(0.7)
+                .specular(0.0)
+                .build()?,
+        )
+        .build()?;
+
+    let left = sphere()
+        .transform(translation(-1.5, 0.33, -0.75) * scaling(0.33, 0.33, 0.33))
+        .material(
+            MaterialBuilder::default()
+                .color([1., 0.8, 0.1])
+                .diffuse(0.7)
+                .specular(0.3)
+                .build()?,
+        )
+        .build()?;
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(vec![floor, ceiling, middle, right, left])
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc9.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/eoc9.rs

@@ -0,0 +1,114 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::{
+    camera::{Camera, RenderStrategy},
+    float::consts::PI,
+    lights::PointLight,
+    materials::Material,
+    matrices::Matrix4x4,
+    shapes::Shape,
+    transformations::view_transform,
+    tuples::{Color, Tuple},
+    world::World,
+    WHITE,
+};
+
+/// End of chapter 9 challenge.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "eoc9")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light_position = Tuple::point(-5., 5., -5.);
+    let light_color = WHITE;
+    let light1 = PointLight::new(light_position, light_color);
+    let light_position = Tuple::point(5., 5., -5.);
+    let light_color = Color::new(0.2, 0.2, 0.6);
+    let light2 = PointLight::new(light_position, light_color);
+    let light_position = Tuple::point(0., 2., -5.);
+    let light_color = Color::new(0.2, 0.2, 0.1);
+    let light3 = PointLight::new(light_position, light_color);
+
+    let mut camera = Camera::new(opt.width, opt.height, PI / 4.);
+    let from = Tuple::point(0., 1.5, -5.);
+    let to = Tuple::point(0., 1., 0.);
+    let up = Tuple::point(0., 1., 0.);
+    camera.set_transform(view_transform(from, to, up));
+    camera.render_strategy = opt.render_strategy;
+    camera.samples_per_pixel = opt.samples;
+
+    let mut floor = Shape::plane();
+    floor.material = Material {
+        color: Color::new(1., 0.2, 0.2).into(),
+        specular: 0.,
+        ..Material::default()
+    };
+    let mut ceiling = Shape::plane();
+    ceiling.set_transform(Matrix4x4::translation(0., 6., 0.) * Matrix4x4::rotation_x(PI));
+    ceiling.material = Material {
+        color: Color::new(0.6, 0.6, 0.8).into(),
+        specular: 0.2,
+        ..Material::default()
+    };
+
+    let mut middle = Shape::sphere();
+    middle.set_transform(Matrix4x4::translation(-0.5, 0.5, 0.5));
+    middle.material = Material {
+        color: Color::new(0.1, 1., 0.5).into(),
+        diffuse: 0.7,
+        specular: 0.3,
+        ..Material::default()
+    };
+
+    let mut right = Shape::sphere();
+    right.set_transform(Matrix4x4::translation(1.5, 0.5, -0.5) * Matrix4x4::scaling(0.5, 0.5, 0.5));
+    right.material = Material {
+        color: Color::new(1., 1., 1.).into(),
+        diffuse: 0.7,
+        specular: 0.0,
+        ..Material::default()
+    };
+
+    let mut left = Shape::sphere();
+    left.set_transform(
+        Matrix4x4::translation(-1.5, 0.33, -0.75) * Matrix4x4::scaling(0.33, 0.33, 0.33),
+    );
+    left.material = Material {
+        color: Color::new(1., 0.8, 0.1).into(),
+        diffuse: 0.7,
+        specular: 0.3,
+        ..Material::default()
+    };
+
+    let mut world = World::default();
+    world.lights = vec![light1, light2, light3];
+    world.objects = vec![floor, ceiling, middle, right, left];
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/eoc9.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/examples/glass.rs

@@ -0,0 +1,115 @@
+use std::time::Instant;
+
+use anyhow::Result;
+use structopt::StructOpt;
+
+use rtchallenge::prelude::*;
+
+use rtchallenge::{
+    camera::RenderStrategy,
+    float::consts::PI,
+    patterns::{BLACK_PAT, WHITE_PAT},
+    WHITE,
+};
+
+/// Experiment with transparency.
+#[derive(StructOpt, Debug)]
+#[structopt(name = "glass")]
+struct Opt {
+    /// Strategy for casting rays into image.
+    #[structopt(long, default_value = "rayon")]
+    render_strategy: RenderStrategy,
+    /// Number of samples per pixel.  0 renders from the center of the pixel, 1 or more samples N
+    /// times randomly across the pixel.
+    #[structopt(short, long, default_value = "0")]
+    samples: usize,
+    /// Rendered image width in pixels.
+    #[structopt(short, long, default_value = "2560")]
+    width: usize,
+    /// Rendered image height in pixels.
+    #[structopt(short, long, default_value = "1440")]
+    height: usize,
+}
+
+fn main() -> Result<()> {
+    let start = Instant::now();
+    let opt = Opt::from_args();
+
+    let light1 = PointLightBuilder::default()
+        .position(point(-5., 5., -5.))
+        .intensity(WHITE)
+        .build()?;
+    let light2 = PointLightBuilder::default()
+        .position(point(5., 5., -5.))
+        .intensity([0.2, 0.2, 0.6])
+        .build()?;
+    let light3 = PointLightBuilder::default()
+        .position(point(0., 2., -5.))
+        .intensity([0.2, 0.2, 0.1])
+        .build()?;
+
+    let from = point(0., 0., -10.);
+    let to = point(0., 0., 0.);
+    let up = point(0., 1., 0.);
+    let camera = CameraBuilder::default()
+        .hsize(opt.width)
+        .vsize(opt.height)
+        .field_of_view(PI / 4.)
+        .transform(view_transform(from, to, up))
+        .render_strategy(opt.render_strategy)
+        .samples_per_pixel(opt.samples)
+        .build()?;
+
+    let floor = plane()
+        .transform(rotation_x(PI / 2.))
+        .material(
+            MaterialBuilder::default()
+                .color(checkers_pattern(BLACK_PAT, WHITE_PAT).build()?)
+                .reflective(0.5)
+                .build()?,
+        )
+        .build()?;
+    let ceiling = plane()
+        .transform(translation(0., 0., -20.) * rotation_x(PI / 2.))
+        .material(MaterialBuilder::default().color([0.2, 0.2, 0.8]).build()?)
+        .build()?;
+
+    let mut objects = Vec::new();
+    for x in 0..5 {
+        for y in 0..5 {
+            let trans = y as Float / 5.;
+            let index = 1. + x as Float / 5.;
+            dbg!(x, y, trans, index);
+            objects.push(
+                sphere()
+                    .transform(
+                        translation(x as Float - 2., y as Float - 2., -2.) * scaling(0.5, 0.5, 0.5),
+                    )
+                    .material(
+                        MaterialBuilder::default()
+                            .color([0.5, 0.5, 0.5])
+                            .transparency(trans)
+                            .refractive_index(index)
+                            .build()?,
+                    )
+                    .build()?,
+            );
+        }
+    }
+
+    objects.push(floor);
+    objects.push(ceiling);
+
+    let world = WorldBuilder::default()
+        .lights(vec![light1, light2, light3])
+        .objects(objects)
+        .build()?;
+
+    let image = camera.render(&world);
+
+    let path = "/tmp/glass.png";
+    println!("saving output to {}", path);
+    image.write_to_file(path)?;
+    println!("Render time {:.3} seconds", start.elapsed().as_secs_f32());
+    Ok(())
+}

rtchallenge/rustfmt.toml

@@ -1 +1,2 @@
+imports_granularity = "Crate"
 format_code_in_doc_comments = true

rtchallenge/src/camera.rs

@@ -2,11 +2,12 @@ use std::{
     str::FromStr,
     sync::{
         mpsc::{sync_channel, Receiver, SyncSender},
-        {Arc, Mutex},
+        Arc, Mutex,
     },
     thread,
 };
 
+use derive_builder::Builder;
 use rand::Rng;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use serde::Deserialize;
@@ -21,6 +22,8 @@ use crate::{
     Float, BLACK,
 };
 
+const MAX_DEPTH_RECURSION: usize = 10;
+
 #[derive(Copy, Clone, StructOpt, Debug, Deserialize)]
 #[serde(rename_all = "kebab-case")]
 pub enum RenderStrategy {
@@ -28,28 +31,82 @@ pub enum RenderStrategy {
     Rayon,
     WorkerPool,
 }
-impl FromStr for RenderStrategy {
+
-    type Err = serde_json::error::Error;
+impl Default for RenderStrategy {
-    fn from_str(s: &str) -> Result<RenderStrategy, serde_json::error::Error> {
+    fn default() -> RenderStrategy {
-        Ok(serde_json::from_str(&format!("\"{}\"", s))?)
+        RenderStrategy::Rayon
     }
 }
 
-#[derive(Clone)]
+impl FromStr for RenderStrategy {
+    type Err = serde_json::error::Error;
+    fn from_str(s: &str) -> Result<RenderStrategy, serde_json::error::Error> {
+        serde_json::from_str(&format!("\"{}\"", s))
+    }
+}
+
+#[derive(Builder, Clone, Debug, Default)]
+#[builder(setter(skip), build_fn(skip))]
 pub struct Camera {
+    #[builder(setter(skip = "false"))]
     hsize: usize,
+    #[builder(setter(skip = "false"))]
     vsize: usize,
+    #[builder(setter(skip = "false"))]
     field_of_view: Float,
+    #[builder(setter(skip = "false"))]
     transform: Matrix4x4,
     inverse_transform: Matrix4x4,
     pixel_size: Float,
     half_width: Float,
     half_height: Float,
+    #[builder(setter(skip = "false"))]
     pub render_strategy: RenderStrategy,
     /// 0 renders from the center of the pixel, 1 or higher is random sampling of the pixel.
+    #[builder(setter(skip = "false"))]
     pub samples_per_pixel: usize,
 }
 
+impl CameraBuilder {
+    pub fn build(&self) -> Result<Camera, CameraBuilderError> {
+        let hsize = match self.hsize {
+            Some(ref value) => Clone::clone(value),
+            None => {
+                return Err(Into::into(::derive_builder::UninitializedFieldError::from(
+                    "hsize",
+                )))
+            }
+        };
+        let vsize = match self.vsize {
+            Some(ref value) => Clone::clone(value),
+            None => {
+                return Err(Into::into(::derive_builder::UninitializedFieldError::from(
+                    "vsize",
+                )))
+            }
+        };
+        let field_of_view = match self.field_of_view {
+            Some(ref value) => Clone::clone(value),
+            None => {
+                return Err(Into::into(::derive_builder::UninitializedFieldError::from(
+                    "field_of_view",
+                )))
+            }
+        };
+        let mut c = Camera::new(hsize, vsize, field_of_view);
+        if let Some(transform) = self.transform {
+            c.set_transform(transform);
+        }
+        if let Some(render_strategy) = self.render_strategy {
+            c.render_strategy = render_strategy;
+        }
+        if let Some(samples_per_pixel) = self.samples_per_pixel {
+            c.samples_per_pixel = samples_per_pixel;
+        }
+        Ok(c)
+    }
+}
+
 enum Request {
     Line { width: usize, y: usize },
 }
@@ -61,27 +118,6 @@ enum Response {
 impl Camera {
     /// Create a camera with a canvas of pixel hsize (height) and vsize (width)
     /// with the given field of view (in radians).
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{camera::Camera, float::consts::PI, matrices::Matrix4x4, EPSILON};
-    ///
-    /// let hsize = 160;
-    /// let vsize = 120;
-    /// let field_of_view = PI / 2.;
-    /// let c = Camera::new(hsize, vsize, field_of_view);
-    /// assert_eq!(c.hsize(), 160);
-    /// assert_eq!(c.vsize(), 120);
-    /// assert_eq!(c.transform(), Matrix4x4::identity());
-    ///
-    /// // Pixel size for a horizontal canvas.
-    /// let c = Camera::new(200, 150, PI / 2.);
-    /// assert!((c.pixel_size() - 0.010).abs() < EPSILON);
-    ///
-    /// // Pixel size for a horizontal canvas.
-    /// let c = Camera::new(150, 200, PI / 2.);
-    /// assert!((c.pixel_size() - 0.010).abs() < EPSILON);
-    /// ```
     pub fn new(hsize: usize, vsize: usize, field_of_view: Float) -> Camera {
         let half_view = (field_of_view / 2.).tan();
         let aspect = hsize as Float / vsize as Float;
@@ -151,47 +187,17 @@ impl Camera {
 
     /// Calculate ray that starts at the camera and passes through the (x,y)
     /// pixel on the canvas.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{
-    ///     camera::Camera, float::consts::PI, matrices::Matrix4x4, tuples::Tuple, Float,
-    /// };
-    ///
-    /// // Constructing a ray through the center of the canvas.
-    /// let c = Camera::new(201, 101, PI / 2.);
-    /// let r = c.ray_for_pixel(100, 50);
-    /// assert_eq!(r.origin, Tuple::point(0., 0., 0.));
-    /// assert_eq!(r.direction, Tuple::vector(0., 0., -1.));
-    ///
-    /// // Constructing a ray through the corner of the canvas.
-    /// let c = Camera::new(201, 101, PI / 2.);
-    /// let r = c.ray_for_pixel(0, 0);
-    /// assert_eq!(r.origin, Tuple::point(0., 0., 0.));
-    /// assert_eq!(r.direction, Tuple::vector(0.66519, 0.33259, -0.66851));
-    ///
-    /// // Constructing a ray when the camera is transformed.
-    /// let mut c = Camera::new(201, 101, PI / 2.);
-    /// c.set_transform(Matrix4x4::rotation_y(PI / 4.) * Matrix4x4::translation(0., -2., 5.));
-    /// let r = c.ray_for_pixel(100, 50);
-    /// assert_eq!(r.origin, Tuple::point(0., 2., -5.));
-    /// assert_eq!(
-    ///     r.direction,
-    ///     Tuple::vector((2. as Float).sqrt() / 2., 0., -(2. as Float).sqrt() / 2.)
-    /// );
-    /// ```
-    #[cfg(not(feature = "disable-inverse-cache"))]
     pub fn ray_for_pixel(&self, px: usize, py: usize) -> Ray {
         // The offset from the edge of the canvas to the pixel's corner.
         let xoffset = (px as Float + 0.5) * self.pixel_size;
         let yoffset = (py as Float + 0.5) * self.pixel_size;
 
-        // The untransformed coordinates of the pixle in world space.
+        // The untransformed coordinates of the pixel in world space.
         // (Remember that the camera looks toward -z, so +x is to the left.)
         let world_x = self.half_width - xoffset;
         let world_y = self.half_height - yoffset;
 
-        // Using the camera matrix, transofmrm the canvas point and the origin,
+        // Using the camera matrix, transform the canvas point and the origin,
         // and then compute the ray's direction vector.
         // (Remember that the canvas is at z>=-1).
         let pixel = self.inverse_transform * Tuple::point(world_x, world_y, -1.);
@@ -200,48 +206,8 @@ impl Camera {
 
         Ray::new(origin, direction)
     }
-    #[cfg(feature = "disable-inverse-cache")]
-    pub fn ray_for_pixel(&self, px: usize, py: usize) -> Ray {
-        // The offset from the edge of the canvas to the pixel's corner.
-        let xoffset = (px as Float + 0.5) * self.pixel_size;
-        let yoffset = (py as Float + 0.5) * self.pixel_size;
-
-        // The untransformed coordinates of the pixle in world space.
-        // (Remember that the camera looks toward -z, so +x is to the left.)
-        let world_x = self.half_width - xoffset;
-        let world_y = self.half_height - yoffset;
-
-        // Using the camera matrix, transofmrm the canvas point and the origin,
-        // and then compute the ray's direction vector.
-        // (Remember that the canvas is at z>=-1).
-        let pixel = self.transform.inverse() * Tuple::point(world_x, world_y, -1.);
-        let origin = self.transform.inverse() * Tuple::point(0., 0., 0.);
-        let direction = (pixel - origin).normalize();
-
-        Ray::new(origin, direction)
-    }
 
     /// Use camera to render an image of the given world.
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{
-    ///     camera::Camera,
-    ///     float::consts::PI,
-    ///     transformations::view_transform,
-    ///     tuples::{Color, Tuple},
-    ///     world::World,
-    /// };
-    ///
-    /// // Rendering a world with a camera.
-    /// let w = World::test_world();
-    /// let mut c = Camera::new(11, 11, PI / 2.);
-    /// let from = Tuple::point(0., 0., -5.);
-    /// let to = Tuple::point(0., 0., 0.);
-    /// let up = Tuple::vector(0., 1., 0.);
-    /// c.set_transform(view_transform(from, to, up));
-    /// let image = c.render(&w);
-    /// assert_eq!(image.get(5, 5), Color::new(0.38066, 0.47583, 0.2855));
-    /// ```
     pub fn render(&self, w: &World) -> Canvas {
         use RenderStrategy::*;
 
@@ -361,12 +327,12 @@ impl Camera {
             let color = self
                 .supersample_rays_for_pixel(x, y, self.samples_per_pixel)
                 .iter()
-                .map(|ray| w.color_at(&ray))
+                .map(|ray| w.color_at(ray, MAX_DEPTH_RECURSION))
                 .fold(BLACK, |acc, c| acc + c);
             color / self.samples_per_pixel as Float
         } else {
             let ray = self.ray_for_pixel(x, y);
-            w.color_at(&ray)
+            w.color_at(&ray, MAX_DEPTH_RECURSION)
         }
     }
 }
@@ -401,3 +367,70 @@ fn render_worker_task(
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        camera::Camera,
+        float::consts::PI,
+        matrices::Matrix4x4,
+        transformations::view_transform,
+        tuples::{point, vector},
+        world::World,
+        Float, EPSILON,
+    };
+    #[test]
+    fn new() {
+        let hsize = 160;
+        let vsize = 120;
+        let field_of_view = PI / 2.;
+        let c = Camera::new(hsize, vsize, field_of_view);
+        assert_eq!(c.hsize(), 160);
+        assert_eq!(c.vsize(), 120);
+        assert_eq!(c.transform(), Matrix4x4::identity());
+
+        // Pixel size for a horizontal canvas.
+        let c = Camera::new(200, 150, PI / 2.);
+        assert!((c.pixel_size() - 0.010).abs() < EPSILON);
+
+        // Pixel size for a horizontal canvas.
+        let c = Camera::new(150, 200, PI / 2.);
+        assert!((c.pixel_size() - 0.010).abs() < EPSILON);
+    }
+    #[test]
+    fn ray_for_pixel() {
+        // Constructing a ray through the center of the canvas.
+        let c = Camera::new(201, 101, PI / 2.);
+        let r = c.ray_for_pixel(100, 50);
+        assert_eq!(r.origin, point(0., 0., 0.));
+        assert_eq!(r.direction, vector(0., 0., -1.));
+
+        // Constructing a ray through the corner of the canvas.
+        let c = Camera::new(201, 101, PI / 2.);
+        let r = c.ray_for_pixel(0, 0);
+        assert_eq!(r.origin, point(0., 0., 0.));
+        assert_eq!(r.direction, vector(0.66519, 0.33259, -0.66851));
+
+        // Constructing a ray when the camera is transformed.
+        let mut c = Camera::new(201, 101, PI / 2.);
+        c.set_transform(Matrix4x4::rotation_y(PI / 4.) * Matrix4x4::translation(0., -2., 5.));
+        let r = c.ray_for_pixel(100, 50);
+        assert_eq!(r.origin, point(0., 2., -5.));
+        assert_eq!(
+            r.direction,
+            vector((2. as Float).sqrt() / 2., 0., -(2. as Float).sqrt() / 2.)
+        );
+    }
+    #[test]
+    fn render() {
+        // Rendering a world with a camera.
+        let w = World::test_world();
+        let mut c = Camera::new(11, 11, PI / 2.);
+        let from = point(0., 0., -5.);
+        let to = point(0., 0., 0.);
+        let up = vector(0., 1., 0.);
+        c.set_transform(view_transform(from, to, up));
+        let image = c.render(&w);
+        assert_eq!(image.get(5, 5), [0.38066, 0.47583, 0.2855].into());
+    }
+}

rtchallenge/src/canvas.rs

@@ -1,6 +1,4 @@
-use std::fs::File;
+use std::{fs::File, io::BufWriter, path::Path};
-use std::io::BufWriter;
-use std::path::Path;
 
 use png;
 use thiserror::Error;
@@ -48,7 +46,7 @@ impl Canvas {
     {
         let path = Path::new(path.as_ref());
         let file = File::create(path)?;
-        let ref mut w = BufWriter::new(file);
+        let w = &mut BufWriter::new(file);
 
         let mut encoder = png::Encoder::new(w, self.width as u32, self.height as u32);
         encoder.set_color(png::ColorType::RGB);

rtchallenge/src/intersections.rs

@@ -3,114 +3,50 @@ use std::ops::Index;
 use crate::{
     rays::Ray,
     shapes::Shape,
-    tuples::{dot, Tuple},
+    tuples::{dot, reflect, Tuple},
     Float, EPSILON,
 };
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone)]
 pub struct Intersection<'i> {
     pub t: Float,
     pub object: &'i Shape,
 }
+impl<'i> PartialEq for Intersection<'i> {
+    fn eq(&self, rhs: &Intersection) -> bool {
+        ((self.t - rhs.t).abs() < EPSILON) && (self.object == rhs.object)
+    }
+}
 
 impl<'i> Intersection<'i> {
     /// Create new `Intersection` at the given `t` that hits the given `object`.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{intersections::Intersection, shapes::Shape};
-    ///
-    /// // An intersection ecapsulates t and object.
-    /// let s = Shape::sphere();
-    /// let i = Intersection::new(3.5, &s);
-    /// assert_eq!(i.t, 3.5);
-    /// assert_eq!(i.object, &s);
-    /// ```
     pub fn new(t: Float, object: &Shape) -> Intersection {
         Intersection { t, object }
     }
 }
 
 /// Aggregates `Intersection`s.
-///
-/// # Examples
-/// ```
-/// use rtchallenge::{
-///     intersections::{Intersection, Intersections},
-///     rays::Ray,
-///     shapes::{intersect, Shape},
-///     tuples::Tuple,
-/// };
-///
-/// let s = Shape::sphere();
-/// let i1 = Intersection::new(1., &s);
-/// let i2 = Intersection::new(2., &s);
-/// let xs = Intersections::new(vec![i1, i2]);
-/// assert_eq!(xs.len(), 2);
-/// assert_eq!(xs[0].t, 1.);
-/// assert_eq!(xs[1].t, 2.);
-///
-/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-/// let xs = intersect(&s, &r);
-/// assert_eq!(xs.len(), 2);
-/// assert_eq!(xs[0].object, &s);
-/// assert_eq!(xs[1].object, &s);
-/// ```
 #[derive(Debug, Default, PartialEq)]
 pub struct Intersections<'i>(Vec<Intersection<'i>>);
 
+/// Create an [Intersections] from a single [Intersection] to aid in tests.
+impl<'i> From<Intersection<'i>> for Intersections<'i> {
+    fn from(i: Intersection<'i>) -> Intersections<'i> {
+        Intersections::new(vec![i])
+    }
+}
+
 impl<'i> Intersections<'i> {
     pub fn new(xs: Vec<Intersection<'i>>) -> Intersections {
         Intersections(xs)
     }
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
     pub fn len(&self) -> usize {
         self.0.len()
     }
     /// Finds nearest hit for this collection of intersections.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{
-    ///     intersections::{Intersection, Intersections},
-    ///     rays::Ray,
-    ///     shapes::{intersect, Shape},
-    ///     tuples::Tuple,
-    /// };
-    ///
-    /// // The hit, when all intersections have positive t.
-    /// let s = Shape::sphere();
-    /// let i1 = Intersection::new(1., &s);
-    /// let i2 = Intersection::new(2., &s);
-    /// let xs = Intersections::new(vec![i2, i1.clone()]);
-    /// let i = xs.hit();
-    /// assert_eq!(i, Some(&i1));
-    ///
-    /// // The hit, when some intersections have negative t.
-    /// let s = Shape::sphere();
-    /// let i1 = Intersection::new(-1., &s);
-    /// let i2 = Intersection::new(1., &s);
-    /// let xs = Intersections::new(vec![i2.clone(), i1]);
-    /// let i = xs.hit();
-    /// assert_eq!(i, Some(&i2));
-    ///
-    /// // The hit, when all intersections have negative t.
-    /// let s = Shape::sphere();
-    /// let i1 = Intersection::new(-2., &s);
-    /// let i2 = Intersection::new(-1., &s);
-    /// let xs = Intersections::new(vec![i2, i1]);
-    /// let i = xs.hit();
-    /// assert_eq!(i, None);
-    ///
-    /// // The hit is always the lowest nonnegative intersection.
-    /// let s = Shape::sphere();
-    /// let i1 = Intersection::new(5., &s);
-    /// let i2 = Intersection::new(7., &s);
-    /// let i3 = Intersection::new(-3., &s);
-    /// let i4 = Intersection::new(2., &s);
-    /// let xs = Intersections::new(vec![i1, i2, i3, i4.clone()]);
-    /// let i = xs.hit();
-    /// assert_eq!(i, Some(&i4));
-    /// ```
     pub fn hit(&self) -> Option<&Intersection> {
         self.0.iter().filter(|i| i.t > 0.).min_by(|i1, i2| {
             i1.t.partial_cmp(&i2.t)
@@ -140,81 +76,358 @@ pub struct PrecomputedData<'i> {
     pub t: Float,
     pub object: &'i Shape,
     pub point: Tuple,
+    pub under_point: Tuple,
     pub over_point: Tuple,
     pub eyev: Tuple,
     pub normalv: Tuple,
+    pub reflectv: Tuple,
     pub inside: bool,
+    pub n1: Float,
+    pub n2: Float,
 }
 
 /// Precomputes data common to all intersections.
-///
+pub fn prepare_computations<'i>(
-/// # Examples
+    hit: &'i Intersection,
-/// ```
+    r: &Ray,
-/// use rtchallenge::{
+    xs: &Intersections,
-///     intersections::{prepare_computations, Intersection, Intersections},
+) -> PrecomputedData<'i> {
-///     rays::Ray,
+    let point = r.position(hit.t);
-///     matrices::Matrix4x4,
+    let normalv = hit.object.normal_at(point);
-///     shapes::{intersect, Shape},
-///     tuples::Tuple,
-///     EPSILON
-/// };
-///
-/// // Precomputing the state of an intersection.
-/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-/// let shape = Shape::sphere();
-/// let i = Intersection::new(4., &shape);
-/// let comps = prepare_computations(&i, &r);
-/// assert_eq!(comps.t, i.t);
-/// assert_eq!(comps.object, i.object);
-/// assert_eq!(comps.point, Tuple::point(0., 0., -1.));
-/// assert_eq!(comps.eyev, Tuple::vector(0., 0., -1.));
-/// assert_eq!(comps.normalv, Tuple::vector(0., 0., -1.));
-///
-/// // The hit, when an intersection occurs on the outside.
-/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-/// let shape = Shape::sphere();
-/// let i = Intersection::new(4., &shape);
-/// let comps = prepare_computations(&i, &r);
-/// assert_eq!(comps.inside, false);
-///
-/// // The hit, when an intersection occurs on the inside.
-/// let r = Ray::new(Tuple::point(0., 0., 0.), Tuple::vector(0., 0., 1.));
-/// let shape = Shape::sphere();
-/// let i = Intersection::new(1., &shape);
-/// let comps = prepare_computations(&i, &r);
-/// assert_eq!(comps.point, Tuple::point(0., 0., 1.));
-/// assert_eq!(comps.eyev, Tuple::vector(0., 0., -1.));
-/// assert_eq!(comps.inside, true);
-//// // Normal would have been (0, 0, 1), but is inverted when inside.
-/// assert_eq!(comps.normalv, Tuple::vector(0., 0., -1.));
-///
-/// // The hit should offset the point.
-/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-/// let mut shape = Shape::sphere();
-/// shape .set_transform(Matrix4x4::translation(0.,0.,1.));
-/// let i = Intersection::new(5., &shape);
-/// let comps = prepare_computations(&i, &r);
-/// assert!(comps.over_point.z< -EPSILON/2.);
-/// assert!(comps.point.z>comps.over_point.z);
-/// ```
-pub fn prepare_computations<'i>(i: &'i Intersection, r: &Ray) -> PrecomputedData<'i> {
-    let point = r.position(i.t);
-    let normalv = i.object.normal_at(point);
     let eyev = -r.direction;
     let (inside, normalv) = if dot(normalv, eyev) < 0. {
         (true, -normalv)
     } else {
         (false, normalv)
     };
+    let reflectv = reflect(r.direction, normalv);
+
+    let mut n1 = -1.;
+    let mut n2 = -1.;
+    let mut containers: Vec<&Shape> = Vec::new();
+    for i in xs.0.iter() {
+        if hit == i {
+            if containers.is_empty() {
+                n1 = 1.;
+            } else {
+                n1 = containers.last().unwrap().material.refractive_index;
+            }
+        }
+
+        match containers.iter().position(|o| o == &i.object) {
+            Some(idx) => {
+                containers.remove(idx);
+            }
+            None => containers.push(i.object),
+        }
+
+        if hit == i {
+            if containers.is_empty() {
+                n2 = 1.;
+            } else {
+                n2 = containers.last().unwrap().material.refractive_index;
+            }
+            break;
+        }
+    }
 
     let over_point = point + normalv * EPSILON;
+    let under_point = point - normalv * EPSILON;
     PrecomputedData {
-        t: i.t,
+        t: hit.t,
-        object: i.object,
+        object: hit.object,
         point,
         over_point,
+        under_point,
         normalv,
+        reflectv,
         inside,
         eyev,
+        n1,
+        n2,
+    }
+}
+
+/// Compute Schlick approximation to Fresnel's equations.
+pub fn schlick(comps: &PrecomputedData) -> Float {
+    // Find the cosine of the angle between the eye and normal vectors.
+    let mut cos = dot(comps.eyev, comps.normalv);
+    // Total internal reflection can only occur if n1 > n2.
+    if comps.n1 > comps.n2 {
+        let n = comps.n1 / comps.n2;
+        let sin2_t = n * n * (1. - cos * cos);
+        if sin2_t > 1. {
+            return 1.;
+        }
+        // Compute cosine of theta_t using trig identity.
+        let cos_t = (1. - sin2_t).sqrt();
+        // When n1 > n2 use cos(theta_t) instead.
+        cos = cos_t;
+    }
+
+    let r0 = (comps.n1 - comps.n2) / (comps.n1 + comps.n2);
+    let r0 = r0 * r0;
+    r0 + (1. - r0) * (1. - cos) * (1. - cos) * (1. - cos) * (1. - cos) * (1. - cos)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        intersections::{prepare_computations, schlick, Intersection, Intersections},
+        materials::MaterialBuilder,
+        matrices::{scaling, translation},
+        rays::Ray,
+        shapes::{glass_sphere, intersect, Shape},
+        tuples::{point, vector},
+        Float, EPSILON,
+    };
+
+    #[test]
+    fn intersection() {
+        // An intersection ecapsulates t and object.
+        let s = Shape::sphere();
+        let i = Intersection::new(3.5, &s);
+        assert_eq!(i.t, 3.5);
+        assert_eq!(i.object, &s);
+    }
+    #[test]
+    fn intersections() {
+        let s = Shape::sphere();
+        let i1 = Intersection::new(1., &s);
+        let i2 = Intersection::new(2., &s);
+        let xs = Intersections::new(vec![i1, i2]);
+        assert_eq!(xs.len(), 2);
+        assert_eq!(xs[0].t, 1.);
+        assert_eq!(xs[1].t, 2.);
+
+        let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+        let xs = intersect(&s, &r);
+        assert_eq!(xs.len(), 2);
+        assert_eq!(xs[0].object, &s);
+        assert_eq!(xs[1].object, &s);
+    }
+
+    mod hit {
+        use super::*;
+
+        #[test]
+        fn when_all_intersections_have_positive_t() {
+            let s = Shape::sphere();
+            let i1 = Intersection::new(1., &s);
+            let i2 = Intersection::new(2., &s);
+            let xs = Intersections::new(vec![i2, i1.clone()]);
+            let i = xs.hit();
+            assert_eq!(i, Some(&i1));
+        }
+        #[test]
+        fn when_some_intersections_have_negative_t() {
+            let s = Shape::sphere();
+            let i1 = Intersection::new(-1., &s);
+            let i2 = Intersection::new(1., &s);
+            let xs = Intersections::new(vec![i2.clone(), i1]);
+            let i = xs.hit();
+            assert_eq!(i, Some(&i2));
+        }
+        #[test]
+        fn when_all_intersections_have_negative_t() {
+            let s = Shape::sphere();
+            let i1 = Intersection::new(-2., &s);
+            let i2 = Intersection::new(-1., &s);
+            let xs = Intersections::new(vec![i2, i1]);
+            let i = xs.hit();
+            assert_eq!(i, None);
+        }
+        #[test]
+        fn always_the_lowest_nonnegative_intersection() {
+            let s = Shape::sphere();
+            let i1 = Intersection::new(5., &s);
+            let i2 = Intersection::new(7., &s);
+            let i3 = Intersection::new(-3., &s);
+            let i4 = Intersection::new(2., &s);
+            let xs = Intersections::new(vec![i1, i2, i3, i4.clone()]);
+            let i = xs.hit();
+            assert_eq!(i, Some(&i4));
+        }
+    }
+
+    mod prepare_computations {
+        use super::*;
+
+        #[test]
+        fn precomputing_the_state_of_intersection() -> Result<(), Box<dyn std::error::Error>> {
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let shape = Shape::sphere();
+            let xs = Intersections::from(Intersection::new(4., &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert_eq!(comps.t, xs[0].t);
+            assert_eq!(comps.object, xs[0].object);
+            assert_eq!(comps.point, point(0., 0., -1.));
+            assert_eq!(comps.eyev, vector(0., 0., -1.));
+            assert_eq!(comps.normalv, vector(0., 0., -1.));
+            Ok(())
+        }
+
+        #[test]
+        fn hit_when_intersection_occurs_outside() -> Result<(), Box<dyn std::error::Error>> {
+            // The hit, when an intersection occurs on the outside.
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let shape = Shape::sphere();
+            let xs = Intersections::from(Intersection::new(4., &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert_eq!(comps.inside, false);
+            Ok(())
+        }
+
+        #[test]
+        fn hit_when_intersection_occurs_inside() -> Result<(), Box<dyn std::error::Error>> {
+            // The hit, when an intersection occurs on the inside.
+            let r = Ray::new(point(0., 0., 0.), vector(0., 0., 1.));
+            let shape = Shape::sphere();
+            let xs = Intersections::from(Intersection::new(1., &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert_eq!(comps.point, point(0., 0., 1.));
+            assert_eq!(comps.eyev, vector(0., 0., -1.));
+            assert_eq!(comps.inside, true);
+            // Normal would have been (0, 0, 1), but is inverted when inside.
+            assert_eq!(comps.normalv, vector(0., 0., -1.));
+            Ok(())
+        }
+
+        #[test]
+        fn hit_should_offset_the_point() -> Result<(), Box<dyn std::error::Error>> {
+            // The hit should offset the point.
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let mut shape = Shape::sphere();
+            shape.set_transform(translation(0., 0., 1.));
+            let xs = Intersections::from(Intersection::new(5., &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert!(comps.over_point.z < -EPSILON / 2.);
+            assert!(comps.point.z > comps.over_point.z);
+            Ok(())
+        }
+
+        #[test]
+        fn precomputing_the_reflection_vector() -> Result<(), Box<dyn std::error::Error>> {
+            // Precomputing the reflection vector.
+            let shape = Shape::plane();
+            let r = Ray::new(
+                point(0., 1., -1.),
+                vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
+            );
+            let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert_eq!(
+                comps.reflectv,
+                vector(0., (2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.)
+            );
+            Ok(())
+        }
+
+        #[test]
+        fn finding_n1_and_n2() -> Result<(), Box<dyn std::error::Error>> {
+            // Finding n1 and n2 at various intersections.
+            let a = glass_sphere()
+                .transform(scaling(2., 2., 2.))
+                .material(
+                    MaterialBuilder::default()
+                        .transparency(1.)
+                        .refractive_index(1.5)
+                        .build()?,
+                )
+                .build()?;
+            let b = glass_sphere()
+                .transform(translation(0., 0., -0.25))
+                .material(
+                    MaterialBuilder::default()
+                        .transparency(1.)
+                        .refractive_index(2.)
+                        .build()?,
+                )
+                .build()?;
+            let c = glass_sphere()
+                .transform(translation(0., 0., 0.25))
+                .material(
+                    MaterialBuilder::default()
+                        .transparency(1.)
+                        .refractive_index(2.5)
+                        .build()?,
+                )
+                .build()?;
+            let r = Ray::new(point(0., 0., -4.), vector(0., 0., 1.));
+            let xs = Intersections::new(vec![
+                Intersection::new(2., &a),
+                Intersection::new(2.75, &b),
+                Intersection::new(3.25, &c),
+                Intersection::new(4.75, &b),
+                Intersection::new(5.25, &c),
+                Intersection::new(6., &a),
+            ]);
+            for (index, n1, n2) in &[
+                (0, 1.0, 1.5),
+                (1, 1.5, 2.0),
+                (2, 2.0, 2.5),
+                (3, 2.5, 2.5),
+                (4, 2.5, 1.5),
+                (5, 1.5, 1.0),
+            ] {
+                let comps = prepare_computations(&xs[*index], &r, &xs);
+                assert_eq!(comps.n1, *n1);
+                assert_eq!(comps.n2, *n2);
+            }
+            Ok(())
+        }
+
+        #[test]
+        fn under_point_offset_below_surface() -> Result<(), Box<dyn std::error::Error>> {
+            // The under point is offset below the surface.
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let shape = glass_sphere().transform(translation(0., 0., 1.)).build()?;
+            let xs = Intersections::from(Intersection::new(5., &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            assert!(comps.under_point.z > EPSILON / 2.);
+            assert!(comps.point.z < comps.under_point.z);
+
+            Ok(())
+        }
+    }
+    mod schlick {
+        use super::*;
+
+        #[test]
+        fn under_total_reflection() -> Result<(), Box<dyn std::error::Error>> {
+            let shape = glass_sphere().build()?;
+            let r = Ray::new(point(0., 0., (2 as Float).sqrt() / 2.), vector(0., 1., 0.));
+            let xs = Intersections::new(vec![
+                Intersection::new(-(2 as Float).sqrt() / 2., &shape),
+                Intersection::new((2 as Float).sqrt() / 2., &shape),
+            ]);
+            let comps = prepare_computations(&xs[1], &r, &xs);
+            let reflectance = schlick(&comps);
+            assert_eq!(reflectance, 1.);
+            Ok(())
+        }
+        #[test]
+        fn perpendicular_viewing_angle() -> Result<(), Box<dyn std::error::Error>> {
+            let shape = glass_sphere().build()?;
+            let r = Ray::new(point(0., 0., 0.), vector(0., 1., 0.));
+            let xs = Intersections::new(vec![
+                Intersection::new(-1., &shape),
+                Intersection::new(1., &shape),
+            ]);
+            let comps = prepare_computations(&xs[1], &r, &xs);
+            let reflectance = schlick(&comps);
+            assert!((reflectance - 0.04).abs() < EPSILON);
+            Ok(())
+        }
+        #[test]
+        fn small_angle_n2_greater_n1() -> Result<(), Box<dyn std::error::Error>> {
+            let shape = glass_sphere().build()?;
+            let r = Ray::new(point(0., 0.99, -2.), vector(0., 0., 1.));
+            let xs = Intersections::new(vec![Intersection::new(1.8589, &shape)]);
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let reflectance = schlick(&comps);
+            assert!((reflectance - 0.48873).abs() < EPSILON);
+            Ok(())
+        }
     }
 }

rtchallenge/src/lib.rs

@@ -4,6 +4,7 @@ pub mod intersections;
 pub mod lights;
 pub mod materials;
 pub mod matrices;
+pub mod patterns;
 pub mod rays;
 pub mod shapes;
 pub mod transformations;
@@ -37,3 +38,18 @@ pub mod float {
 }
 
 pub use float::Float;
+
+pub mod prelude {
+    pub use crate::{
+        camera::{Camera, CameraBuilder},
+        lights::{PointLight, PointLightBuilder},
+        materials::{Material, MaterialBuilder},
+        matrices::{identity, rotation_x, rotation_y, rotation_z, scaling, shearing, translation},
+        patterns::{checkers_pattern, gradient_pattern, ring_pattern, stripe_pattern},
+        shapes::{cube, plane, sphere, test_shape},
+        transformations::view_transform,
+        tuples::{point, vector, Color},
+        world::{World, WorldBuilder},
+        Float,
+    };
+}

rtchallenge/src/lights.rs

@@ -1,33 +1,39 @@
+use derive_builder::Builder;
+
 use crate::tuples::{Color, Tuple};
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Builder, Clone, Debug, Default, PartialEq)]
+#[builder(default)]
 pub struct PointLight {
     pub position: Tuple,
+    #[builder(setter(into))]
     pub intensity: Color,
 }
 
 impl PointLight {
     /// Creates a new `PositionLight` at the given `position` and with the given
     /// `intensity`.
-    ///
+    pub fn new<C>(position: Tuple, intensity: C) -> PointLight
-    /// # Examples
+    where
-    /// ```
+        C: Into<Color>,
-    /// use rtchallenge::{
+    {
-    ///     lights::PointLight,
-    ///     tuples::{Color, Tuple},
-    ///     WHITE,
-    /// };
-    ///
-    /// let intensity = WHITE;
-    /// let position = Tuple::point(0., 0., 0.);
-    /// let light = PointLight::new(position, intensity);
-    /// assert_eq!(light.position, position);
-    /// assert_eq!(light.intensity, intensity);
-    /// ```
-    pub fn new(position: Tuple, intensity: Color) -> PointLight {
         PointLight {
             position,
-            intensity,
+            intensity: intensity.into(),
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{lights::PointLight, tuples::point, WHITE};
+
+    #[test]
+    fn new() {
+        let intensity = WHITE;
+        let position = point(0., 0., 0.);
+        let light = PointLight::new(position, intensity);
+        assert_eq!(light.position, position);
+        assert_eq!(light.intensity, intensity);
+    }
+}

rtchallenge/src/materials.rs

@@ -1,108 +1,47 @@
+use derive_builder::Builder;
+
 use crate::{
     lights::PointLight,
-    tuples::Color,
+    patterns::Pattern,
-    tuples::{dot, reflect, Tuple},
+    shapes::Shape,
+    tuples::{dot, reflect, Color, Tuple},
     Float, BLACK, WHITE,
 };
-#[derive(Debug, PartialEq, Clone)]
+
+#[derive(Builder, Debug, PartialEq, Clone)]
+#[builder(default)]
 pub struct Material {
-    pub color: Color,
+    #[builder(setter(into))]
+    pub color: Pattern,
     pub ambient: Float,
     pub diffuse: Float,
     pub specular: Float,
     pub shininess: Float,
+    pub reflective: Float,
+    pub transparency: Float,
+    pub refractive_index: Float,
 }
 
 impl Default for Material {
     /// Creates the default material.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{materials::Material, tuples::Color, WHITE};
-    ///
-    /// let m = Material::default();
-    /// assert_eq!(
-    ///     m,
-    ///     Material {
-    ///         color: WHITE,
-    ///         ambient: 0.1,
-    ///         diffuse: 0.9,
-    ///         specular: 0.9,
-    ///         shininess: 200.,
-    ///     }
-    /// );
-    /// ```
     fn default() -> Material {
         Material {
-            color: WHITE,
+            color: WHITE.into(),
             ambient: 0.1,
             diffuse: 0.9,
             specular: 0.9,
             shininess: 200.,
+            reflective: 0.0,
+            transparency: 0.0,
+            refractive_index: 1.0,
         }
     }
 }
 
 /// Compute lighting contributions using the Phong reflection model.
-///
-/// # Examples
-/// ```
-/// use rtchallenge::{
-///     lights::PointLight,
-///     materials::{lighting, Material},
-///     tuples::{Color, Tuple},
-///     Float, WHITE,
-/// };
-///
-/// let in_shadow = false;
-/// let m = Material::default();
-/// let position = Tuple::point(0., 0., 0.);
-///
-/// // Lighting with the eye between the light and the surface.
-/// let eyev = Tuple::vector(0., 0., -1.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 0., -10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, Color::new(1.9, 1.9, 1.9));
-///
-/// // Lighting with the eye between the light and the surface, eye offset 45°.
-/// let eyev = Tuple::vector(0., (2. as Float).sqrt() / 2., -(2. as Float).sqrt() / 2.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 0., -10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, WHITE);
-///
-/// // Lighting with the eye opposite surface, light offset 45°.
-/// let eyev = Tuple::vector(0., 0., -1.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 10., -10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, Color::new(0.7364, 0.7364, 0.7364));
-///
-/// // Lighting with the eye in the path of the reflection vector.
-/// let eyev = Tuple::vector(0., -(2.0 as Float).sqrt() / 2., -(2.0 as Float).sqrt() / 2.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 10., -10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, Color::new(1.63639, 1.63639, 1.63639));
-///
-/// // Lighting with the light behind the surface.
-/// let eyev = Tuple::vector(0., 0., -1.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 0., 10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, Color::new(0.1, 0.1, 0.1));
-///
-/// // Lighting with the surface in shadow.
-/// let in_shadow = true;
-/// let eyev = Tuple::vector(0., 0., -1.);
-/// let normalv = Tuple::vector(0., 0., -1.);
-/// let light = PointLight::new(Tuple::point(0., 0., -10.), WHITE);
-/// let result = lighting(&m, &light, position, eyev, normalv, in_shadow);
-/// assert_eq!(result, Color::new(0.1, 0.1, 0.1));
-/// ```
 pub fn lighting(
     material: &Material,
+    object: &Shape,
     light: &PointLight,
     point: Tuple,
     eyev: Tuple,
@@ -110,7 +49,8 @@ pub fn lighting(
     in_shadow: bool,
 ) -> Color {
     // Combine the surface color with the light's color.
-    let effective_color = material.color * light.intensity;
+    let color = material.color.pattern_at_object(object, point);
+    let effective_color = color * light.intensity;
     // Find the direciton of the light source.
     let lightv = (light.position - point).normalize();
     // Compute the ambient distribution.
@@ -144,3 +84,153 @@ pub fn lighting(
         ambient + diffuse + specular
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{materials::Material, WHITE};
+
+    #[test]
+    fn default() {
+        let m = Material::default();
+        assert_eq!(
+            m,
+            Material {
+                color: WHITE.into(),
+                ambient: 0.1,
+                diffuse: 0.9,
+                specular: 0.9,
+                shininess: 200.,
+                reflective: 0.0,
+                transparency: 0.0,
+                refractive_index: 1.0,
+            }
+        );
+    }
+
+    mod lighting {
+        use crate::{
+            lights::PointLight,
+            materials::{lighting, Material},
+            patterns::{Pattern, BLACK_PAT, WHITE_PAT},
+            shapes::Shape,
+            tuples::{point, vector, Color},
+            Float, BLACK, WHITE,
+        };
+
+        #[test]
+        fn eye_between_light_and_surface() {
+            let in_shadow = false;
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+
+            // Lighting with the eye between the light and the surface.
+            let eyev = vector(0., 0., -1.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 0., -10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, Color::new(1.9, 1.9, 1.9));
+        }
+
+        #[test]
+        fn eye_between_light_and_surface_offset_45() {
+            // Lighting with the eye between the light and the surface, eye offset 45°.
+            let in_shadow = false;
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+            let eyev = vector(0., (2. as Float).sqrt() / 2., -(2. as Float).sqrt() / 2.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 0., -10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, WHITE);
+        }
+        #[test]
+        fn eye_opposite_surface_light_offset_45() {
+            // Lighting with the eye opposite surface, light offset 45°.
+            let in_shadow = false;
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+            let eyev = vector(0., 0., -1.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 10., -10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, Color::new(0.7364, 0.7364, 0.7364));
+        }
+        #[test]
+        fn eye_in_path_of_reflection_vector() {
+            // Lighting with the eye in the path of the reflection vector.
+            let in_shadow = false;
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+            let eyev = vector(0., -(2.0 as Float).sqrt() / 2., -(2.0 as Float).sqrt() / 2.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 10., -10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, Color::new(1.63639, 1.63639, 1.63639));
+        }
+        #[test]
+        fn light_behind_surface() {
+            // Lighting with the light behind the surface.
+            let in_shadow = false;
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+            let eyev = vector(0., 0., -1.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 0., 10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, Color::new(0.1, 0.1, 0.1));
+        }
+        #[test]
+        fn surface_in_shadow() {
+            // Lighting with the surface in shadow.
+            let m = Material::default();
+            let position = point(0., 0., 0.);
+            let object = Shape::sphere();
+            let in_shadow = true;
+            let eyev = vector(0., 0., -1.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 0., -10.), WHITE);
+            let result = lighting(&m, &object, &light, position, eyev, normalv, in_shadow);
+            assert_eq!(result, Color::new(0.1, 0.1, 0.1));
+        }
+        #[test]
+        fn pattern_applied() {
+            // Lighting with a pattern applied.
+            let object = Shape::sphere();
+            let m = Material {
+                color: Pattern::stripe(WHITE_PAT, BLACK_PAT),
+                ambient: 1.,
+                diffuse: 0.,
+                specular: 0.,
+                ..Material::default()
+            };
+            let eyev = vector(0., 0., -1.);
+            let normalv = vector(0., 0., -1.);
+            let light = PointLight::new(point(0., 0., -10.), WHITE);
+            let c1 = lighting(
+                &m,
+                &object,
+                &light,
+                point(0.9, 0., 0.),
+                eyev,
+                normalv,
+                false,
+            );
+            let c2 = lighting(
+                &m,
+                &object,
+                &light,
+                point(1.1, 0., 0.),
+                eyev,
+                normalv,
+                false,
+            );
+            assert_eq!(c1, WHITE);
+            assert_eq!(c2, BLACK);
+        }
+    }
+}

rtchallenge/src/matrices.rs

@@ -1,8 +1,39 @@
-use std::fmt;
+use std::{
-use std::ops::{Index, IndexMut, Mul, Sub};
+    fmt,
+    ops::{Index, IndexMut, Mul, Sub},
+};
 
 use crate::{tuples::Tuple, Float, EPSILON};
 
+/// Short hand for creating a Matrix4x4 set to the identity matrix.
+pub fn identity() -> Matrix4x4 {
+    Matrix4x4::identity()
+}
+/// Short hand for creating a Matrix4x4 for rotating around the X-axis.
+pub fn rotation_x(radians: Float) -> Matrix4x4 {
+    Matrix4x4::rotation_x(radians)
+}
+/// Short hand for creating a Matrix4x4 for rotating around the Y-axis.
+pub fn rotation_y(radians: Float) -> Matrix4x4 {
+    Matrix4x4::rotation_y(radians)
+}
+/// Short hand for creating a Matrix4x4 for rotating around the Z-axis.
+pub fn rotation_z(radians: Float) -> Matrix4x4 {
+    Matrix4x4::rotation_z(radians)
+}
+/// Short hand for creating a Matrix4x4 that scales in the given x,y,z axis.
+pub fn scaling(x: Float, y: Float, z: Float) -> Matrix4x4 {
+    Matrix4x4::scaling(x, y, z)
+}
+/// Short hand for creating a Matrix4x4 that shears across the given axis pairs.
+pub fn shearing(xy: Float, xz: Float, yx: Float, yz: Float, zx: Float, zy: Float) -> Matrix4x4 {
+    Matrix4x4::shearing(xy, xz, yx, yz, zx, zy)
+}
+/// Short hand for creating a Matrix4x4 that translations along the given x,y,z axis.
+pub fn translation(x: Float, y: Float, z: Float) -> Matrix4x4 {
+    Matrix4x4::translation(x, y, z)
+}
+
 #[derive(Debug)]
 pub struct Matrix2x2 {
     m: [[Float; 2]; 2],
@@ -14,16 +45,6 @@ impl Matrix2x2 {
     }
 
     /// Calculate the determinant of a 2x2.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::matrices::Matrix2x2;
-    ///
-    /// let a = Matrix2x2::new([1., 5.], [-3., 2.]);
-    ///
-    /// assert_eq!(a.determinant(), 17.);
-    /// ```
     pub fn determinant(&self) -> Float {
         let m = self;
         m[(0, 0)] * m[(1, 1)] - m[(0, 1)] * m[(1, 0)]
@@ -61,16 +82,6 @@ impl Matrix3x3 {
         Matrix3x3 { m: [r0, r1, r2] }
     }
     /// submatrix extracts a 2x2 matrix ignoring the 0-based `row` and `col` given.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::{Matrix2x2, Matrix3x3};
-    ///
-    /// assert_eq!(
-    ///     Matrix3x3::new([1., 5., 0.], [-3., 2., 7.], [0., 6., -3.],).submatrix(0, 2),
-    ///     Matrix2x2::new([-3., 2.], [0., 6.])
-    /// );
-    /// ```
     pub fn submatrix(&self, row: usize, col: usize) -> Matrix2x2 {
         assert!(row < 3);
         assert!(col < 3);
@@ -91,49 +102,17 @@ impl Matrix3x3 {
     }
 
     /// Compute minor of a 3x3 matrix.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix3x3;
-    ///
-    /// let a = Matrix3x3::new([3., 5., 0.], [2., -1., -7.], [6., -1., 5.]);
-    /// let b = a.submatrix(1, 0);
-    /// assert_eq!(b.determinant(), 25.0);
-    /// assert_eq!(b.determinant(), a.minor(1, 0));
-    /// ```
     pub fn minor(&self, row: usize, col: usize) -> Float {
         self.submatrix(row, col).determinant()
     }
 
     /// Compute cofactor of a 3x3 matrix.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix3x3;
-    ///
-    /// let a = Matrix3x3::new([3., 5., 0.], [2., -1., -7.], [6., -1., 5.]);
-    /// assert_eq!(a.minor(0, 0), -12.);
-    /// assert_eq!(a.cofactor(0, 0), -12.);
-    /// assert_eq!(a.minor(1, 0), 25.);
-    /// assert_eq!(a.cofactor(1, 0), -25.);
-    /// ```
     pub fn cofactor(&self, row: usize, col: usize) -> Float {
         let negate = if (row + col) % 2 == 0 { 1. } else { -1. };
         self.submatrix(row, col).determinant() * negate
     }
 
     /// Compute determinant of a 3x3 matrix.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix3x3;
-    ///
-    /// let a = Matrix3x3::new([1., 2., 6.], [-5., 8., -4.], [2., 6., 4.]);
-    /// assert_eq!(a.cofactor(0, 0), 56.);
-    /// assert_eq!(a.cofactor(0, 1), 12.);
-    /// assert_eq!(a.cofactor(0, 2), -46.);
-    /// assert_eq!(a.determinant(), -196.);
-    /// ```
     pub fn determinant(&self) -> Float {
         (0..3).map(|i| self.cofactor(0, i) * self[(0, i)]).sum()
     }
@@ -163,34 +142,6 @@ impl PartialEq for Matrix3x3 {
 
 /// Matrix4x4 represents a 4x4 matrix in row-major form. So, element `m[i][j]` corresponds to m<sub>i,j</sub>
 /// where `i` is the row number and `j` is the column number.
-///
-/// # Examples
-/// ```
-/// use rtchallenge::{float::consts::PI, matrices::Matrix4x4, tuples::Tuple};
-///
-/// // Individual transformations are applied in sequence.
-/// let p = Tuple::point(1., 0., 1.);
-/// let a = Matrix4x4::rotation_x(PI / 2.);
-/// let b = Matrix4x4::scaling(5., 5., 5.);
-/// let c = Matrix4x4::translation(10., 5., 7.);
-/// // Apply rotation first.
-/// let p2 = a * p;
-/// assert_eq!(p2, Tuple::point(1., -1., 0.));
-/// // Then apply scaling.
-/// let p3 = b * p2;
-/// assert_eq!(p3, Tuple::point(5., -5., 0.));
-/// // Then apply translation.
-/// let p4 = c * p3;
-/// assert_eq!(p4, Tuple::point(15., 0., 7.));
-///
-/// // Chained transformations must be applied in reverse order.
-/// let p = Tuple::point(1., 0., 1.);
-/// let a = Matrix4x4::rotation_x(PI / 2.);
-/// let b = Matrix4x4::scaling(5., 5., 5.);
-/// let c = Matrix4x4::translation(10., 5., 7.);
-/// let t = c * b * a;
-/// assert_eq!(t * p, Tuple::point(15., 0., 7.));
-/// ```
 #[derive(Copy, Clone, Default)]
 pub struct Matrix4x4 {
     m: [[Float; 4]; 4],
@@ -211,22 +162,7 @@ impl From<[Float; 16]> for Matrix4x4 {
 
 impl Matrix4x4 {
     /// Create a `Matrix4x4` containing the identity, all zeros with ones along the diagonal.
-    /// # Examples
+    pub const fn identity() -> Matrix4x4 {
-    ///
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [0., 1., 2., 3.],
-    ///     [1., 2., 4., 8.],
-    ///     [2., 4., 8., 16.],
-    ///     [4., 8., 16., 32.],
-    /// );
-    /// let i = Matrix4x4::identity();
-    ///
-    /// assert_eq!(a * i, a);
-    /// ```
-    pub fn identity() -> Matrix4x4 {
         Matrix4x4::new(
             [1., 0., 0., 0.],
             [0., 1., 0., 0.],
@@ -236,29 +172,13 @@ impl Matrix4x4 {
     }
 
     /// Create a `Matrix4x4` with each of the given rows.
-    pub fn new(r0: [Float; 4], r1: [Float; 4], r2: [Float; 4], r3: [Float; 4]) -> Matrix4x4 {
+    pub const fn new(r0: [Float; 4], r1: [Float; 4], r2: [Float; 4], r3: [Float; 4]) -> Matrix4x4 {
         Matrix4x4 {
             m: [r0, r1, r2, r3],
         }
     }
 
     /// Creates a 4x4 matrix representing a translation of x,y,z.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{matrices::Matrix4x4, tuples::Tuple};
-    ///
-    /// let transform = Matrix4x4::translation(5., -3., 2.);
-    /// let p = Tuple::point(-3., 4., 5.);
-    /// assert_eq!(transform * p, Tuple::point(2., 1., 7.));
-    ///
-    /// let inv = transform.inverse();
-    /// assert_eq!(inv * p, Tuple::point(-8., 7., 3.));
-    ///
-    /// let v = Tuple::vector(-3., 4., 5.);
-    /// assert_eq!(transform * v, v);
-    /// ```
     pub fn translation(x: Float, y: Float, z: Float) -> Matrix4x4 {
         Matrix4x4::new(
             [1., 0., 0., x],
@@ -269,30 +189,6 @@ impl Matrix4x4 {
     }
 
     /// Creates a 4x4 matrix representing a scaling of x,y,z.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{matrices::Matrix4x4, tuples::Tuple};
-    ///
-    /// // A scaling matrix applied to a point.
-    /// let transform = Matrix4x4::scaling(2., 3., 4.);
-    /// let p = Tuple::point(-4., 6., 8.);
-    /// assert_eq!(transform * p, Tuple::point(-8., 18., 32.));
-    ///
-    /// // A scaling matrix applied to a vector.
-    /// let v = Tuple::vector(-4., 6., 8.);
-    /// assert_eq!(transform * v, Tuple::vector(-8., 18., 32.));
-    ///
-    /// // Multiplying by the inverse of a scaling matrix.
-    /// let inv = transform.inverse();
-    /// assert_eq!(inv * v, Tuple::vector(-2., 2., 2.));
-    ///
-    /// // Reflection is scaling by a negative value.
-    /// let transform = Matrix4x4::scaling(-1., 1., 1.);
-    /// let p = Tuple::point(2., 3., 4.);
-    /// assert_eq!(transform * p, Tuple::point(-2., 3., 4.));
-    /// ```
     pub fn scaling(x: Float, y: Float, z: Float) -> Matrix4x4 {
         Matrix4x4::new(
             [x, 0., 0., 0.],
@@ -303,23 +199,6 @@ impl Matrix4x4 {
     }
 
     /// Creates a 4x4 matrix representing a rotation around the x-axis.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{float::consts::PI, matrices::Matrix4x4, tuples::Tuple, Float};
-    ///
-    /// // A scaling matrix applied to a point.
-    /// let p = Tuple::point(0., 1., 0.);
-    /// let half_quarter = Matrix4x4::rotation_x(PI / 4.);
-    /// let full_quarter = Matrix4x4::rotation_x(PI / 2.);
-    ///
-    /// assert_eq!(
-    ///     half_quarter * p,
-    ///     Tuple::point(0., (2.0 as Float).sqrt() / 2., (2.0 as Float).sqrt() / 2.)
-    /// );
-    /// assert_eq!(full_quarter * p, Tuple::point(0., 0., 1.),);
-    /// ```
     pub fn rotation_x(radians: Float) -> Matrix4x4 {
         let r = radians;
         Matrix4x4::new(
@@ -331,23 +210,6 @@ impl Matrix4x4 {
     }
 
     /// Creates a 4x4 matrix representing a rotation around the y-axis.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{float::consts::PI, matrices::Matrix4x4, tuples::Tuple, Float};
-    ///
-    /// // A scaling matrix applied to a point.
-    /// let p = Tuple::point(0., 0., 1.);
-    /// let half_quarter = Matrix4x4::rotation_y(PI / 4.);
-    /// let full_quarter = Matrix4x4::rotation_y(PI / 2.);
-    ///
-    /// assert_eq!(
-    ///     half_quarter * p,
-    ///     Tuple::point((2.0 as Float).sqrt() / 2., 0., (2.0 as Float).sqrt() / 2.)
-    /// );
-    /// assert_eq!(full_quarter * p, Tuple::point(1., 0., 0.,),);
-    /// ```
     pub fn rotation_y(radians: Float) -> Matrix4x4 {
         let r = radians;
         Matrix4x4::new(
@@ -359,23 +221,6 @@ impl Matrix4x4 {
     }
 
     /// Creates a 4x4 matrix representing a rotation around the z-axis.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{float::consts::PI, matrices::Matrix4x4, tuples::Tuple, Float};
-    ///
-    /// // A scaling matrix applied to a point.
-    /// let p = Tuple::point(0., 1., 0.);
-    /// let half_quarter = Matrix4x4::rotation_z(PI / 4.);
-    /// let full_quarter = Matrix4x4::rotation_z(PI / 2.);
-    ///
-    /// assert_eq!(
-    ///     half_quarter * p,
-    ///     Tuple::point(-(2.0 as Float).sqrt() / 2., (2.0 as Float).sqrt() / 2., 0.)
-    /// );
-    /// assert_eq!(full_quarter * p, Tuple::point(-1., 0., 0.,),);
-    /// ```
     pub fn rotation_z(radians: Float) -> Matrix4x4 {
         let r = radians;
         Matrix4x4::new(
@@ -387,26 +232,6 @@ impl Matrix4x4 {
     }
 
     /// Transpose self, returning a new matrix that has been reflected across the diagonal.
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let m = Matrix4x4::new(
-    ///     [2., 0., 0., 0.],
-    ///     [3., 1., 0., 0.],
-    ///     [4., 0., 1., 0.],
-    ///     [5., 6., 7., 1.],
-    /// );
-    /// let m_t = Matrix4x4::new(
-    ///     [2., 3., 4., 5.],
-    ///     [0., 1., 0., 6.],
-    ///     [0., 0., 1., 7.],
-    ///     [0., 0., 0., 1.],
-    /// );
-    /// assert_eq!(m.transpose(), m_t);
-    ///
-    /// assert_eq!(Matrix4x4::identity(), Matrix4x4::identity().transpose());
     pub fn transpose(&self) -> Matrix4x4 {
         let m = self.m;
         Matrix4x4 {
@@ -420,40 +245,6 @@ impl Matrix4x4 {
     }
     /// Create a transform matrix that will shear (skew) points.
     /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::{matrices::Matrix4x4, tuples::Tuple};
-    ///
-    /// // A shearing transform moves x in proportion to y.
-    /// let transform = Matrix4x4::shearing(1.,0.,0.,0.,0.,0.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(5.,3.,4.));
-    ///
-    /// // A shearing transform moves x in proportion to z.
-    /// let transform = Matrix4x4::shearing(0.,1.,0.,0.,0.,0.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(6.,3.,4.));
-    ///
-    /// // A shearing transform moves y in proportion to x.
-    /// let transform = Matrix4x4::shearing(0.,0.,1.,0.,0.,0.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(2.,5.,4.));
-    ///
-    /// // A shearing transform moves y in proportion to z.
-    /// let transform = Matrix4x4::shearing(0.,0.,0.,1.,0.,0.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(2.,7.,4.));
-    ///
-    /// // A shearing transform moves z in proportion to x.
-    /// let transform = Matrix4x4::shearing(0.,0.,0.,0.,1.,0.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(2.,3.,6.));
-    ///
-    /// // A shearing transform moves z in proportion to y.
-    /// let transform = Matrix4x4::shearing(0.,0.,0.,0.,0.,1.);
-    /// let p = Tuple::point(2.,3.,4.);
-    /// assert_eq!(transform * p, Tuple::point(2.,3.,7.));
-
     pub fn shearing(xy: Float, xz: Float, yx: Float, yz: Float, zx: Float, zy: Float) -> Matrix4x4 {
         Matrix4x4::new(
             [1., xy, xz, 0.],
@@ -466,24 +257,6 @@ impl Matrix4x4 {
     /// Returns a new matrix that is the inverse of self. If self is A, inverse returns A<sup>-1</sup>, where
     /// AA<sup>-1</sup> = I.
     /// This implementation uses a numerically stable Gauss–Jordan elimination routine to compute the inverse.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let i = Matrix4x4::identity();
-    /// assert_eq!(i.inverse_rtiow() * i, i);
-    ///
-    /// let m = Matrix4x4::new(
-    ///     [2., 0., 0., 0.],
-    ///     [0., 3., 0., 0.],
-    ///     [0., 0., 4., 0.],
-    ///     [0., 0., 0., 1.],
-    /// );
-    /// assert_eq!(m.inverse_rtiow() * m, i);
-    /// assert_eq!(m * m.inverse_rtiow(), i);
-    /// ```
     pub fn inverse_rtiow(&self) -> Matrix4x4 {
         // TODO(wathiede): how come the C++ version doesn't need to deal with non-invertable
         // matrix.
@@ -558,22 +331,6 @@ impl Matrix4x4 {
         Matrix4x4 { m: minv }
     }
     /// submatrix extracts a 3x3 matrix ignoring the 0-based `row` and `col` given.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::{Matrix3x3, Matrix4x4};
-    ///
-    /// assert_eq!(
-    ///     Matrix4x4::new(
-    ///         [-6., 1., 1., 6.],
-    ///         [-8., 5., 8., 6.],
-    ///         [-1., 0., 8., 2.],
-    ///         [-7., 1., -1., 1.],
-    ///     )
-    ///     .submatrix(2, 1),
-    ///     Matrix3x3::new([-6., 1., 6.], [-8., 8., 6.], [-7., -1., 1.],)
-    /// );
-    /// ```
     pub fn submatrix(&self, row: usize, col: usize) -> Matrix3x3 {
         assert!(row < 4);
         assert!(col < 4);
@@ -607,133 +364,16 @@ impl Matrix4x4 {
         self.submatrix(row, col).determinant() * negate
     }
     /// Compute determinant of a 4x4 matrix.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [-2., -8., 3., 5.],
-    ///     [-3., 1., 7., 3.],
-    ///     [1., 2., -9., 6.],
-    ///     [-6., 7., 7., -9.],
-    /// );
-    /// assert_eq!(a.cofactor(0, 0), 690.);
-    /// assert_eq!(a.cofactor(0, 1), 447.);
-    /// assert_eq!(a.cofactor(0, 2), 210.);
-    /// assert_eq!(a.cofactor(0, 3), 51.);
-    /// assert_eq!(a.determinant(), -4071.);
-    /// ```
     pub fn determinant(&self) -> Float {
         (0..4).map(|i| self.cofactor(0, i) * self[(0, i)]).sum()
     }
 
     /// Compute invertibility of matrix (i.e. non-zero determinant.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [6., 4., 4., 4.],
-    ///     [5., 5., 7., 6.],
-    ///     [4., -9., 3., -7.],
-    ///     [9., 1., 7., -6.],
-    /// );
-    /// assert_eq!(a.determinant(), -2120.);
-    /// assert_eq!(a.invertable(), true);
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [-4., 2., -2., -3.],
-    ///     [9., 6., 2., 6.],
-    ///     [0., -5., 1., -5.],
-    ///     [0., 0., 0., 0.],
-    /// );
-    /// assert_eq!(a.determinant(), 0.);
-    /// assert_eq!(a.invertable(), false);
-    /// ```
     pub fn invertable(&self) -> bool {
         self.determinant() != 0.
     }
 
     /// Compute the inverse of a 4x4 matrix.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [-5., 2., 6., -8.],
-    ///     [1., -5., 1., 8.],
-    ///     [7., 7., -6., -7.],
-    ///     [1., -3., 7., 4.],
-    /// );
-    /// let b = a.inverse();
-    ///
-    /// assert_eq!(a.determinant(), 532.);
-    /// assert_eq!(a.cofactor(2, 3), -160.);
-    /// assert_eq!(b[(3, 2)], -160. / 532.);
-    /// assert_eq!(a.cofactor(3, 2), 105.);
-    /// assert_eq!(b[(2, 3)], 105. / 532.);
-    /// assert_eq!(
-    ///     b,
-    ///     Matrix4x4::new(
-    ///         [0.21804512, 0.45112783, 0.24060151, -0.04511278],
-    ///         [-0.8082707, -1.456767, -0.44360903, 0.5206767],
-    ///         [-0.078947365, -0.2236842, -0.05263158, 0.19736843],
-    ///         [-0.52255636, -0.81390977, -0.30075186, 0.30639097]
-    ///     )
-    /// );
-    ///
-    /// // Second test case
-    /// assert_eq!(
-    ///     Matrix4x4::new(
-    ///         [8., -5., 9., 2.],
-    ///         [7., 5., 6., 1.],
-    ///         [-6., 0., 9., 6.],
-    ///         [-3., 0., -9., -4.],
-    ///     )
-    ///     .inverse(),
-    ///     Matrix4x4::new(
-    ///         [-0.15384616, -0.15384616, -0.2820513, -0.53846157],
-    ///         [-0.07692308, 0.12307692, 0.025641026, 0.03076923],
-    ///         [0.35897437, 0.35897437, 0.43589744, 0.9230769],
-    ///         [-0.6923077, -0.6923077, -0.7692308, -1.9230769]
-    ///     ),
-    /// );
-    ///
-    /// // Third test case
-    /// assert_eq!(
-    ///     Matrix4x4::new(
-    ///         [9., 3., 0., 9.],
-    ///         [-5., -2., -6., -3.],
-    ///         [-4., 9., 6., 4.],
-    ///         [-7., 6., 6., 2.],
-    ///     )
-    ///     .inverse(),
-    ///     Matrix4x4::new(
-    ///         [-0.04074074, -0.07777778, 0.14444445, -0.22222222],
-    ///         [-0.07777778, 0.033333335, 0.36666667, -0.33333334],
-    ///         [-0.029012345, -0.14629629, -0.10925926, 0.12962963],
-    ///         [0.17777778, 0.06666667, -0.26666668, 0.33333334]
-    ///     ),
-    /// );
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [3., -9., 7., 3.],
-    ///     [3., -8., 2., -9.],
-    ///     [-4., 4., 4., 1.],
-    ///     [-6., 5., -1., 1.],
-    /// );
-    /// let b = Matrix4x4::new(
-    ///     [8., 2., 2., 2.],
-    ///     [3., -1., 7., 0.],
-    ///     [7., 0., 5., 4.],
-    ///     [6., -2., 0., 5.],
-    /// );
-    /// let c = a * b;
-    /// assert_eq!(c * b.inverse(), a);
-    /// ```
     pub fn inverse(&self) -> Matrix4x4 {
         self.inverse_rtc()
     }
@@ -776,17 +416,6 @@ impl Mul<Matrix4x4> for Matrix4x4 {
     type Output = Matrix4x4;
 
     /// Implement matrix multiplication for `Matrix4x4`.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    ///
-    /// let i = Matrix4x4::identity();
-    /// let m1 = Matrix4x4::identity();
-    /// let m2 = Matrix4x4::identity();
-    ///
-    /// assert_eq!(m1 * m2, i);
-    /// ```
     fn mul(self, m2: Matrix4x4) -> Matrix4x4 {
         let m1 = self;
         let mut r: Matrix4x4 = Default::default();
@@ -806,22 +435,6 @@ impl Mul<Tuple> for Matrix4x4 {
     type Output = Tuple;
 
     /// Implement matrix multiplication for `Matrix4x4` * `Tuple`.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::matrices::Matrix4x4;
-    /// use rtchallenge::tuples::Tuple;
-    ///
-    /// let a = Matrix4x4::new(
-    ///     [1., 2., 3., 4.],
-    ///     [2., 4., 4., 2.],
-    ///     [8., 6., 4., 1.],
-    ///     [0., 0., 0., 1.],
-    /// );
-    /// let b = Tuple::new(1., 2., 3., 1.);
-    ///
-    /// assert_eq!(a * b, Tuple::new(18., 24., 33., 1.));
-    /// ```
     fn mul(self, t: Tuple) -> Tuple {
         let m = self;
         Tuple {
@@ -881,6 +494,235 @@ impl IndexMut<(usize, usize)> for Matrix4x4 {
 mod tests {
     use super::*;
 
+    use crate::{
+        float::consts::PI,
+        tuples::{point, vector},
+    };
+
+    #[test]
+    fn example4x4() {
+        // Individual transformations are applied in sequence.
+        let p = point(1., 0., 1.);
+        let a = Matrix4x4::rotation_x(PI / 2.);
+        let b = Matrix4x4::scaling(5., 5., 5.);
+        let c = Matrix4x4::translation(10., 5., 7.);
+        // Apply rotation first.
+        let p2 = a * p;
+        assert_eq!(p2, point(1., -1., 0.));
+        // Then apply scaling.
+        let p3 = b * p2;
+        assert_eq!(p3, point(5., -5., 0.));
+        // Then apply translation.
+        let p4 = c * p3;
+        assert_eq!(p4, point(15., 0., 7.));
+
+        // Chained transformations must be applied in reverse order.
+        let p = point(1., 0., 1.);
+        let a = Matrix4x4::rotation_x(PI / 2.);
+        let b = Matrix4x4::scaling(5., 5., 5.);
+        let c = Matrix4x4::translation(10., 5., 7.);
+        let t = c * b * a;
+        assert_eq!(t * p, point(15., 0., 7.));
+    }
+
+    #[test]
+    fn translation() {
+        let transform = Matrix4x4::translation(5., -3., 2.);
+        let p = point(-3., 4., 5.);
+        assert_eq!(transform * p, point(2., 1., 7.));
+
+        let inv = transform.inverse();
+        assert_eq!(inv * p, point(-8., 7., 3.));
+
+        let v = vector(-3., 4., 5.);
+        assert_eq!(transform * v, v);
+    }
+    #[test]
+    fn scaling() {
+        // A scaling matrix applied to a point.
+        let transform = Matrix4x4::scaling(2., 3., 4.);
+        let p = point(-4., 6., 8.);
+        assert_eq!(transform * p, point(-8., 18., 32.));
+
+        // A scaling matrix applied to a vector.
+        let v = vector(-4., 6., 8.);
+        assert_eq!(transform * v, vector(-8., 18., 32.));
+
+        // Multiplying by the inverse of a scaling matrix.
+        let inv = transform.inverse();
+        assert_eq!(inv * v, vector(-2., 2., 2.));
+
+        // Reflection is scaling by a negative value.
+        let transform = Matrix4x4::scaling(-1., 1., 1.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(-2., 3., 4.));
+    }
+    #[test]
+    fn rotation_x() {
+        // A scaling matrix applied to a point.
+        let p = point(0., 1., 0.);
+        let half_quarter = Matrix4x4::rotation_x(PI / 4.);
+        let full_quarter = Matrix4x4::rotation_x(PI / 2.);
+
+        assert_eq!(
+            half_quarter * p,
+            point(0., (2.0 as Float).sqrt() / 2., (2.0 as Float).sqrt() / 2.)
+        );
+        assert_eq!(full_quarter * p, point(0., 0., 1.),);
+    }
+    #[test]
+    fn rotation_y() {
+        // A scaling matrix applied to a point.
+        let p = point(0., 0., 1.);
+        let half_quarter = Matrix4x4::rotation_y(PI / 4.);
+        let full_quarter = Matrix4x4::rotation_y(PI / 2.);
+
+        assert_eq!(
+            half_quarter * p,
+            point((2.0 as Float).sqrt() / 2., 0., (2.0 as Float).sqrt() / 2.)
+        );
+        assert_eq!(full_quarter * p, point(1., 0., 0.,),);
+    }
+    #[test]
+    fn rotation_z() {
+        // A scaling matrix applied to a point.
+        let p = point(0., 1., 0.);
+        let half_quarter = Matrix4x4::rotation_z(PI / 4.);
+        let full_quarter = Matrix4x4::rotation_z(PI / 2.);
+
+        assert_eq!(
+            half_quarter * p,
+            point(-(2.0 as Float).sqrt() / 2., (2.0 as Float).sqrt() / 2., 0.)
+        );
+        assert_eq!(full_quarter * p, point(-1., 0., 0.,),);
+    }
+    #[test]
+    fn transpose() {
+        let m = Matrix4x4::new(
+            [2., 0., 0., 0.],
+            [3., 1., 0., 0.],
+            [4., 0., 1., 0.],
+            [5., 6., 7., 1.],
+        );
+        let m_t = Matrix4x4::new(
+            [2., 3., 4., 5.],
+            [0., 1., 0., 6.],
+            [0., 0., 1., 7.],
+            [0., 0., 0., 1.],
+        );
+        assert_eq!(m.transpose(), m_t);
+
+        assert_eq!(Matrix4x4::identity(), Matrix4x4::identity().transpose());
+    }
+    #[test]
+    fn shearing() {
+        // A shearing transform moves x in proportion to y.
+        let transform = Matrix4x4::shearing(1., 0., 0., 0., 0., 0.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(5., 3., 4.));
+
+        // A shearing transform moves x in proportion to z.
+        let transform = Matrix4x4::shearing(0., 1., 0., 0., 0., 0.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(6., 3., 4.));
+
+        // A shearing transform moves y in proportion to x.
+        let transform = Matrix4x4::shearing(0., 0., 1., 0., 0., 0.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(2., 5., 4.));
+
+        // A shearing transform moves y in proportion to z.
+        let transform = Matrix4x4::shearing(0., 0., 0., 1., 0., 0.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(2., 7., 4.));
+
+        // A shearing transform moves z in proportion to x.
+        let transform = Matrix4x4::shearing(0., 0., 0., 0., 1., 0.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(2., 3., 6.));
+
+        // A shearing transform moves z in proportion to y.
+        let transform = Matrix4x4::shearing(0., 0., 0., 0., 0., 1.);
+        let p = point(2., 3., 4.);
+        assert_eq!(transform * p, point(2., 3., 7.));
+    }
+    #[test]
+    fn inverse_rtiow() {
+        let i = Matrix4x4::identity();
+        assert_eq!(i.inverse_rtiow() * i, i);
+
+        let m = Matrix4x4::new(
+            [2., 0., 0., 0.],
+            [0., 3., 0., 0.],
+            [0., 0., 4., 0.],
+            [0., 0., 0., 1.],
+        );
+        assert_eq!(m.inverse_rtiow() * m, i);
+        assert_eq!(m * m.inverse_rtiow(), i);
+    }
+    #[test]
+    fn determinant_2x2() {
+        let a = Matrix2x2::new([1., 5.], [-3., 2.]);
+
+        assert_eq!(a.determinant(), 17.);
+    }
+    #[test]
+    fn determinant_3x3() {
+        let a = Matrix3x3::new([1., 2., 6.], [-5., 8., -4.], [2., 6., 4.]);
+        assert_eq!(a.cofactor(0, 0), 56.);
+        assert_eq!(a.cofactor(0, 1), 12.);
+        assert_eq!(a.cofactor(0, 2), -46.);
+        assert_eq!(a.determinant(), -196.);
+    }
+    #[test]
+    fn determinant_4x4() {
+        let a = Matrix4x4::new(
+            [-2., -8., 3., 5.],
+            [-3., 1., 7., 3.],
+            [1., 2., -9., 6.],
+            [-6., 7., 7., -9.],
+        );
+        assert_eq!(a.cofactor(0, 0), 690.);
+        assert_eq!(a.cofactor(0, 1), 447.);
+        assert_eq!(a.cofactor(0, 2), 210.);
+        assert_eq!(a.cofactor(0, 3), 51.);
+        assert_eq!(a.determinant(), -4071.);
+    }
+    #[test]
+    fn submatrix_3x3() {
+        assert_eq!(
+            Matrix3x3::new([1., 5., 0.], [-3., 2., 7.], [0., 6., -3.],).submatrix(0, 2),
+            Matrix2x2::new([-3., 2.], [0., 6.])
+        );
+    }
+    #[test]
+    fn submatrix_4x4() {
+        assert_eq!(
+            Matrix4x4::new(
+                [-6., 1., 1., 6.],
+                [-8., 5., 8., 6.],
+                [-1., 0., 8., 2.],
+                [-7., 1., -1., 1.],
+            )
+            .submatrix(2, 1),
+            Matrix3x3::new([-6., 1., 6.], [-8., 8., 6.], [-7., -1., 1.],)
+        );
+    }
+    #[test]
+    fn minor_3x3() {
+        let a = Matrix3x3::new([3., 5., 0.], [2., -1., -7.], [6., -1., 5.]);
+        let b = a.submatrix(1, 0);
+        assert_eq!(b.determinant(), 25.0);
+        assert_eq!(b.determinant(), a.minor(1, 0));
+    }
+    #[test]
+    fn cofactor_3x3() {
+        let a = Matrix3x3::new([3., 5., 0.], [2., -1., -7.], [6., -1., 5.]);
+        assert_eq!(a.minor(0, 0), -12.);
+        assert_eq!(a.cofactor(0, 0), -12.);
+        assert_eq!(a.minor(1, 0), 25.);
+        assert_eq!(a.cofactor(1, 0), -25.);
+    }
     #[test]
     fn construct2x2() {
         let m = Matrix2x2::new([-3., 5.], [1., -2.]);
@@ -899,6 +741,100 @@ mod tests {
         assert_eq!(m[(2, 2)], 1.);
     }
     #[test]
+    fn invertable() {
+        let a = Matrix4x4::new(
+            [6., 4., 4., 4.],
+            [5., 5., 7., 6.],
+            [4., -9., 3., -7.],
+            [9., 1., 7., -6.],
+        );
+        assert_eq!(a.determinant(), -2120.);
+        assert_eq!(a.invertable(), true);
+
+        let a = Matrix4x4::new(
+            [-4., 2., -2., -3.],
+            [9., 6., 2., 6.],
+            [0., -5., 1., -5.],
+            [0., 0., 0., 0.],
+        );
+        assert_eq!(a.determinant(), 0.);
+        assert_eq!(a.invertable(), false);
+    }
+    #[test]
+    fn inverse() {
+        let a = Matrix4x4::new(
+            [-5., 2., 6., -8.],
+            [1., -5., 1., 8.],
+            [7., 7., -6., -7.],
+            [1., -3., 7., 4.],
+        );
+        let b = a.inverse();
+
+        assert_eq!(a.determinant(), 532.);
+        assert_eq!(a.cofactor(2, 3), -160.);
+        assert_eq!(b[(3, 2)], -160. / 532.);
+        assert_eq!(a.cofactor(3, 2), 105.);
+        assert_eq!(b[(2, 3)], 105. / 532.);
+        assert_eq!(
+            b,
+            Matrix4x4::new(
+                [0.21804512, 0.45112783, 0.24060151, -0.04511278],
+                [-0.8082707, -1.456767, -0.44360903, 0.5206767],
+                [-0.078947365, -0.2236842, -0.05263158, 0.19736843],
+                [-0.52255636, -0.81390977, -0.30075186, 0.30639097]
+            )
+        );
+
+        // Second test case
+        assert_eq!(
+            Matrix4x4::new(
+                [8., -5., 9., 2.],
+                [7., 5., 6., 1.],
+                [-6., 0., 9., 6.],
+                [-3., 0., -9., -4.],
+            )
+            .inverse(),
+            Matrix4x4::new(
+                [-0.15384616, -0.15384616, -0.2820513, -0.53846157],
+                [-0.07692308, 0.12307692, 0.025641026, 0.03076923],
+                [0.35897437, 0.35897437, 0.43589744, 0.9230769],
+                [-0.6923077, -0.6923077, -0.7692308, -1.9230769]
+            ),
+        );
+
+        // Third test case
+        assert_eq!(
+            Matrix4x4::new(
+                [9., 3., 0., 9.],
+                [-5., -2., -6., -3.],
+                [-4., 9., 6., 4.],
+                [-7., 6., 6., 2.],
+            )
+            .inverse(),
+            Matrix4x4::new(
+                [-0.04074074, -0.07777778, 0.14444445, -0.22222222],
+                [-0.07777778, 0.033333335, 0.36666667, -0.33333334],
+                [-0.029012345, -0.14629629, -0.10925926, 0.12962963],
+                [0.17777778, 0.06666667, -0.26666668, 0.33333334]
+            ),
+        );
+
+        let a = Matrix4x4::new(
+            [3., -9., 7., 3.],
+            [3., -8., 2., -9.],
+            [-4., 4., 4., 1.],
+            [-6., 5., -1., 1.],
+        );
+        let b = Matrix4x4::new(
+            [8., 2., 2., 2.],
+            [3., -1., 7., 0.],
+            [7., 0., 5., 4.],
+            [6., -2., 0., 5.],
+        );
+        let c = a * b;
+        assert_eq!(c * b.inverse(), a);
+    }
+    #[test]
     fn construct4x4() {
         let m = Matrix4x4::new(
             [1., 2., 3., 4.],
@@ -971,4 +907,16 @@ mod tests {
             )
         );
     }
+    #[test]
+    fn mul4x4_tuple() {
+        let a = Matrix4x4::new(
+            [1., 2., 3., 4.],
+            [2., 4., 4., 2.],
+            [8., 6., 4., 1.],
+            [0., 0., 0., 1.],
+        );
+        let b = Tuple::new(1., 2., 3., 1.);
+
+        assert_eq!(a * b, Tuple::new(18., 24., 33., 1.));
+    }
 }

rtchallenge/src/patterns.rs

@@ -0,0 +1,444 @@
+use derive_builder::Builder;
+
+use crate::{
+    matrices::Matrix4x4,
+    shapes::Shape,
+    tuples::{Color, Tuple},
+    BLACK, WHITE,
+};
+
+pub const BLACK_PAT: Pattern = Pattern {
+    color: ColorMapper::Constant(BLACK),
+    transform: Matrix4x4::identity(),
+    inverse_transform: Matrix4x4::identity(),
+};
+pub const WHITE_PAT: Pattern = Pattern {
+    color: ColorMapper::Constant(WHITE),
+    transform: Matrix4x4::identity(),
+    inverse_transform: Matrix4x4::identity(),
+};
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum ColorMapper {
+    /// TestPattern the color returned is the pattern space point after going through world->object and object->pattern space translation.
+    TestPattern,
+    /// Solid color, the same sampled every where.
+    Constant(Color),
+    /// Pattern that alternates between the given patterns along each unit of the X-axis.  The
+    /// strip extends infinitely in the positive and negative Y and Z axes.
+    Stripe { a: Box<Pattern>, b: Box<Pattern> },
+    /// Linear blend between `a` and `b` along the X-axis.
+    Gradient { a: Box<Pattern>, b: Box<Pattern> },
+    /// Bullseye pattern in the XZ plane.
+    Ring { a: Box<Pattern>, b: Box<Pattern> },
+    /// Traditional ray tracer tile floor pattern.
+    Checkers { a: Box<Pattern>, b: Box<Pattern> },
+}
+
+impl From<Color> for ColorMapper {
+    fn from(c: Color) -> ColorMapper {
+        ColorMapper::Constant(c)
+    }
+}
+
+impl From<Color> for Box<Pattern> {
+    fn from(c: Color) -> Box<Pattern> {
+        Box::new(Pattern {
+            color: ColorMapper::Constant(c),
+            ..Pattern::default()
+        })
+    }
+}
+
+#[derive(Builder, Debug, PartialEq, Clone)]
+#[builder(default, pattern = "immutable")]
+pub struct Pattern {
+    pub color: ColorMapper,
+    transform: Matrix4x4,
+    #[builder(private, default = "self.default_inverse_transform()?")]
+    inverse_transform: Matrix4x4,
+}
+
+impl PatternBuilder {
+    fn default_inverse_transform(&self) -> Result<Matrix4x4, String> {
+        Ok(self.transform.unwrap_or(Matrix4x4::identity()).inverse())
+    }
+}
+
+impl Default for Pattern {
+    fn default() -> Pattern {
+        Pattern {
+            color: ColorMapper::Constant(WHITE),
+            transform: Matrix4x4::identity(),
+            inverse_transform: Matrix4x4::identity(),
+        }
+    }
+}
+
+/// Creates a [Pattern] with a color type of [ColorMapper::Constant] from the given [Color]
+impl<C> From<C> for Pattern
+where
+    C: Into<Color>,
+{
+    fn from(c: C) -> Self {
+        Pattern {
+            color: ColorMapper::Constant(c.into()),
+            ..Pattern::default()
+        }
+    }
+}
+
+/// Builder for creating a material pattern used for testing.  The color returned is the pattern space point
+/// after going through world->object and object->pattern space translation.
+pub fn test_pattern() -> PatternBuilder {
+    PatternBuilder::default().color(ColorMapper::TestPattern)
+}
+
+/// Builder for creating a material pattern that alternates between the given colors along each unit of the
+/// X-axis.  The strip extends infinitely in the positive and negative Y and Z axes.
+pub fn stripe_pattern(a: Pattern, b: Pattern) -> PatternBuilder {
+    PatternBuilder::default().color(ColorMapper::Stripe {
+        a: a.into(),
+        b: b.into(),
+    })
+}
+
+/// Builder for creating a material pattern that gradually blends between the given colors along
+/// the X-axis.
+pub fn gradient_pattern(a: Pattern, b: Pattern) -> PatternBuilder {
+    PatternBuilder::default().color(ColorMapper::Gradient {
+        a: a.into(),
+        b: b.into(),
+    })
+}
+
+/// Builder for creating a material pattern that alternates between the given colors in a ring
+/// shape in the XZ plane.
+pub fn ring_pattern(a: Pattern, b: Pattern) -> PatternBuilder {
+    PatternBuilder::default().color(ColorMapper::Ring {
+        a: a.into(),
+        b: b.into(),
+    })
+}
+
+/// Builder for creating a material pattern that alternates between the given colors along the X, Y
+/// and Z pattern.  Creates traditional ray tracer tile floor pattern.
+pub fn checkers_pattern(a: Pattern, b: Pattern) -> PatternBuilder {
+    PatternBuilder::default().color(ColorMapper::Checkers {
+        a: a.into(),
+        b: b.into(),
+    })
+}
+
+/// Generic implementation for mapping points to colors according to the given [ColorMapper].
+impl Pattern {
+    /// Create a pattern used for testing.  The color returned is the pattern space point
+    /// after going through world->object and object->pattern space translation.
+    pub fn test() -> Pattern {
+        Pattern {
+            color: ColorMapper::TestPattern,
+            ..Pattern::default()
+        }
+    }
+
+    /// Create a pattern that alternates between the given Patterns along each unit of the
+    /// X-axis.  The strip extends infinitely in the positive and negative Y and Z axes.
+    pub fn stripe(a: Pattern, b: Pattern) -> Pattern {
+        Pattern {
+            color: ColorMapper::Stripe {
+                a: a.into(),
+                b: b.into(),
+            },
+            ..Pattern::default()
+        }
+    }
+
+    /// Create a pattern that gradually blends between the given Patterns along the X-axis.
+    pub fn gradient(a: Pattern, b: Pattern) -> Pattern {
+        Pattern {
+            color: ColorMapper::Gradient {
+                a: a.into(),
+                b: b.into(),
+            },
+            ..Pattern::default()
+        }
+    }
+
+    /// Create a pattern that alternates between the given Patterns in a ring in the XZ plane.
+    pub fn ring(a: Pattern, b: Pattern) -> Pattern {
+        Pattern {
+            color: ColorMapper::Ring {
+                a: a.into(),
+                b: b.into(),
+            },
+            ..Pattern::default()
+        }
+    }
+
+    /// Create a pattern that alternates between the given Patterns along the X, Y and Z axis.
+    pub fn checkers(a: Pattern, b: Pattern) -> Pattern {
+        Pattern {
+            color: ColorMapper::Checkers {
+                a: a.into(),
+                b: b.into(),
+            },
+            ..Pattern::default()
+        }
+    }
+
+    /// Sample the color at the given point in untranslated object space.
+    pub fn pattern_at(&self, object_point: Tuple) -> Color {
+        let point = self.inverse_transform * object_point;
+        match &self.color {
+            ColorMapper::TestPattern => [point.x, point.y, point.z].into(),
+            ColorMapper::Constant(c) => *c,
+            ColorMapper::Stripe { a, b } => {
+                let x = point.x.floor();
+                if x % 2. == 0. {
+                    a.pattern_at(point)
+                } else {
+                    b.pattern_at(point)
+                }
+            }
+            ColorMapper::Gradient { a, b } => {
+                let a = a.pattern_at(point);
+                let b = b.pattern_at(point);
+                let distance = b - a;
+                let fraction = point.x - point.x.floor();
+                a + distance * fraction
+            }
+            ColorMapper::Ring { a, b } => {
+                let a = a.pattern_at(point);
+                let b = b.pattern_at(point);
+                let px = point.x;
+                let pz = point.z;
+                if (px * px + pz * pz).sqrt().floor() % 2. == 0. {
+                    a
+                } else {
+                    b
+                }
+            }
+            ColorMapper::Checkers { a, b } => {
+                let a = a.pattern_at(point);
+                let b = b.pattern_at(point);
+                let d = point.x.floor() + point.y.floor() + point.z.floor();
+                if d % 2. == 0. {
+                    a
+                } else {
+                    b
+                }
+            }
+        }
+    }
+    /// Sample the color at the given world point on the given object.
+    /// This function respects the object and the pattern's transform matrix.
+    pub fn pattern_at_object(&self, object: &Shape, world_point: Tuple) -> Color {
+        let object_point = object.inverse_transform() * world_point;
+        self.pattern_at(object_point)
+    }
+    pub fn transform(&self) -> Matrix4x4 {
+        self.transform
+    }
+
+    pub fn inverse_transform(&self) -> Matrix4x4 {
+        self.inverse_transform
+    }
+
+    pub fn set_transform(&mut self, t: Matrix4x4) {
+        self.transform = t;
+        self.inverse_transform = t.inverse();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        matrices::identity,
+        patterns::{ColorMapper, Pattern, BLACK_PAT, WHITE_PAT},
+        BLACK, WHITE,
+    };
+
+    #[test]
+    fn test_create() {
+        let pattern = Pattern::test();
+        assert_eq!(pattern.transform(), identity());
+    }
+
+    #[test]
+    fn stripe_create() {
+        let pattern = Pattern::stripe(BLACK_PAT, WHITE_PAT);
+        assert_eq!(
+            pattern.color,
+            ColorMapper::Stripe {
+                a: BLACK.into(),
+                b: WHITE.into(),
+            }
+        );
+    }
+    #[test]
+    fn gradient_create() {
+        println!("SHOE ME SOMETHING");
+        println!("* * * 1");
+        let pattern = Pattern::gradient(BLACK_PAT, WHITE_PAT);
+        println!("* * * 2");
+        assert_eq!(
+            pattern.color,
+            ColorMapper::Gradient {
+                a: BLACK.into(),
+                b: WHITE.into(),
+            }
+        );
+    }
+    #[test]
+    fn ring_create() {
+        let pattern = Pattern::ring(BLACK_PAT, WHITE_PAT);
+        assert_eq!(
+            pattern.color,
+            ColorMapper::Ring {
+                a: BLACK.into(),
+                b: WHITE.into()
+            }
+        );
+    }
+    #[test]
+    fn checkers_create() {
+        let pattern = Pattern::checkers(BLACK_PAT, WHITE_PAT);
+        assert_eq!(
+            pattern.color,
+            ColorMapper::Checkers {
+                a: BLACK.into(),
+                b: WHITE.into()
+            }
+        );
+    }
+
+    mod pattern_at {
+        use super::*;
+        use crate::tuples::point;
+
+        #[test]
+        fn test_returns_coordinates() {
+            // A test returns the pattern space coordinates of the point.
+            let pattern = Pattern::test();
+            let p = point(1., 2., 3.);
+            assert_eq!(pattern.pattern_at(p), [p.x, p.y, p.z].into());
+        }
+
+        #[test]
+        fn stripe_alternates_between_two_colors() {
+            // A stripe alternates between two colors.
+            let pattern = Pattern::stripe(WHITE_PAT, BLACK_PAT);
+            for (p, want) in &[
+                // A stripe pattern is constant in y.
+                (point(0., 0., 0.), WHITE),
+                (point(0., 1., 0.), WHITE),
+                (point(0., 2., 0.), WHITE),
+                // A stripe pattern is constant in z.
+                (point(0., 0., 0.), WHITE),
+                (point(0., 0., 1.), WHITE),
+                (point(0., 0., 2.), WHITE),
+                // A stripe pattern alternates in z.
+                (point(0., 0., 0.), WHITE),
+                (point(0.9, 0., 0.), WHITE),
+                (point(1., 0., 0.), BLACK),
+                (point(-0.1, 0., 0.), BLACK),
+                (point(-1., 0., 0.), BLACK),
+                (point(-1.1, 0., 0.), WHITE),
+            ] {
+                assert_eq!(pattern.pattern_at(*p), *want, "{:?}", p);
+            }
+        }
+
+        #[test]
+        fn gradient_linearly_interpolates_between_colors() {
+            // A gradient linearly interpolates between two colors.
+            let pattern = Pattern::gradient(WHITE_PAT, BLACK_PAT);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.)), WHITE);
+            assert_eq!(
+                pattern.pattern_at(point(0.25, 0., 0.)),
+                [0.75, 0.75, 0.75].into()
+            );
+            assert_eq!(
+                pattern.pattern_at(point(0.5, 0., 0.)),
+                [0.5, 0.5, 0.5].into()
+            );
+            assert_eq!(
+                pattern.pattern_at(point(0.75, 0., 0.)),
+                [0.25, 0.25, 0.25].into()
+            );
+        }
+
+        #[test]
+        fn ring_extend_in_x_and_z() {
+            // A ring should extend both in x and z.
+            let pattern = Pattern::ring(WHITE_PAT, BLACK_PAT);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(1., 0., 0.)), BLACK);
+            assert_eq!(pattern.pattern_at(point(0., 0., 1.)), BLACK);
+            // 0.708 is slight more than 2.sqrt()/2.
+            assert_eq!(pattern.pattern_at(point(0.708, 0., 0.708)), BLACK);
+        }
+
+        #[test]
+        fn checkers_repeat_along_x_axis() {
+            // Checkers should repeat along X-axis.
+            let pattern = Pattern::checkers(WHITE_PAT, BLACK_PAT);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(0.99, 0., 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(1.01, 0., 0.)), BLACK);
+        }
+
+        #[test]
+        fn checkers_repeat_along_y_axis() {
+            // Checkers should repeat along Y-axis.
+            let pattern = Pattern::checkers(WHITE_PAT, BLACK_PAT);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(0., 0.99, 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(0., 1.01, 0.)), BLACK);
+        }
+
+        #[test]
+        fn checkers_repeat_along_z_axis() {
+            // Checkers should repeat along Z-axis.
+            let pattern = Pattern::checkers(WHITE_PAT, BLACK_PAT);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.)), WHITE);
+            assert_eq!(pattern.pattern_at(point(0., 0., 0.99)), WHITE);
+            assert_eq!(pattern.pattern_at(point(0., 0., 1.01)), BLACK);
+        }
+    }
+
+    mod pattern_at_object {
+        use std::error::Error;
+
+        use crate::{
+            matrices::scaling,
+            patterns::{stripe_pattern, BLACK_PAT, WHITE_PAT},
+            shapes::{Shape, ShapeBuilder},
+            tuples::point,
+            WHITE,
+        };
+
+        #[test]
+        fn stripes_with_an_object_transformation() -> Result<(), Box<dyn Error>> {
+            // Stripes with an object transformation.
+            let object = ShapeBuilder::sphere()
+                .transform(scaling(2., 2., 2.))
+                .build()?;
+            let pattern = stripe_pattern(WHITE_PAT, BLACK_PAT).build()?;
+            let c = pattern.pattern_at_object(&object, point(1.5, 0., 0.));
+            assert_eq!(c, WHITE);
+            Ok(())
+        }
+
+        #[test]
+        fn stripes_with_a_pattern_transformation() -> Result<(), Box<dyn Error>> {
+            // Stripes with a pattern transformation.
+            let object = Shape::sphere();
+            let mut pattern = stripe_pattern(WHITE_PAT, BLACK_PAT).build()?;
+            pattern.set_transform(scaling(2., 2., 2.));
+            let c = pattern.pattern_at_object(&object, point(1.5, 0., 0.));
+            assert_eq!(c, WHITE);
+            Ok(())
+        }
+    }
+}

rtchallenge/src/rays.rs

@@ -1,6 +1,7 @@
 use crate::{matrices::Matrix4x4, tuples::Tuple, Float};
 
 /// Rays have an origin and a direction. This datatype is the 'ray' in 'raytracer'.
+#[derive(Debug, Default, Clone, PartialEq)]
 pub struct Ray {
     pub origin: Tuple,
     pub direction: Tuple,
@@ -9,17 +10,6 @@ pub struct Ray {
 impl Ray {
     /// Create a ray with the given origin point and direction vector.
     /// Will panic if origin not a point or direction not a vector.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{rays::Ray, tuples::Tuple};
-    ///
-    /// let origin = Tuple::point(1., 2., 3.);
-    /// let direction = Tuple::vector(4., 5., 6.);
-    /// let r = Ray::new(origin, direction);
-    /// assert_eq!(r.origin, origin);
-    /// assert_eq!(r.direction, direction);
-    /// ```
     pub fn new(origin: Tuple, direction: Tuple) -> Ray {
         assert!(origin.is_point(), "Ray origin must be a point");
         assert!(direction.is_vector(), "Ray direction must be a vector");
@@ -27,41 +17,11 @@ impl Ray {
     }
 
     /// Compute a point from the given distance along the `Ray`.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{rays::Ray, tuples::Tuple};
-    ///
-    /// let r = Ray::new(Tuple::point(2., 3., 4.), Tuple::vector(1., 0., 0.));
-    /// assert_eq!(r.position(0.), Tuple::point(2., 3., 4.));
-    /// assert_eq!(r.position(1.), Tuple::point(3., 3., 4.));
-    /// assert_eq!(r.position(-1.), Tuple::point(1., 3., 4.));
-    /// assert_eq!(r.position(2.5), Tuple::point(4.5, 3., 4.));
-    /// ```
     pub fn position(&self, t: Float) -> Tuple {
         self.origin + self.direction * t
     }
 
     /// Apply Matrix4x4 transforms to Ray.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{matrices::Matrix4x4, rays::Ray, tuples::Tuple};
-    ///
-    /// // Translating a ray
-    /// let r = Ray::new(Tuple::point(1., 2., 3.), Tuple::vector(0., 1., 0.));
-    /// let m = Matrix4x4::translation(3., 4., 5.);
-    /// let r2 = r.transform(m);
-    /// assert_eq!(r2.origin, Tuple::point(4., 6., 8.));
-    /// assert_eq!(r2.direction, Tuple::vector(0., 1., 0.));
-    ///
-    /// // Scaling a ray
-    /// let r = Ray::new(Tuple::point(1., 2., 3.), Tuple::vector(0., 1., 0.));
-    /// let m = Matrix4x4::scaling(2., 3., 4.);
-    /// let r2 = r.transform(m);
-    /// assert_eq!(r2.origin, Tuple::point(2., 6., 12.));
-    /// assert_eq!(r2.direction, Tuple::vector(0., 3., 0.));
-    /// ```
     pub fn transform(&self, m: Matrix4x4) -> Ray {
         Ray {
             origin: m * self.origin,
@@ -69,3 +29,46 @@ impl Ray {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        matrices::Matrix4x4,
+        rays::Ray,
+        tuples::{point, vector},
+    };
+    #[test]
+    fn create() {
+        let origin = point(1., 2., 3.);
+        let direction = vector(4., 5., 6.);
+        let r = Ray::new(origin, direction);
+        assert_eq!(r.origin, origin);
+        assert_eq!(r.direction, direction);
+    }
+    #[test]
+    fn position() {
+        let r = Ray::new(point(2., 3., 4.), vector(1., 0., 0.));
+        assert_eq!(r.position(0.), point(2., 3., 4.));
+        assert_eq!(r.position(1.), point(3., 3., 4.));
+        assert_eq!(r.position(-1.), point(1., 3., 4.));
+        assert_eq!(r.position(2.5), point(4.5, 3., 4.));
+    }
+    #[test]
+    fn transform_translating_ray() {
+        // Translating a ray
+        let r = Ray::new(point(1., 2., 3.), vector(0., 1., 0.));
+        let m = Matrix4x4::translation(3., 4., 5.);
+        let r2 = r.transform(m);
+        assert_eq!(r2.origin, point(4., 6., 8.));
+        assert_eq!(r2.direction, vector(0., 1., 0.));
+    }
+    #[test]
+    fn transform_scaling_ray() {
+        // Scaling a ray
+        let r = Ray::new(point(1., 2., 3.), vector(0., 1., 0.));
+        let m = Matrix4x4::scaling(2., 3., 4.);
+        let r2 = r.transform(m);
+        assert_eq!(r2.origin, point(2., 6., 12.));
+        assert_eq!(r2.direction, vector(0., 3., 0.));
+    }
+}

rtchallenge/src/transformations.rs

@@ -5,47 +5,6 @@ use crate::{
 
 /// Create a matrix representing a eye at `from` looking at `to`, with an `up`
 /// as the up vector.
-///
-/// # Examples
-/// ```
-/// use rtchallenge::{matrices::Matrix4x4, transformations::view_transform, tuples::Tuple};
-///
-/// // The transofrmation matrix for the default orientation.
-/// let from = Tuple::point(0., 0., 0.);
-/// let to = Tuple::point(0., 0., -1.);
-/// let up = Tuple::vector(0., 1., 0.);
-/// let t = view_transform(from, to, up);
-/// assert_eq!(t, Matrix4x4::identity());
-///
-/// // A view transformation matrix looking in positive z direction.
-/// let from = Tuple::point(0., 0., 0.);
-/// let to = Tuple::point(0., 0., 1.);
-/// let up = Tuple::vector(0., 1., 0.);
-/// let t = view_transform(from, to, up);
-/// assert_eq!(t, Matrix4x4::scaling(-1., 1., -1.));
-///
-/// // The view tranformation moves the world.
-/// let from = Tuple::point(0., 0., 8.);
-/// let to = Tuple::point(0., 0., 0.);
-/// let up = Tuple::vector(0., 1., 0.);
-/// let t = view_transform(from, to, up);
-/// assert_eq!(t, Matrix4x4::translation(0., 0., -8.));
-///
-/// // An arbitrary view transformation.
-/// let from = Tuple::point(1., 3., 2.);
-/// let to = Tuple::point(4., -2., 8.);
-/// let up = Tuple::vector(1., 1., 0.);
-/// let t = view_transform(from, to, up);
-/// assert_eq!(
-///     t,
-///     Matrix4x4::new(
-///         [-0.50709, 0.50709, 0.67612, -2.36643],
-///         [0.76772, 0.60609, 0.12122, -2.82843],
-///         [-0.35857, 0.59761, -0.71714, 0.],
-///         [0., 0., 0., 1.],
-///     )
-/// );
-/// ```
 pub fn view_transform(from: Tuple, to: Tuple, up: Tuple) -> Matrix4x4 {
     let forward = (to - from).normalize();
     let left = cross(forward, up.normalize());
@@ -57,3 +16,56 @@ pub fn view_transform(from: Tuple, to: Tuple, up: Tuple) -> Matrix4x4 {
         [0., 0., 0., 1.],
     ) * Matrix4x4::translation(-from.x, -from.y, -from.z)
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        matrices::{identity, scaling, translation, Matrix4x4},
+        transformations::view_transform,
+        tuples::{point, vector},
+    };
+    #[test]
+    fn default_orientation() {
+        // The transformation matrix for the default orientation.
+        let from = point(0., 0., 0.);
+        let to = point(0., 0., -1.);
+        let up = vector(0., 1., 0.);
+        let t = view_transform(from, to, up);
+        assert_eq!(t, identity());
+    }
+    #[test]
+    fn looking_positive_z() {
+        // A view transformation matrix looking in positive z direction.
+        let from = point(0., 0., 0.);
+        let to = point(0., 0., 1.);
+        let up = vector(0., 1., 0.);
+        let t = view_transform(from, to, up);
+        assert_eq!(t, scaling(-1., 1., -1.));
+    }
+    #[test]
+    fn transformation_moves_world() {
+        // The view transformation moves the world.
+        let from = point(0., 0., 8.);
+        let to = point(0., 0., 0.);
+        let up = vector(0., 1., 0.);
+        let t = view_transform(from, to, up);
+        assert_eq!(t, translation(0., 0., -8.));
+    }
+    #[test]
+    fn arbitrary_view() {
+        // An arbitrary view transformation.
+        let from = point(1., 3., 2.);
+        let to = point(4., -2., 8.);
+        let up = vector(1., 1., 0.);
+        let t = view_transform(from, to, up);
+        assert_eq!(
+            t,
+            Matrix4x4::new(
+                [-0.50709, 0.50709, 0.67612, -2.36643],
+                [0.76772, 0.60609, 0.12122, -2.82843],
+                [-0.35857, 0.59761, -0.71714, 0.],
+                [0., 0., 0., 1.],
+            )
+        );
+    }
+}

rtchallenge/src/tuples.rs

@@ -2,7 +2,17 @@ use std::ops::{Add, Div, Mul, Neg, Sub};
 
 use crate::{Float, EPSILON};
 
-#[derive(Debug, Copy, Clone)]
+/// Short hand for creating a Tuple that represents a point, w=1.
+pub fn point(x: Float, y: Float, z: Float) -> Tuple {
+    Tuple::point(x, y, z)
+}
+
+/// Short hand for creating a Tuple that represents a vector, w=0.
+pub fn vector(x: Float, y: Float, z: Float) -> Tuple {
+    Tuple::vector(x, y, z)
+}
+
+#[derive(Debug, Default, Copy, Clone)]
 pub struct Tuple {
     pub x: Float,
     pub y: Float,
@@ -47,26 +57,6 @@ impl Tuple {
 }
 
 /// Reflects vector v across normal n.
-///
-/// # Examples
-/// ```
-/// use rtchallenge::{
-///     tuples::{reflect, Tuple},
-///     Float,
-/// };
-///
-/// // Reflecting a vector approaching at 45°
-/// let v = Tuple::vector(1., -1., 0.);
-/// let n = Tuple::vector(0., 1., 0.);
-/// let r = reflect(v, n);
-/// assert_eq!(r, Tuple::vector(1., 1., 0.));
-///
-/// // Reflecting off a slanted surface.
-/// let v = Tuple::vector(0., -1., 0.);
-/// let n = Tuple::vector((2. as Float).sqrt() / 2., (2. as Float).sqrt() / 2., 0.);
-/// let r = reflect(v, n);
-/// assert_eq!(r, Tuple::vector(1., 0., 0.));
-/// ```
 pub fn reflect(v: Tuple, n: Tuple) -> Tuple {
     v - n * 2. * dot(v, n)
 }
@@ -161,17 +151,29 @@ pub fn cross(a: Tuple, b: Tuple) -> Tuple {
     )
 }
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Default)]
 pub struct Color {
     pub red: Float,
     pub green: Float,
     pub blue: Float,
 }
+
 impl Color {
     pub const fn new(red: Float, green: Float, blue: Float) -> Color {
         Color { red, green, blue }
     }
 }
+
+impl From<[Float; 3]> for Color {
+    fn from(rgb: [Float; 3]) -> Self {
+        Color {
+            red: rgb[0],
+            green: rgb[1],
+            blue: rgb[2],
+        }
+    }
+}
+
 impl PartialEq for Color {
     fn eq(&self, rhs: &Color) -> bool {
         ((self.red - rhs.red).abs() < EPSILON)
@@ -179,6 +181,7 @@ impl PartialEq for Color {
             && ((self.blue - rhs.blue).abs() < EPSILON)
     }
 }
+
 impl Add for Color {
     type Output = Self;
     fn add(self, other: Self) -> Self {
@@ -222,6 +225,7 @@ impl Mul<Color> for Float {
         }
     }
 }
+
 impl Mul<Color> for Color {
     type Output = Color;
     fn mul(self, rhs: Color) -> Self::Output {
@@ -243,6 +247,7 @@ impl Neg for Color {
         }
     }
 }
+
 impl Sub for Color {
     type Output = Self;
     fn sub(self, other: Self) -> Self {
@@ -256,7 +261,7 @@ impl Sub for Color {
 
 #[cfg(test)]
 mod tests {
-    use super::{cross, dot, Color, Float, Tuple, EPSILON};
+    use super::{cross, dot, reflect, Color, Float, Tuple, EPSILON};
     #[test]
     fn is_point() {
         // A tuple with w = 1 is a point
@@ -415,4 +420,20 @@ mod tests {
         let c2 = Color::new(0.9, 1., 0.1);
         assert_eq!(c1 * c2, Color::new(1.0 * 0.9, 0.2 * 1., 0.4 * 0.1));
     }
+    #[test]
+    fn reflect_approaching_at_45() {
+        // Reflecting a vector approaching at 45°
+        let v = Tuple::vector(1., -1., 0.);
+        let n = Tuple::vector(0., 1., 0.);
+        let r = reflect(v, n);
+        assert_eq!(r, Tuple::vector(1., 1., 0.));
+    }
+    #[test]
+    fn reflect_slanted_surface() {
+        // Reflecting off a slanted surface.
+        let v = Tuple::vector(0., -1., 0.);
+        let n = Tuple::vector((2. as Float).sqrt() / 2., (2. as Float).sqrt() / 2., 0.);
+        let r = reflect(v, n);
+        assert_eq!(r, Tuple::vector(1., 0., 0.));
+    }
 }

rtchallenge/src/world.rs

@@ -1,26 +1,19 @@
+use derive_builder::Builder;
+
 use crate::{
-    intersections::{prepare_computations, Intersections, PrecomputedData},
+    intersections::{prepare_computations, schlick, Intersections, PrecomputedData},
     lights::PointLight,
     materials::{lighting, Material},
     matrices::Matrix4x4,
     rays::Ray,
     shapes::{intersect, Shape},
-    tuples::{Color, Tuple},
+    tuples::{dot, Color, Tuple},
-    Float, BLACK, WHITE,
+    BLACK, WHITE,
 };
 
 /// World holds all drawable objects and the light(s) that illuminate them.
-///
+#[derive(Builder, Clone, Debug, Default)]
-/// # Examples
+#[builder(default)]
-/// ```
-/// use rtchallenge::world::World;
-///
-/// let w = World::default();
-/// assert!(w.objects.is_empty());
-/// assert_eq!(w.lights.len(), 0);
-/// ```
-
-#[derive(Clone, Debug, Default)]
 pub struct World {
     pub lights: Vec<PointLight>,
     pub objects: Vec<Shape>,
@@ -28,20 +21,11 @@ pub struct World {
 
 impl World {
     /// Creates a world suitable for use across multiple tests in from the book.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::world::World;
-    ///
-    /// let w = World::test_world();
-    /// assert_eq!(w.objects.len(), 2);
-    /// assert!(!w.lights.is_empty());
-    /// ```
     pub fn test_world() -> World {
         let light = PointLight::new(Tuple::point(-10., 10., -10.), WHITE);
         let mut s1 = Shape::sphere();
         s1.material = Material {
-            color: Color::new(0.8, 1., 0.6),
+            color: [0.8, 1., 0.6].into(),
             diffuse: 0.7,
             specular: 0.2,
             ..Material::default()
@@ -54,28 +38,9 @@ impl World {
         }
     }
 
-    /// Intesects the ray with this world.
+    /// Intersects the ray with this world.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{rays::Ray, tuples::Tuple, world::World};
-    ///
-    /// let w = World::test_world();
-    /// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-    /// let xs = w.intersect(&r);
-    /// assert_eq!(xs.len(), 4);
-    /// assert_eq!(xs[0].t, 4.);
-    /// assert_eq!(xs[1].t, 4.5);
-    /// assert_eq!(xs[2].t, 5.5);
-    /// assert_eq!(xs[3].t, 6.);
-    /// ```
     pub fn intersect(&self, r: &Ray) -> Intersections {
-        let mut xs: Vec<_> = self
+        let mut xs: Vec<_> = self.objects.iter().flat_map(|o| intersect(o, r)).collect();
-            .objects
-            .iter()
-            .map(|o| intersect(&o, &r))
-            .flatten()
-            .collect();
         xs.sort_by(|i1, i2| {
             i1.t.partial_cmp(&i2.t)
                 .expect("an intersection has a t value that is NaN")
@@ -84,147 +49,46 @@ impl World {
     }
 
     /// Compute shaded value for given precomputation.
-    ///
+    pub fn shade_hit(&self, comps: &PrecomputedData, remaining: usize) -> Color {
-    /// # Examples
+        let surface = self
-    /// ```
-    /// use rtchallenge::{
-    ///     intersections::{prepare_computations, Intersection},
-    ///     lights::PointLight,
-    ///     matrices::Matrix4x4,
-    ///     rays::Ray,
-    ///     shapes::Shape,
-    ///     tuples::{Color, Tuple},
-    ///     world::World,
-    ///     WHITE,
-    /// };
-    ///
-    /// // Shading an intersection.
-    /// let w = World::test_world();
-    /// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-    /// let s = &w.objects[0];
-    /// let i = Intersection::new(4., &s);
-    /// let comps = prepare_computations(&i, &r);
-    /// let c = w.shade_hit(&comps);
-    /// assert_eq!(c, Color::new(0.38066, 0.47583, 0.2855));
-    ///
-    /// // Shading an intersection from the inside.
-    /// let mut w = World::test_world();
-    /// w.lights = vec![PointLight::new(Tuple::point(0., 0.25, 0.), WHITE)];
-    /// let r = Ray::new(Tuple::point(0., 0., 0.), Tuple::vector(0., 0., 1.));
-    /// let s = &w.objects[1];
-    /// let i = Intersection::new(0.5, &s);
-    /// let comps = prepare_computations(&i, &r);
-    /// let c = w.shade_hit(&comps);
-    /// assert_eq!(c, Color::new(0.90498, 0.90498, 0.90498));
-    ///
-    /// // Shading with an intersection in shadow.
-    /// let mut w = World::default();
-    /// w.lights = vec![PointLight::new(Tuple::point(0., 0., -10.), WHITE)];
-    /// let s1 = Shape::sphere();
-    /// let mut s2 = Shape::sphere();
-    /// s2.set_transform(Matrix4x4::translation(0., 0., 10.));
-    /// w.objects = vec![s1, s2.clone()];
-    /// let r = Ray::new(Tuple::point(0., 0., 5.), Tuple::vector(0., 0., 1.));
-    /// let i = Intersection::new(4., &s2);
-    /// let comps = prepare_computations(&i, &r);
-    /// let c = w.shade_hit(&comps);
-    /// assert_eq!(c, Color::new(0.1, 0.1, 0.1));
-    /// ```
-    pub fn shade_hit(&self, comps: &PrecomputedData) -> Color {
-        let c = self
             .lights
             .iter()
             .fold(Color::new(0., 0., 0.), |acc, light| {
                 let shadowed = self.is_shadowed(comps.over_point, light);
-                acc + lighting(
+                let surface = lighting(
                     &comps.object.material,
+                    comps.object,
                     light,
                     comps.over_point,
                     comps.eyev,
                     comps.normalv,
                     shadowed,
-                )
+                );
+                acc + surface
             });
-        c / self.lights.len() as Float
+        let reflected = self.reflected_color(comps, remaining);
+        let refracted = self.refracted_color(comps, remaining);
+        let material = &comps.object.material;
+        if material.reflective > 0. && material.transparency > 0. {
+            let reflectance = schlick(comps);
+            surface + reflected * reflectance + refracted * (1. - reflectance)
+        } else {
+            surface + reflected + refracted
+        }
     }
     /// Compute color for given ray fired at the world.
-    ///
+    pub fn color_at(&self, r: &Ray, remaining: usize) -> Color {
-    /// # Examples
+        let xs = self.intersect(r);
-    /// ```
+        match xs.hit() {
-    /// use rtchallenge::{
-    ///     intersections::{prepare_computations, Intersection},
-    ///     lights::PointLight,
-    ///     rays::Ray,
-    ///     shapes::Shape,
-    ///     tuples::{Color, Tuple},
-    ///     world::World,
-    ///     BLACK,
-    /// };
-    ///
-    /// // The color when a ray misses.
-    /// let w = World::test_world();
-    /// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 1., 0.));
-    /// let c = w.color_at(&r);
-    /// assert_eq!(c, BLACK);
-    ///
-    /// // The color when a ray hits.
-    /// let w = World::test_world();
-    /// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
-    /// let c = w.color_at(&r);
-    /// assert_eq!(c, Color::new(0.38066, 0.47583, 0.2855));
-    ///
-    /// // The color with an intersection behind the ray.
-    /// let w = {
-    ///     let mut w = World::test_world();
-    ///     let mut outer = &mut w.objects[0];
-    ///     let m = outer.material.ambient = 1.;
-    ///     let inner = &mut w.objects[1];
-    ///     inner.material.ambient = 1.;
-    ///     w
-    /// };
-    /// let inner = &w.objects[1];
-    /// let r = Ray::new(Tuple::point(0., 0., 0.75), Tuple::vector(0., 0., -1.));
-    /// let c = w.color_at(&r);
-    /// assert_eq!(c, inner.material.color);
-    /// ```
-    pub fn color_at(&self, r: &Ray) -> Color {
-        match self.intersect(r).hit() {
             Some(hit) => {
-                let comps = prepare_computations(&hit, r);
+                let comps = prepare_computations(hit, r, &xs);
-                self.shade_hit(&comps)
+                self.shade_hit(&comps, remaining)
             }
             None => BLACK,
         }
     }
 
     /// Determine if point in world is in a shadow.
-    ///
-    /// # Examples
-    /// ```
-    /// use rtchallenge::{
-    ///     tuples::{ Tuple},
-    ///     shapes::Shape,
-    ///     world::World,
-    /// };
-    ///
-    /// let w = World::test_world();
-    /// let light = &w.lights[0];
-    ///
-    /// // There is no shadow when nothing is collinear with point and light.
-    /// let p = Tuple::point(0.,10.,0.);
-    /// assert_eq!(w.is_shadowed(p,light), false);
-    ///
-    /// // There shadow when an object is between the point and the light.
-    /// let p = Tuple::point(10.,-10.,10.);
-    /// assert_eq!(w.is_shadowed(p,light), true);
-    ///
-    /// // There is no shadow when an object is behind the light.
-    /// let p = Tuple::point(-20.,20.,-20.);
-    /// assert_eq!(w.is_shadowed(p,light), false);
-    ///
-    /// // There is no shadow when an object is behind the point.
-    /// let p = Tuple::point(-2.,2.,-2.);
-    /// assert_eq!(w.is_shadowed(p,light), false);
     pub fn is_shadowed(&self, point: Tuple, light: &PointLight) -> bool {
         let v = light.position - point;
         let distance = v.magnitude();
@@ -237,4 +101,455 @@ impl World {
         }
         false
     }
+
+    /// Compute reflected color for the given precomputation.
+    pub fn reflected_color(&self, comps: &PrecomputedData, remaining: usize) -> Color {
+        if remaining == 0 {
+            return BLACK;
+        }
+        if comps.object.material.reflective == 0. {
+            return BLACK;
+        }
+        // Fire reflected ray to figure out color.
+        let reflect_ray = Ray::new(comps.over_point, comps.reflectv);
+        let color = self.color_at(&reflect_ray, remaining - 1);
+        color * comps.object.material.reflective
+    }
+
+    /// Compute refracted color for the given precomputation.
+    pub fn refracted_color(&self, comps: &PrecomputedData, remaining: usize) -> Color {
+        if remaining == 0 {
+            return BLACK;
+        }
+        if comps.object.material.transparency == 0. {
+            return BLACK;
+        }
+        // Find the ratio of the first index of refraction to the secon
+        // (This is inverted from the definition of Snell's Law.)
+        let n_ratio = comps.n1 / comps.n2;
+
+        // cos(theta_i) is the same as the dot product of the two vectors
+        // TODO(wathiede): is cosine faster than doc productings?
+        let cos_i = dot(comps.eyev, comps.normalv);
+
+        // Find the sin(theta_t)^2 via trigonometric identity.
+        let sin2_t = n_ratio * n_ratio * (1. - cos_i * cos_i);
+
+        if sin2_t > 1. {
+            // Total internal reflection.
+            return BLACK;
+        }
+        // Find cos(theta_t) via trigonometric identity.
+        let cos_t = (1. - sin2_t).sqrt();
+        // Compute the direction of the refracted ray.
+        let direction = comps.normalv * (n_ratio * cos_i - cos_t) - comps.eyev * n_ratio;
+        // Create the refracted ray.
+        let refract_ray = Ray::new(comps.under_point, direction);
+        // Find he color of the refracted ray, making sure to multiply by the transparency value to
+        // account for any opacity.
+        self.color_at(&refract_ray, remaining - 1) * comps.object.material.transparency
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        float::consts::SQRT_2,
+        intersections::{prepare_computations, Intersection, Intersections},
+        lights::PointLight,
+        materials::MaterialBuilder,
+        matrices::translation,
+        patterns::test_pattern,
+        rays::Ray,
+        shapes::{plane, sphere, Shape, ShapeBuilder},
+        tuples::{point, vector},
+        world::{World, WorldBuilder},
+        Float, BLACK, WHITE,
+    };
+
+    mod intersect {
+        use super::*;
+
+        #[test]
+        fn intersection_with_test_world() {
+            let w = World::test_world();
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let xs = w.intersect(&r);
+            assert_eq!(xs.len(), 4);
+            assert_eq!(xs[0].t, 4.);
+            assert_eq!(xs[1].t, 4.5);
+            assert_eq!(xs[2].t, 5.5);
+            assert_eq!(xs[3].t, 6.);
+        }
+    }
+    mod world {
+        use super::*;
+
+        #[test]
+        fn default_world() {
+            let w = World::default();
+            assert!(w.objects.is_empty());
+            assert_eq!(w.lights.len(), 0);
+        }
+        #[test]
+        fn test_world() {
+            let w = World::test_world();
+            assert_eq!(w.objects.len(), 2);
+            assert!(!w.lights.is_empty());
+        }
+    }
+    mod shade_hit {
+        use super::*;
+
+        #[test]
+        fn shading_an_intersection() {
+            // Shading an intersection.
+            let w = World::test_world();
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let s = &w.objects[0];
+            let xs = Intersections::from(Intersection::new(4., &s));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.shade_hit(&comps, 1);
+            assert_eq!(c, [0.38066, 0.47583, 0.2855].into());
+        }
+        #[test]
+        fn shading_an_intersection_from_inside() {
+            // Shading an intersection from the inside.
+            let mut w = World::test_world();
+            w.lights = vec![PointLight::new(point(0., 0.25, 0.), WHITE)];
+            let r = Ray::new(point(0., 0., 0.), vector(0., 0., 1.));
+            let s = &w.objects[1];
+            let xs = Intersections::from(Intersection::new(0.5, &s));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.shade_hit(&comps, 1);
+            assert_eq!(c, [0.90498, 0.90498, 0.90498].into());
+        }
+        #[test]
+        fn shading_an_intersection_in_shadow() {
+            // Shading with an intersection in shadow.
+            let mut w = World::default();
+            w.lights = vec![PointLight::new(point(0., 0., -10.), WHITE)];
+            let s1 = Shape::sphere();
+            let mut s2 = Shape::sphere();
+            s2.set_transform(translation(0., 0., 10.));
+            w.objects = vec![s1, s2.clone()];
+            let r = Ray::new(point(0., 0., 5.), vector(0., 0., 1.));
+            let xs = Intersections::from(Intersection::new(4., &s2));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.shade_hit(&comps, 1);
+            assert_eq!(c, [0.1, 0.1, 0.1].into());
+        }
+        #[test]
+        fn shading_with_a_reflective_material() -> Result<(), Box<dyn std::error::Error>> {
+            // Shading with a reflective material.
+            let mut w = World::test_world();
+            let shape = ShapeBuilder::plane()
+                .material(MaterialBuilder::default().reflective(0.5).build()?)
+                .transform(translation(0., -1., 0.))
+                .build()?;
+            w.objects.push(shape.clone());
+            let r = Ray::new(
+                point(0., 0., -3.),
+                vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
+            );
+            let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.shade_hit(&comps, 1);
+            assert_eq!(c, [0.87676, 0.92434, 0.82917].into());
+            Ok(())
+        }
+        #[test]
+        fn shading_with_a_transparent_material() -> Result<(), Box<dyn std::error::Error>> {
+            // shade_hit() with a transparent material.
+            let mut w = World::test_world();
+            let floor = plane()
+                .transform(translation(0., -1., 0.))
+                .material(
+                    MaterialBuilder::default()
+                        .transparency(0.5)
+                        .refractive_index(1.5)
+                        .build()?,
+                )
+                .build()?;
+            w.objects.push(floor.clone());
+            let ball = sphere()
+                .material(
+                    MaterialBuilder::default()
+                        .color([1., 0., 0.])
+                        .ambient(0.5)
+                        .build()?,
+                )
+                .transform(translation(0., -3.5, -0.5))
+                .build()?;
+            w.objects.push(ball);
+            let r = Ray::new(
+                point(0., 0., -3.),
+                vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
+            );
+            let xs = Intersections::new(vec![Intersection::new((2 as Float).sqrt(), &floor)]);
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.shade_hit(&comps, 5);
+            assert_eq!(c, [0.93642, 0.68642, 0.68643].into());
+            Ok(())
+        }
+        #[test]
+        fn reflective_transparent_material() -> Result<(), Box<dyn std::error::Error>> {
+            let mut w = World::test_world();
+            let floor = plane()
+                .transform(translation(0., -1., 0.))
+                .material(
+                    MaterialBuilder::default()
+                        .reflective(0.5)
+                        .transparency(0.5)
+                        .refractive_index(1.5)
+                        .build()?,
+                )
+                .build()?;
+            w.objects.push(floor.clone());
+            let ball = sphere()
+                .transform(translation(0., -3.5, -0.5))
+                .material(
+                    MaterialBuilder::default()
+                        .color([1., 0., 0.])
+                        .ambient(0.5)
+                        .build()?,
+                )
+                .build()?;
+            w.objects.push(ball);
+            let r = Ray::new(point(0., 0., -3.), vector(0., -SQRT_2 / 2., SQRT_2 / 2.));
+            let xs = Intersections::new(vec![Intersection::new(SQRT_2, &floor)]);
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let color = w.shade_hit(&comps, 5);
+            assert_eq!(color, [0.93391, 0.69643, 0.69243].into());
+            Ok(())
+        }
+    }
+    mod color_at {
+        use super::*;
+
+        #[test]
+        fn color_when_ray_misses() {
+            // The color when a ray misses.
+            let w = World::test_world();
+            let r = Ray::new(point(0., 0., -5.), vector(0., 1., 0.));
+            let c = w.color_at(&r, 1);
+            assert_eq!(c, BLACK);
+        }
+        #[test]
+        fn color_when_ray_hits() {
+            // The color when a ray hits.
+            let w = World::test_world();
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let c = w.color_at(&r, 1);
+            assert_eq!(c, [0.38066, 0.47583, 0.2855].into());
+        }
+        #[test]
+        fn color_with_an_intersection_behind_ray() {
+            // The color with an intersection behind the ray.
+            let w = {
+                let mut w = World::test_world();
+                let mut outer = &mut w.objects[0];
+                outer.material.ambient = 1.;
+                let inner = &mut w.objects[1];
+                inner.material.ambient = 1.;
+                w
+            };
+            let r = Ray::new(point(0., 0., 0.75), vector(0., 0., -1.));
+            let c = w.color_at(&r, 1);
+            // inner.material.color is WHITE
+            assert_eq!(c, WHITE);
+        }
+        #[test]
+        fn ensure_mutually_reflective_surfaces_terminate() -> Result<(), Box<dyn std::error::Error>>
+        {
+            // Ensure mutually reflective surfaces don't infinitely recurse.
+            let lower = ShapeBuilder::plane()
+                .material(MaterialBuilder::default().reflective(1.).build()?)
+                .transform(translation(0., -1., 0.))
+                .build()?;
+            let upper = ShapeBuilder::plane()
+                .material(MaterialBuilder::default().reflective(1.).build()?)
+                .transform(translation(0., 1., 0.))
+                .build()?;
+            let w = WorldBuilder::default()
+                .lights(vec![PointLight::new(point(0., 0., 0.), WHITE)])
+                .objects(vec![lower, upper])
+                .build()?;
+            let r = Ray::new(point(0., 0., 0.), vector(0., 1., 0.));
+            // This should complete without stack overflow.
+            w.color_at(&r, 1);
+            Ok(())
+        }
+    }
+    mod is_shadowed {
+        use super::*;
+
+        #[test]
+        fn no_shadow_when_nothing_collinear_with_point_and_light() {
+            // There is no shadow when nothing is collinear with point and light.
+            let w = World::test_world();
+            let light = &w.lights[0];
+
+            let p = point(0., 10., 0.);
+            assert_eq!(w.is_shadowed(p, light), false);
+        }
+        #[test]
+        fn shadow_when_object_between_point_and_light() {
+            // The shadow when an object is between the point and the light.
+            let w = World::test_world();
+            let light = &w.lights[0];
+
+            let p = point(10., -10., 10.);
+            assert_eq!(w.is_shadowed(p, light), true);
+        }
+
+        #[test]
+        fn no_shadow_when_object_behind_light() {
+            // There is no shadow when an object is behind the light.
+            let w = World::test_world();
+            let light = &w.lights[0];
+
+            let p = point(-20., 20., -20.);
+            assert_eq!(w.is_shadowed(p, light), false);
+        }
+        #[test]
+        fn no_shadow_when_object_behind_point() {
+            // There is no shadow when an object is behind the point.
+            let w = World::test_world();
+            let light = &w.lights[0];
+
+            let p = point(-2., 2., -2.);
+            assert_eq!(w.is_shadowed(p, light), false);
+        }
+    }
+
+    mod reflected_color {
+        use super::*;
+
+        #[test]
+        fn reflected_color_for_nonreflective_material() {
+            // The reflected color for a nonreflective material.
+            let r = Ray::new(point(0., 0., 0.), vector(0., 0., 1.));
+            let mut w = World::test_world();
+            w.objects[1].material.ambient = 1.;
+            let xs = Intersections::from(Intersection::new(1., &w.objects[1]));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.reflected_color(&comps, 1);
+            assert_eq!(c, BLACK);
+        }
+        #[test]
+        fn reflected_color_for_reflective_material() -> Result<(), Box<dyn std::error::Error>> {
+            // The reflected color for a reflective material.
+            let mut w = World::test_world();
+            let shape = ShapeBuilder::plane()
+                .material(MaterialBuilder::default().reflective(0.5).build()?)
+                .transform(translation(0., -1., 0.))
+                .build()?;
+            w.objects.push(shape.clone());
+            let r = Ray::new(
+                point(0., 0., -3.),
+                vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
+            );
+            let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.reflected_color(&comps, 1);
+            assert_eq!(c, [0.19033, 0.23791, 0.14274].into());
+            Ok(())
+        }
+        #[test]
+        fn reflected_color_at_maximum_recursion_depth() -> Result<(), Box<dyn std::error::Error>> {
+            // The reflected color at the maximum recursion depth.
+            let mut w = World::test_world();
+            let shape = ShapeBuilder::plane()
+                .material(MaterialBuilder::default().reflective(0.5).build()?)
+                .transform(translation(0., -1., 0.))
+                .build()?;
+            w.objects.push(shape.clone());
+            let r = Ray::new(
+                point(0., 0., -3.),
+                vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
+            );
+            let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let _ = w.reflected_color(&comps, 0);
+            // Just needs to get here without infinite recursion.
+
+            Ok(())
+        }
+    }
+    mod refracted_color {
+        use super::*;
+
+        #[test]
+        fn refracted_color_with_opaque_surface() {
+            // The refracted color with an opaque surface.
+            let w = World::test_world();
+            let shape = &w.objects[0];
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let xs = Intersections::new(vec![
+                Intersection::new(4., &shape),
+                Intersection::new(6., &shape),
+            ]);
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.refracted_color(&comps, 5);
+            assert_eq!(c, BLACK);
+        }
+        #[test]
+        fn refracted_color_at_maximum_recursion_depth() {
+            // The refracted color at the maximum recursive depth.
+            let mut w = World::test_world();
+            w.objects[0].material.transparency = 1.0;
+            w.objects[0].material.refractive_index = 1.5;
+            let shape = &w.objects[0];
+            let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
+            let xs = Intersections::new(vec![
+                Intersection::new(4., &shape),
+                Intersection::new(6., &shape),
+            ]);
+            let comps = prepare_computations(&xs[0], &r, &xs);
+            let c = w.refracted_color(&comps, 0);
+            assert_eq!(c, BLACK);
+        }
+        #[test]
+        fn refracted_color_under_total_internal_reflection() {
+            // The refracted color under total internal reflection.
+            let mut w = World::test_world();
+            w.objects[0].material.transparency = 1.0;
+            w.objects[0].material.refractive_index = 1.5;
+            let shape = &w.objects[0];
+            let r = Ray::new(point(0., 0., (2 as Float).sqrt() / 2.), vector(0., 1., 0.));
+            let xs = Intersections::new(vec![
+                Intersection::new(-(2 as Float).sqrt() / 2., &shape),
+                Intersection::new((2 as Float).sqrt() / 2., &shape),
+            ]);
+            let comps = prepare_computations(&xs[1], &r, &xs);
+            let c = w.refracted_color(&comps, 5);
+            assert_eq!(c, BLACK);
+        }
+        #[test]
+        fn refracted_color_with_a_refracted_ray() -> Result<(), Box<dyn std::error::Error>> {
+            // The refracted color with a refracted ray.
+            let mut w = World::test_world();
+            w.objects[0].material.ambient = 1.;
+            w.objects[0].material.color = test_pattern().build()?;
+
+            w.objects[1].material.transparency = 1.;
+            w.objects[1].material.refractive_index = 1.5;
+
+            let r = Ray::new(point(0., 0., 0.1), vector(0., 1., 0.));
+            let a = &w.objects[0];
+            let b = &w.objects[1];
+            let xs = Intersections::new(vec![
+                Intersection::new(-0.9899, &a),
+                Intersection::new(-0.4899, &b),
+                Intersection::new(0.4899, &b),
+                Intersection::new(0.9899, &a),
+            ]);
+            let comps = prepare_computations(&xs[2], &r, &xs);
+            let c = w.refracted_color(&comps, 5);
+            assert_eq!(c, [0., 0.99887, 0.04721].into());
+
+            Ok(())
+        }
+    }
 }

rtiow/Cargo.toml

@@ -1,13 +1,15 @@
 [workspace]
+resolver = "2"
 
 members = [
   "noise_explorer",
   "noise_explorer_warp",
   "renderer",
   "tracer",
+  "vec3",
 ]
-
-[profile]
 [profile.release]
 debug = true
 
+[profile.dev]
+opt-level = 3 

rtiow/noise_explorer/Cargo.toml

@@ -2,19 +2,19 @@
 name = "noise_explorer"
 version = "0.1.0"
 authors = ["Bill Thiede <git@xinu.tv>"]
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-actix-web = "0.7.8"
+actix-web = "0.7.19"
-askama = "0.7.1"
+askama = "0.7.2"
-image = "0.22.3"
+image = "0.22.5"
-log = "0.4.5"
+log = "0.4.17"
-rand = "0.8.3"
+rand = "0.8.5"
 rand_xorshift = "0.3.0"
 renderer = { path = "../renderer" }
-serde = "1.0.79"
+serde = "1.0.152"
-serde_derive = "1.0.79"
+serde_derive = "1.0.152"
-stderrlog = "0.4.1"
+stderrlog = "0.4.3"
-structopt = "0.2.10"
+structopt = "0.2.18"

rtiow/noise_explorer/rustfmt.toml

@@ -1 +1,2 @@
+imports_granularity = "Crate"
 format_code_in_doc_comments = true

rtiow/noise_explorer/src/main.rs

@@ -1,44 +1,26 @@
-use std::fmt;
+use std::{fmt, time::SystemTime};
-use std::time::SystemTime;
 
-use actix_web::http;
+use actix_web::{http, middleware, server, App, HttpRequest, HttpResponse, Path, Query, Result};
-use actix_web::middleware;
-use actix_web::server;
-use actix_web::App;
-use actix_web::HttpRequest;
-use actix_web::HttpResponse;
-use actix_web::Path;
-use actix_web::Query;
-use actix_web::Result;
 use askama::Template;
-use image;
 use log::info;
 use rand::SeedableRng;
 use rand_xorshift::XorShiftRng;
 use serde_derive::Deserialize;
 use structopt::StructOpt;
 
-use renderer::noise;
+use renderer::{
-use renderer::noise::lode::Lode;
+    noise,
-use renderer::noise::perlin::Perlin;
+    noise::{lode::Lode, perlin::Perlin, NoiseType},
-use renderer::noise::NoiseType;
+    texture::{NoiseTexture, Texture},
-use renderer::texture::NoiseTexture;
+    vec3::Vec3,
-use renderer::texture::Texture;
+};
-use renderer::vec3::Vec3;
 
-#[derive(Debug, StructOpt)]
+#[derive(StructOpt)]
 #[structopt(name = "noise_explorer", about = "CLI for exploring Perlin noise")]
 struct Opt {
     /// HTTP listen address
     #[structopt(long = "addr", default_value = "0.0.0.0:8889")]
     pub addr: String,
-
-    /// Width of noise images
-    #[structopt(short = "w", long = "width", default_value = "128")]
-    pub width: u32,
-    /// Height of noise images
-    #[structopt(short = "h", long = "height", default_value = "128")]
-    pub height: u32,
 }
 
 #[derive(Copy, Clone, Debug, Deserialize, PartialEq)]
@@ -63,11 +45,6 @@ struct OptionalParams {
     pixel_scale: f32,
 }
 
-#[derive(Debug, Deserialize)]
-struct NoiseSourceParam {
-    noise_source: NoiseSource,
-}
-
 #[derive(Debug, Deserialize)]
 struct NoiseParams {
     width: u32,
@@ -466,16 +443,9 @@ fn main() -> Result<(), std::io::Error> {
 mod tests {
     use std::str;
 
-    use actix_web::http::Method;
+    use actix_web::{http::Method, test::TestServer, HttpMessage, Path, Query};
-    use actix_web::test::TestServer;
-    use actix_web::HttpMessage;
-    use actix_web::Path;
-    use actix_web::Query;
 
-    use super::NoiseParamsMarble;
+    use super::{NoiseParamsMarble, NoiseParamsScale, NoiseParamsTurbulence, OptionalParams};
-    use super::NoiseParamsScale;
-    use super::NoiseParamsTurbulence;
-    use super::OptionalParams;
 
     #[test]
     fn noise_param_from_req() {

rtiow/noise_explorer_warp/Cargo.toml

@@ -2,18 +2,18 @@
 name = "noise_explorer_warp"
 version = "0.1.0"
 authors = ["Bill Thiede <git@xinu.tv>"]
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-askama = "0.7.1"
+askama = "0.7.2"
-image = "0.22.3"
+image = "0.22.5"
-log = "0.4.5"
+log = "0.4.17"
-rand = "0.5.5"
+rand = "0.5.6"
 renderer = { path = "../renderer" }
-serde = "1.0.79"
+serde = "1.0.152"
-serde_derive = "1.0.79"
+serde_derive = "1.0.152"
-stderrlog = "0.4.1"
+stderrlog = "0.4.3"
-structopt = "0.2.10"
+structopt = "0.2.18"
-warp = "0.1.20"
+warp = "0.1.23"

rtiow/noise_explorer_warp/rustfmt.toml

@@ -0,0 +1,2 @@
+imports_granularity = "Crate"
+format_code_in_doc_comments = true

rtiow/renderer/Cargo.toml

@@ -2,29 +2,41 @@
 name = "renderer"
 version = "0.1.0"
 authors = ["Bill Thiede <git@xinu.tv>"]
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [[bench]]
 harness = false
 name = "spheres"
+[[bench]]
+harness = false
+name = "aabb"
 
 [dependencies]
 chrono = "*"
 core_affinity = "0.5"
 cpuprofiler = { version = "0.0.3", optional = true }
-image = "0.22.3"
+image = "0.22.5"
-lazy_static = "1.1.0"
+lazy_static = "1.4.0"
-log = "0.4.5"
+log = "0.4.17"
-num_cpus = "1.8.0"
+num_cpus = "1.15.0"
-rand = "0.8.3"
+rand = "0.8.5"
-serde = "1.0.79"
+serde = "1.0.152"
-serde_derive = "1.0.79"
+serde_derive = "1.0.152"
-serde_json = "1.0.41"
+serde_json = "1.0.93"
-structopt = "0.2.10"
+structopt = "0.2.18"
+vec3 = {path = "../vec3"}
+stl = {path = "../../../stl"}
+strum = { version = "0.24.1", features = ["derive"] }
+strum_macros = "0.24.3"
+thiserror = "1.0.38"
+tev_client = "0.5.2"
+#stl = {git = "https://git-private.z.xinu.tv/wathiede/stl"}
 
 [dev-dependencies]
-criterion = "0.2"
+criterion = "0.4"
+pretty_assertions = "1.3.0"
+proptest = "1.1.0"
 
 [features]
 profile = ["cpuprofiler"]

rtiow/renderer/benches/aabb.rs

@@ -0,0 +1,47 @@
+use criterion::*;
+use renderer::{aabb::AABB, ray::Ray};
+
+fn bench(c: &mut Criterion) {
+    let bb = AABB::new([1., -1., -1.], [3., 1., 1.]);
+    let r_hit = Ray::new([0., 0., 0.], [1., 0., 0.], 0.);
+    let r_miss = Ray::new([0., 0., 0.], [-1., 0., 0.], 0.);
+    let t_min = 0.001;
+    let t_max = f32::MAX;
+
+    let mut group = c.benchmark_group("aabb");
+    group.throughput(Throughput::Elements(1));
+    group.bench_with_input(BenchmarkId::new("hit_naive", "r_hit"), &r_hit, |b, r| {
+        b.iter(|| bb.hit_naive(*r, t_min, t_max))
+    });
+    group.bench_with_input(BenchmarkId::new("hit2", "r_hit"), &r_hit, |b, r| {
+        b.iter(|| bb.hit2(*r, t_min, t_max))
+    });
+    //group.bench_with_input(BenchmarkId::new("hit_precompute", "r_hit"), &r_hit, |b, r| { b.iter(|| bb.hit_precompute(*r, t_min, t_max)) });
+    group.bench_with_input(BenchmarkId::new("hit_fast", "r_hit"), &r_hit, |b, r| {
+        b.iter(|| bb.hit_fast(*r, t_min, t_max))
+    });
+    #[cfg(target_arch = "x86_64")]
+    group.bench_with_input(BenchmarkId::new("hit_simd", "r_hit"), &r_hit, |b, r| {
+        b.iter(|| bb.hit_simd(*r, t_min, t_max))
+    });
+
+    group.bench_with_input(BenchmarkId::new("hit_naive", "r_miss"), &r_miss, |b, r| {
+        b.iter(|| bb.hit_naive(*r, t_min, t_max))
+    });
+    group.bench_with_input(BenchmarkId::new("hit2", "r_miss"), &r_miss, |b, r| {
+        b.iter(|| bb.hit2(*r, t_min, t_max))
+    });
+    //group.bench_with_input(BenchmarkId::new("hit_precompute", "r_miss"), &r_miss, |b, r| { b.iter(|| bb.hit_precompute(*r, t_min, t_max)) });
+    group.bench_with_input(BenchmarkId::new("hit_fast", "r_miss"), &r_miss, |b, r| {
+        b.iter(|| bb.hit_fast(*r, t_min, t_max))
+    });
+    #[cfg(target_arch = "x86_64")]
+    group.bench_with_input(BenchmarkId::new("hit_simd", "r_miss"), &r_miss, |b, r| {
+        b.iter(|| bb.hit_simd(*r, t_min, t_max))
+    });
+
+    group.finish();
+}
+
+criterion_group!(benches, bench);
+criterion_main!(benches);

rtiow/renderer/benches/spheres.rs

@@ -1,15 +1,9 @@
-#[macro_use]
+use criterion::*;
-extern crate criterion;
 
-use criterion::Criterion;
+use renderer::{
-use criterion::ParameterizedBenchmark;
+    hitable::Hit, material::Lambertian, ray::Ray, sphere::Sphere, texture::ConstantTexture,
-
+    vec3::Vec3,
-use rtiow::hitable::Hit;
+};
-use rtiow::material::Lambertian;
-use rtiow::ray::Ray;
-use rtiow::sphere::Sphere;
-use rtiow::texture::ConstantTexture;
-use rtiow::vec3::Vec3;
 
 fn criterion_benchmark(c: &mut Criterion) {
     let sphere = Sphere::new(
@@ -23,14 +17,15 @@ fn criterion_benchmark(c: &mut Criterion) {
         // Miss
         Ray::new([0., 0., -2.], [0., 0., -1.], 0.),
     ];
-    c.bench(
+    let mut group = c.benchmark_group("sphere");
-        "sphere",
+    group.throughput(Throughput::Elements(1));
-        ParameterizedBenchmark::new(
+    group.bench_with_input(BenchmarkId::new("Sphere", "hit"), &rays[0], |b, r| {
-            "Sphere",
+        b.iter(|| sphere.hit(*r, 0., 1.))
-            move |b, r| b.iter(|| sphere.hit(*r, 0., 1.)),
+    });
-            rays,
+    group.bench_with_input(BenchmarkId::new("Sphere", "miss"), &rays[1], |b, r| {
-        ),
+        b.iter(|| sphere.hit(*r, 0., 1.))
-    );
+    });
+    group.finish()
 }
 
 criterion_group!(benches, criterion_benchmark);

rtiow/renderer/rustfmt.toml

@@ -0,0 +1,2 @@
+imports_granularity = "Crate"
+format_code_in_doc_comments = true

rtiow/renderer/src/aabb.rs

@@ -1,9 +1,8 @@
 use std::fmt;
 
-use crate::ray::Ray;
+use crate::{ray::Ray, vec3::Vec3};
-use crate::vec3::Vec3;
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Default, Copy, Clone, PartialEq)]
 pub struct AABB {
     bounds: [Vec3; 2],
 }
@@ -30,15 +29,65 @@ fn max(x: f32, y: f32) -> f32 {
     }
 }
 
+impl fmt::Debug for AABB {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "AABB: <{} - {}> Vol: {} Area: {}",
+            self.bounds[0],
+            self.bounds[1],
+            self.volume(),
+            self.area()
+        )
+    }
+}
+
 impl AABB {
-    pub fn new(min: Vec3, max: Vec3) -> AABB {
+    // Create AABB with min = f32::MAX and max = -f32::MAX. It is expected the caller will use grow to create
+    // a vaild AABB.
+    pub fn infinite() -> AABB {
+        AABB {
+            bounds: [Vec3::from(f32::MAX), Vec3::from(f32::MIN)],
+        }
+    }
+    pub fn new<V: Into<Vec3>>(min: V, max: V) -> AABB {
+        let min: Vec3 = min.into();
+        let max: Vec3 = max.into();
+        assert!(min.x <= max.x);
+        assert!(min.y <= max.y);
+        assert!(min.z <= max.z);
         AABB { bounds: [min, max] }
     }
 
+    pub fn area(&self) -> f32 {
+        if self.max().x == f32::MIN || self.min().x == f32::MAX {
+            return 0.;
+        }
+        let e = self.max() - self.min();
+        let v = e.x * e.y + e.y * e.z + e.z * e.x;
+        if v.is_finite() {
+            v
+        } else {
+            0.
+        }
+    }
     pub fn volume(&self) -> f32 {
-        (self.min().x - self.max().x).abs()
+        if self.max().x == f32::MIN || self.min().x == f32::MAX {
+            return 0.;
+        }
+        let v = (self.min().x - self.max().x).abs()
             * (self.min().y - self.max().y).abs()
-            * (self.min().z - self.max().z).abs()
+            * (self.min().z - self.max().z).abs();
+        if v.is_finite() {
+            v
+        } else {
+            0.
+        }
+    }
+
+    pub fn grow(&mut self, v: Vec3) {
+        self.bounds[0] = vec3::min(self.bounds[0], v);
+        self.bounds[1] = vec3::max(self.bounds[1], v);
     }
 
     pub fn longest_axis(&self) -> usize {
@@ -62,11 +111,39 @@ impl AABB {
     pub fn min(&self) -> Vec3 {
         self.bounds[0]
     }
+
     pub fn max(&self) -> Vec3 {
         self.bounds[1]
     }
 
-    pub fn hit2(&self, r: Ray, t_min: f32, t_max: f32) -> bool {
+    // TODO(wathiede): implement branchless https://tavianator.com/cgit/dimension.git/tree/libdimension/bvh/bvh.c#n194
+
+    pub fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> bool {
+        self.hit_simd(r, t_min, t_max).is_some()
+    }
+
+    pub fn hit_distance(&self, r: Ray, t_min: f32, t_max: f32) -> Option<f32> {
+        self.hit_simd(r, t_min, t_max)
+    }
+
+    pub fn hit_naive(&self, r: Ray, t_min: f32, t_max: f32) -> Option<f32> {
+        let mut t_min = t_min;
+        let mut t_max = t_max;
+        for axis in 0..3 {
+            let t0 = ((self.min()[axis] - r.origin[axis]) * r.inv_direction[axis])
+                .min((self.max()[axis] - r.origin[axis]) * r.inv_direction[axis]);
+            let t1 = ((self.min()[axis] - r.origin[axis]) * r.inv_direction[axis])
+                .max((self.max()[axis] - r.origin[axis]) * r.inv_direction[axis]);
+            t_min = t0.max(t_min);
+            t_max = t1.min(t_max);
+            if t_max <= t_min {
+                return None;
+            }
+        }
+        Some(t_min)
+    }
+
+    pub fn hit2(&self, r: Ray, t_min: f32, t_max: f32) -> Option<f32> {
         let mut t_min = t_min;
         let mut t_max = t_max;
         for axis in 0..3 {
@@ -82,13 +159,13 @@ impl AABB {
             t_min = max(t0, t_min);
             t_max = min(t1, t_max);
             if t_max <= t_min {
-                return false;
+                return None;
             }
         }
-        true
+        Some(t_min)
     }
 
-    pub fn hit_precompute(&self, r: Ray, t0: f32, t1: f32) -> bool {
+    pub fn hit_precompute(&self, r: Ray, t0: f32, t1: f32) -> Option<f32> {
         // TODO(wathiede): this has bugs.
         let mut t_min = (self.bounds[r.sign[0]].x - r.origin.x) * r.inv_direction.x;
         let mut t_max = (self.bounds[1 - r.sign[0]].x - r.origin.x) * r.inv_direction.x;
@@ -96,7 +173,7 @@ impl AABB {
         let t_y_max = (self.bounds[1 - r.sign[0]].y - r.origin.y) * r.inv_direction.y;
 
         if t_min > t_y_max || t_y_min > t_max {
-            return false;
+            return None;
         }
 
         if t_y_min > t_min {
@@ -109,7 +186,7 @@ impl AABB {
         let t_z_min = (self.bounds[r.sign[2]].z - r.origin.z) * r.inv_direction.z;
         let t_z_max = (self.bounds[1 - r.sign[2]].z - r.origin.z) * r.inv_direction.z;
         if t_min > t_z_max || t_z_min > t_max {
-            return false;
+            return None;
         }
         if t_z_min > t_min {
             t_min = t_z_min;
@@ -117,27 +194,42 @@ impl AABB {
         if t_z_max < t_max {
             t_max = t_z_max;
         }
-        t_min < t1 && t_max > t0
+        if t_min < t1 && t_max > t0 {
+            Some(t_min)
+        } else {
+            None
+        }
     }
 
-    pub fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> bool {
+    pub fn hit_simd(&self, r: Ray, t_min: f32, t_max: f32) -> Option<f32> {
-        let mut t_min = t_min;
+        #[cfg(target_arch = "x86_64")]
-        let mut t_max = t_max;
+        unsafe {
-        for axis in 0..3 {
+            use std::arch::x86_64::*;
-            let t0 = ((self.min()[axis] - r.origin[axis]) * r.inv_direction[axis])
+            let o4 = _mm_set_ps(0., r.origin.z, r.origin.y, r.origin.x);
-                .min((self.max()[axis] - r.origin[axis]) * r.inv_direction[axis]);
+            let d4 = _mm_set_ps(0., r.inv_direction.z, r.inv_direction.y, r.inv_direction.x);
-            let t1 = ((self.min()[axis] - r.origin[axis]) * r.inv_direction[axis])
+            let bmin4 = _mm_set_ps(0., self.min().z, self.min().y, self.min().x);
-                .max((self.max()[axis] - r.origin[axis]) * r.inv_direction[axis]);
+            let bmax4 = _mm_set_ps(0., self.max().z, self.max().y, self.max().x);
-            t_min = t0.max(t_min);
+            let mask4 = _mm_cmpeq_ps(_mm_setzero_ps(), _mm_set_ps(1., 0., 0., 0.));
-            t_max = t1.min(t_max);
+            let t1 = _mm_mul_ps(_mm_sub_ps(_mm_and_ps(bmin4, mask4), o4), d4);
-            if t_max <= t_min {
+            let t2 = _mm_mul_ps(_mm_sub_ps(_mm_and_ps(bmax4, mask4), o4), d4);
-                return false;
+            let vmax4 = _mm_max_ps(t1, t2);
+            let vmin4 = _mm_min_ps(t1, t2);
+            let vmax4: (f32, f32, f32, f32) = std::mem::transmute(vmax4);
+            let vmin4: (f32, f32, f32, f32) = std::mem::transmute(vmin4);
+            let tmax = min(min(vmax4.0, min(vmax4.1, vmax4.2)), t_max);
+            let tmin = max(max(vmin4.0, max(vmin4.1, vmin4.2)), t_min);
+            if tmin <= tmax {
+                Some(tmin)
+            } else {
+                None
             }
         }
-        true
+        #[cfg(target_arch = "aarch64")]
+        // TODO(wathiede): add NEON implementation.
+        self.hit2(r, t_min, t_max)
     }
 
-    pub fn hit_fast(&self, r: Ray, _t_min: f32, _t_max: f32) -> bool {
+    pub fn hit_fast(&self, r: Ray, _t_min: f32, _t_max: f32) -> Option<f32> {
         let b = self;
         let mut t1 = (b.min()[0] - r.origin[0]) * 1. / r.direction[0];
         let mut t2 = (b.max()[0] - r.origin[0]) * 1. / r.direction[0];
@@ -153,7 +245,11 @@ impl AABB {
             tmax = tmax.min(t1.max(t2));
         }
 
-        tmax > tmin.max(0.0)
+        if tmax > tmin.max(0.0) {
+            Some(tmin)
+        } else {
+            None
+        }
     }
 }
 
@@ -170,3 +266,112 @@ pub fn surrounding_box(box0: &AABB, box1: &AABB) -> AABB {
     );
     AABB::new(min, max)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn infinite() {
+        let bb = AABB::infinite();
+        assert_eq!(bb.area(), 0.);
+        assert_eq!(bb.volume(), 0.);
+    }
+
+    macro_rules! hit_test {
+        ($($name:ident,)*) => {
+            $(
+                mod $name {
+                    use super::*;
+                    const T_MIN: f32 = 0.001;
+                    const T_MAX: f32 = f32::MAX;
+
+                    fn test_bb() -> AABB {
+                        AABB::new([-1., -1., -1.], [1., 1., 1.])
+                    }
+
+                    #[test]
+                    fn hit_front() {
+                        let bb = test_bb();
+                        let r = Ray::new([-2., 0., 0.], [1., 0., 0.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+                    #[test]
+                    fn hit_back() {
+                        let bb = test_bb();
+                        let r = Ray::new([2., 0., 0.], [-1., 0., 0.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+                    #[test]
+                    fn hit_top() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 2., 0.], [0., -1., 0.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+                    #[test]
+                    fn hit_bottom() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., -2., 0.], [0., 1., 0.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+                    #[test]
+                    fn hit_left() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 0., -2.], [0., 0., 1.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+                    #[test]
+                    fn hit_right() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 0., 2.], [0., 0., -1.], 0.5);
+                        assert!(bb.$name(r, T_MIN, T_MAX).is_some());
+                    }
+
+                    #[test]
+                    fn miss_front() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 1.1, -1.1], [0., -1., 0.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                    #[test]
+                    fn miss_back() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 1.1, 1.1], [0., -1., 0.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                    #[test]
+                    fn miss_top() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., 1.1, -1.1], [0., 0., 1.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                    #[test]
+                    fn miss_bottom() {
+                        let bb = test_bb();
+                        let r = Ray::new([0., -1.1, -1.1], [0., 0., 1.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                    #[test]
+                    fn miss_left() {
+                        let bb = test_bb();
+                        let r = Ray::new([-1.1, 0., -1.1], [0., 0., 1.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                    #[test]
+                    fn miss_right() {
+                        let bb = test_bb();
+                        let r = Ray::new([1.1, 0., -1.1], [0., 0., 1.], 0.5);
+                        assert_eq!(bb.$name(r, T_MIN, T_MAX), None);
+                    }
+                }
+            )*
+        }
+    }
+
+    hit_test! {
+        hit_naive,
+        hit_simd,
+        hit_fast,
+        hit2,
+    }
+}

rtiow/renderer/src/bvh.rs

@@ -1,17 +1,15 @@
-use std;
+use std::{self, fmt, time::Instant};
-use std::fmt;
-use std::time::Instant;
 
 use log::info;
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::aabb::surrounding_box;
+use crate::{
-use crate::aabb::AABB;
+    aabb::{surrounding_box, AABB},
-use crate::hitable::Hit;
+    hitable::{Hit, HitRecord},
-use crate::hitable::HitRecord;
+    ray::Ray,
-use crate::ray::Ray;
+};
 
+#[derive(Debug)]
 enum BVHNode {
     Leaf(Box<dyn Hit>),
     Branch {
@@ -181,6 +179,7 @@ impl Hit for BVHNode {
     }
 }
 
+#[derive(Debug)]
 pub struct BVH {
     root: BVHNode,
 }
@@ -232,12 +231,13 @@ impl Hit for BVH {
 
 #[cfg(test)]
 mod tests {
-    use crate::aabb::AABB;
+    use crate::{
-    use crate::material::Lambertian;
+        aabb::AABB,
-    use crate::material::Metal;
+        material::{Lambertian, Metal},
-    use crate::sphere::Sphere;
+        sphere::Sphere,
-    use crate::texture::ConstantTexture;
+        texture::ConstantTexture,
-    use crate::vec3::Vec3;
+        vec3::Vec3,
+    };
 
     use super::*;
 

rtiow/renderer/src/bvh_triangles.rs

@@ -0,0 +1,711 @@
+/// Implementation based on blog post @
+/// https://jacco.ompf2.com/2022/04/13/how-to-build-a-bvh-part-1-basics/
+use std::f32::EPSILON;
+use std::fmt;
+
+use log::info;
+use stl::STL;
+
+use crate::{
+    aabb::AABB,
+    hitable::{Hit, HitRecord},
+    material::Material,
+    ray::Ray,
+    vec3::{cross, dot, Vec3},
+};
+
+#[derive(Debug, PartialEq)]
+struct BVHNode {
+    aabb: AABB,
+    // When tri_count==0, left_first holds the left child's index in bvh_nodes. When >0 left_first
+    // holds the index for the first triangle in triangles.
+    left_first: u32,
+    tri_count: u32,
+}
+
+impl BVHNode {
+    fn is_leaf(&self) -> bool {
+        self.tri_count > 0
+    }
+
+    fn cost(&self) -> f32 {
+        let area = self.aabb.area();
+        self.tri_count as f32 * area
+    }
+}
+
+#[derive(Clone, PartialEq)]
+pub struct Triangle {
+    centroid: Vec3,
+    verts: [Vec3; 3],
+}
+impl fmt::Debug for Triangle {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "Tri: <{}, {}, {}> @ {}",
+            self.verts[0], self.verts[1], self.verts[2], self.centroid
+        )
+    }
+}
+
+pub struct BVHTriangles<M>
+where
+    M: Material,
+{
+    pub triangles: Vec<Triangle>,
+    triangle_index: Vec<usize>,
+    material: M,
+    bvh_nodes: Vec<BVHNode>,
+}
+
+#[derive(Debug, Default)]
+struct Bin {
+    bounds: AABB,
+    tri_count: usize,
+}
+
+impl<M> fmt::Debug for BVHTriangles<M>
+where
+    M: Material,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{} triangles", self.triangles.len())?;
+        if f.alternate() {
+            writeln!(f)?;
+        }
+        for (i, t) in self.triangles.iter().enumerate() {
+            if f.alternate() {
+                write!(f, "\t")?;
+            }
+            write!(f, "{i:>3} {:?} ", t)?;
+            if f.alternate() {
+                writeln!(f)?;
+            }
+        }
+        if f.alternate() {
+            writeln!(f)?;
+        }
+        for (i, n) in self.bvh_nodes.iter().enumerate() {
+            write!(f, "N[{i}] {n:?}")?;
+            if f.alternate() {
+                writeln!(f)?;
+            }
+            let n = &self.bvh_nodes[i];
+            if n.is_leaf() {
+                for t_idx in n.left_first..(n.left_first + n.tri_count) {
+                    if f.alternate() {
+                        write!(f, "\t")?;
+                    }
+                    write!(f, "{:?} ", self.triangles[t_idx as usize])?;
+                    if f.alternate() {
+                        writeln!(f)?;
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+struct SplitCost {
+    pos: f32,
+    axis: usize,
+    cost: f32,
+}
+
+const ROOT_NODE_IDX: usize = 0;
+impl<M> BVHTriangles<M>
+where
+    M: Material,
+{
+    pub fn new(stl: &STL, material: M, scale_factor: f32) -> BVHTriangles<M> {
+        let now = std::time::Instant::now();
+
+        assert_eq!(std::mem::size_of::<BVHNode>(), 32);
+        let div3 = 1. / 3.;
+        let triangles: Vec<_> = stl
+            .triangles
+            .iter()
+            .map(|t| {
+                let v0 = t.verts[0] * scale_factor;
+                let v1 = t.verts[1] * scale_factor;
+                let v2 = t.verts[2] * scale_factor;
+                let centroid = (v0 + v1 + v2) * div3;
+                Triangle {
+                    centroid,
+                    verts: [v0, v1, v2],
+                }
+            })
+            .collect();
+        let triangle_index = (0..triangles.len()).collect();
+
+        let n = 2 * triangles.len() - 2;
+        let bvh_nodes = Vec::with_capacity(n);
+        let mut bvh = BVHTriangles {
+            triangles,
+            triangle_index,
+            bvh_nodes,
+            material,
+        };
+        bvh.build_bvh();
+        info!(
+            "BVHTriangles build time {:0.3}s",
+            now.elapsed().as_secs_f32()
+        );
+        struct Stats {
+            nodes: usize,
+            leafs: usize,
+            min_tris: u32,
+            max_tris: u32,
+        }
+        impl Default for Stats {
+            fn default() -> Self {
+                Stats {
+                    nodes: 0,
+                    leafs: 0,
+                    min_tris: u32::MAX,
+                    max_tris: u32::MIN,
+                }
+            }
+        }
+        let stats = bvh.bvh_nodes.iter().fold(Stats::default(), |mut stats, n| {
+            stats.nodes += 1;
+            if n.is_leaf() {
+                stats.leafs += 1;
+                stats.min_tris = n.tri_count.min(stats.min_tris);
+                stats.max_tris = n.tri_count.max(stats.max_tris);
+            }
+            stats
+        });
+        info!("BVHTriangles build stats:");
+        info!("  Nodes:   {}", stats.nodes);
+        info!("  Leaves:  {}", stats.leafs);
+        info!("  Tris:    {}", bvh.triangles.len());
+        info!("  Min Tri: {}", stats.min_tris);
+        info!("  Max Tri: {}", stats.max_tris);
+        info!("  Avg Tri: {}", bvh.triangles.len() / stats.leafs);
+        info!("  Predict: {}", bvh.bvh_nodes.capacity());
+        info!("  Actual:  {}", bvh.bvh_nodes.len());
+        info!(
+            "  Savings:  {} bytes",
+            (bvh.bvh_nodes.capacity() - bvh.bvh_nodes.len()) * std::mem::size_of::<BVHNode>()
+        );
+        bvh.bvh_nodes.shrink_to_fit();
+        //dbg!(&bvh);
+        bvh
+    }
+
+    fn build_bvh(&mut self) {
+        // assign all triangles to root node
+        let root = BVHNode {
+            aabb: AABB::default(),
+            left_first: 0,
+            tri_count: self.triangles.len() as u32,
+        };
+        self.bvh_nodes.push(root);
+        self.update_node_bounds(ROOT_NODE_IDX);
+        // subdivide recursively
+        self.subdivide(ROOT_NODE_IDX);
+    }
+    fn update_node_bounds(&mut self, node_idx: usize) {
+        let node = &mut self.bvh_nodes[node_idx];
+        let mut aabb_min: Vec3 = f32::MAX.into();
+        let mut aabb_max: Vec3 = f32::MIN.into();
+        for i in node.left_first..(node.left_first + node.tri_count) {
+            let leaf_tri_idx = self.triangle_index[i as usize];
+            let leaf_tri = &self.triangles[leaf_tri_idx];
+            aabb_min = vec3::min(aabb_min, leaf_tri.verts[0]);
+            aabb_min = vec3::min(aabb_min, leaf_tri.verts[1]);
+            aabb_min = vec3::min(aabb_min, leaf_tri.verts[2]);
+            aabb_max = vec3::max(aabb_max, leaf_tri.verts[0]);
+            aabb_max = vec3::max(aabb_max, leaf_tri.verts[1]);
+            aabb_max = vec3::max(aabb_max, leaf_tri.verts[2]);
+        }
+        node.aabb = AABB::new(aabb_min, aabb_max);
+    }
+
+    fn find_best_split_plane(&self, node: &BVHNode) -> SplitCost {
+        let mut best = SplitCost {
+            pos: 0.,
+            cost: f32::MAX,
+            axis: usize::MAX,
+        };
+
+        for axis in 0..3 {
+            let mut bounds_min = f32::MAX;
+            let mut bounds_max = f32::MIN;
+
+            for i in 0..node.tri_count {
+                let triangle = &self.triangles[self.triangle_index[(node.left_first + i) as usize]];
+                bounds_min = bounds_min.min(triangle.centroid[axis]);
+                bounds_max = bounds_max.max(triangle.centroid[axis]);
+            }
+
+            if bounds_min == bounds_max {
+                continue;
+            }
+
+            const NUM_BINS: usize = 8;
+            let mut bins: Vec<_> = (0..NUM_BINS)
+                .map(|_| Bin {
+                    bounds: AABB::infinite(),
+                    tri_count: 0,
+                })
+                .collect();
+            let scale = bins.len() as f32 / (bounds_max - bounds_min);
+            // populate the bins
+            for i in 0..node.tri_count {
+                let triangle = &self.triangles[self.triangle_index[(node.left_first + i) as usize]];
+                let bin_idx = (triangle.centroid[axis] - bounds_min) * scale;
+                let bin_idx = (bins.len() - 1).min(bin_idx as usize);
+
+                bins[bin_idx].tri_count += 1;
+                bins[bin_idx].bounds.grow(triangle.verts[0]);
+                bins[bin_idx].bounds.grow(triangle.verts[1]);
+                bins[bin_idx].bounds.grow(triangle.verts[2]);
+            }
+
+            // gather data for the 7 planes between the 8 bins
+            let mut left_area: Vec<_> = (0..bins.len() - 1).map(|_| 0.).collect();
+            let mut right_area: Vec<_> = (0..bins.len() - 1).map(|_| 0.).collect();
+            let mut left_count: Vec<_> = (0..bins.len() - 1).map(|_| 0).collect();
+            let mut right_count: Vec<_> = (0..bins.len() - 1).map(|_| 0).collect();
+            let mut left_box = AABB::infinite();
+            let mut right_box = AABB::infinite();
+            let mut left_sum = 0;
+            let mut right_sum = 0;
+            for i in 0..(bins.len() - 1) {
+                left_sum += bins[i].tri_count;
+                left_count[i] = left_sum;
+                left_box.grow(bins[i].bounds.min());
+                left_box.grow(bins[i].bounds.max());
+                left_area[i] = left_box.area();
+
+                right_sum += bins[bins.len() - 1 - i].tri_count;
+                right_count[bins.len() - 2 - i] = right_sum;
+                right_box.grow(bins[bins.len() - 1 - i].bounds.min());
+                right_box.grow(bins[bins.len() - 1 - i].bounds.max());
+                right_area[bins.len() - 2 - i] = right_box.area();
+            }
+
+            let scale = (bounds_max - bounds_min) / bins.len() as f32;
+            // calculate SAH cost for the 7 planes
+            for i in 0..(bins.len() - 1) {
+                let plane_cost =
+                    left_count[i] as f32 * left_area[i] + right_count[i] as f32 * right_area[i];
+                if plane_cost < best.cost {
+                    best.axis = axis;
+                    best.pos = bounds_min + scale * (i as f32 + 1.);
+                    best.cost = plane_cost;
+                }
+            }
+        }
+        best
+    }
+
+    fn subdivide(&mut self, idx: usize) {
+        let (left_first, tri_count, left_count, i) = {
+            let node = &self.bvh_nodes[idx];
+            let split = self.find_best_split_plane(&node);
+            let no_split_cost = node.cost();
+            // Stop subdividing if it isn't getting any better.
+            if split.cost >= no_split_cost {
+                return;
+            }
+
+            // Split the group in two halves.
+            let mut i = node.left_first as isize;
+            let mut j = i + node.tri_count as isize - 1;
+            while i <= j {
+                if self.triangles[self.triangle_index[i as usize]].centroid[split.axis] < split.pos
+                {
+                    i += 1;
+                } else {
+                    self.triangles.swap(
+                        self.triangle_index[i as usize],
+                        self.triangle_index[j as usize],
+                    );
+                    j -= 1;
+                }
+            }
+
+            // Create child nodes for each half.
+            let left_count = i as u32 - node.left_first;
+            if left_count == 0 || left_count == node.tri_count {
+                return;
+            }
+            (node.left_first, node.tri_count, left_count, i)
+        };
+
+        // create child nodes
+        let left_child_idx = self.bvh_nodes.len() as u32;
+        let right_child_idx = left_child_idx + 1 as u32;
+        let left = BVHNode {
+            aabb: AABB::default(),
+            left_first,
+            tri_count: left_count as u32,
+        };
+        let right = BVHNode {
+            aabb: AABB::default(),
+            left_first: i as u32,
+            tri_count: (tri_count - left_count) as u32,
+        };
+        self.bvh_nodes.push(left);
+        self.bvh_nodes.push(right);
+        let node = &mut self.bvh_nodes[idx];
+        node.left_first = left_child_idx;
+        node.tri_count = 0;
+
+        // Recurse
+        self.update_node_bounds(left_child_idx as usize);
+        self.subdivide(left_child_idx as usize);
+        self.update_node_bounds(right_child_idx as usize);
+        self.subdivide(right_child_idx as usize);
+    }
+
+    fn intersect_bvh(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        let mut node = &self.bvh_nodes[ROOT_NODE_IDX];
+        let mut stack = Vec::with_capacity(2);
+        let mut nearest = None;
+        loop {
+            if node.is_leaf() {
+                let canditate = (node.left_first..(node.left_first + node.tri_count))
+                    // Map from idx to Triangle
+                    .map(|idx| &self.triangles[self.triangle_index[idx as usize]])
+                    // Try to hit all triangles for this node, filtering out misses.
+                    .filter_map(|tri| intersect_tri(r, &tri))
+                    // Find the nearest hit (if any).
+                    .min_by(|a, b| a.t.partial_cmp(&b.t).unwrap());
+
+                // merge candidate with nearest.
+                nearest = match (&canditate, &nearest) {
+                    (Some(_), None) => canditate,
+                    (None, Some(_)) => nearest,
+                    (Some(c), Some(n)) => {
+                        //info!("merging {c:#?} and {n:#?}");
+                        if c.t < n.t {
+                            canditate
+                        } else {
+                            nearest
+                        }
+                    }
+                    (None, None) => None,
+                };
+                if stack.is_empty() {
+                    break;
+                }
+                node = stack.pop().unwrap();
+                continue;
+            }
+
+            let child1 = &self.bvh_nodes[node.left_first as usize];
+            let child2 = &self.bvh_nodes[node.left_first as usize + 1];
+            let dist1 = child1.aabb.hit_distance(r, t_min, t_max);
+            let dist2 = child2.aabb.hit_distance(r, t_min, t_max);
+            // Swap c1/c2 & d1/d2 based on d1/d2.
+            let (child1, child2, dist1, dist2) = match (dist1, dist2) {
+                (Some(d1), Some(d2)) if d1 > d2 => (child2, child1, dist2, dist1),
+                (None, Some(_)) => (child2, child1, dist2, dist1),
+                _ => (child1, child2, dist1, dist2),
+            };
+
+            // dist1/child1 should now be the nearest hit.
+
+            // If we missed dist1/child1, then we implicitly missed dist2/child2, so pop a child
+            // from the stack or exit the function.
+            if dist1.is_none() {
+                if stack.is_empty() {
+                    break;
+                }
+                node = stack.pop().unwrap();
+            } else {
+                // We hit child1, so process it next.
+                node = child1;
+                // If we also hit child2 save it on the stack so we can process it later.
+                if dist2.is_some() {
+                    stack.push(child2);
+                }
+            }
+        }
+        nearest
+            .and_then(|rtr: RayTriangleResult| Some(rtr.hit_record_with_material(&self.material)))
+    }
+}
+
+/// Based on https://www.scratchapixel.com/lessons/3d-basic-rendering/ray-tracing-rendering-a-triangle/moller-trumbore-ray-triangle-intersection.html
+fn intersect_tri(r: Ray, tri: &Triangle) -> Option<RayTriangleResult> {
+    // #ifdef MOLLER_TRUMBORE
+    //     Vec3f v0v1 = v1 - v0;
+    //     Vec3f v0v2 = v2 - v0;
+    //     Vec3f pvec = dir.crossProduct(v0v2);
+    //     float det = v0v1.dotProduct(pvec);
+    // #ifdef CULLING
+    //     // if the determinant is negative, the triangle is 'back facing'
+    //     // if the determinant is close to 0, the ray misses the triangle
+    //     if (det < kEpsilon) return false;
+    // #else
+    //     // ray and triangle are parallel if det is close to 0
+    //     if (fabs(det) < kEpsilon) return false;
+    // #endif
+    //     float invDet = 1 / det;
+    //
+    //     Vec3f tvec = orig - v0;
+    //     u = tvec.dotProduct(pvec) * invDet;
+    //     if (u < 0 || u > 1) return false;
+    //
+    //     Vec3f qvec = tvec.crossProduct(v0v1);
+    //     v = dir.dotProduct(qvec) * invDet;
+    //     if (v < 0 || u + v > 1) return false;
+    //
+    //     t = v0v2.dotProduct(qvec) * invDet;
+    //
+    let v0 = tri.verts[0];
+    let v1 = tri.verts[1];
+    let v2 = tri.verts[2];
+
+    let v0v1 = v1 - v0;
+    let v0v2 = v2 - v0;
+    let p = cross(r.direction, v0v2);
+    let det = dot(v0v1, p);
+    if det.abs() < EPSILON {
+        return None;
+    }
+
+    let inv_det = 1. / det;
+
+    let t = r.origin - v0;
+    let u = dot(t, p) * inv_det;
+    if u < 0. || u > 1. {
+        return None;
+    }
+
+    let q = cross(t, v0v1);
+    let v = dot(r.direction, q) * inv_det;
+    if v < 0. || u + v > 1. {
+        return None;
+    }
+    let t = dot(v0v2, q) * inv_det;
+
+    if t > EPSILON {
+        return Some(RayTriangleResult {
+            t,
+            p: r.point_at_parameter(t),
+            tri: tri.clone(),
+        });
+    }
+    None
+}
+
+impl<M> Hit for BVHTriangles<M>
+where
+    M: Material,
+{
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        self.intersect_bvh(r, t_min, t_max)
+    }
+
+    fn bounding_box(&self, _t_min: f32, _t_max: f32) -> Option<AABB> {
+        Some(self.bvh_nodes[ROOT_NODE_IDX].aabb)
+    }
+}
+
+#[derive(Debug)]
+struct RayTriangleResult {
+    t: f32,
+    p: Vec3,
+    tri: Triangle,
+}
+
+impl RayTriangleResult {
+    fn hit_record_with_material<'m>(self, material: &'m dyn Material) -> HitRecord<'m> {
+        // We don't support UV (yet?).
+        let uv = (0.5, 0.5);
+        let v0 = self.tri.verts[0];
+        let v1 = self.tri.verts[1];
+        let v2 = self.tri.verts[2];
+
+        let v0v1 = v1 - v0;
+        let v0v2 = v2 - v0;
+        let normal = cross(v0v1, v0v2).unit_vector();
+        //println!("hit triangle {tri:?}");
+        HitRecord {
+            t: self.t,
+            uv,
+            p: self.p,
+            normal,
+            material,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{
+        bvh_triangles::BVHTriangles,
+        cuboid::Cuboid,
+        hitable::Hit,
+        material::{Dielectric, Lambertian},
+        ray::Ray,
+        texture::ConstantTexture,
+    };
+    use pretty_assertions::assert_eq;
+    use proptest::prelude::*;
+    use std::{
+        io::{BufReader, Cursor},
+        sync::Arc,
+    };
+    use stl::STL;
+
+    #[test]
+    fn compare_cuboid() {
+        let c = Cuboid::new(
+            [0., 0., 0.].into(),
+            [20., 20., 20.].into(),
+            Arc::new(Dielectric::new(1.5)),
+        );
+        let stl_cube = STL::parse(
+            BufReader::new(Cursor::new(include_bytes!("../stls/cube.stl"))),
+            false,
+        )
+        .expect("failed to parse cube");
+
+        let s = BVHTriangles::new(
+            &stl_cube,
+            Dielectric::new(1.5),
+            //Metal::new(Vec3::new(0.8, 0.8, 0.8), 0.2),
+            //Lambertian::new(ConstantTexture::new(Vec3::new(1.0, 0.2, 0.2))),
+        );
+        //dbg!(&s);
+        let mut rays: Vec<_> = (1..20)
+            .flat_map(|y| {
+                (1..20).flat_map(move |x| {
+                    let x = x as f32;
+                    let y = y as f32;
+                    vec![
+                        // Outward in angle
+                        Ray::new([-1., x, y], [1., 0., 0.], 0.),
+                        Ray::new([21., x, y], [-1., 0., 0.], 0.),
+                        Ray::new([x, -1., y], [0., 1., 0.], 0.),
+                        Ray::new([x, 21., y], [0., -1., 0.], 0.),
+                        Ray::new([x, y, -1.], [0., 0., 1.], 0.),
+                        Ray::new([x, y, 21.], [0., 0., -1.], 0.),
+                        // Inward out (
+                        Ray::new([x, y, 10.], [1., 0., 0.], 0.),
+                        Ray::new([x, y, 10.], [-1., 0., 0.], 0.),
+                        Ray::new([x, 10., y], [1., 0., 0.], 0.),
+                        Ray::new([x, 10., y], [-1., 0., 0.], 0.),
+                        Ray::new([10., x, y], [1., 0., 0.], 0.),
+                        Ray::new([10., x, y], [-1., 0., 0.], 0.),
+                        Ray::new([x, y, 10.], [0., 1., 0.], 0.),
+                        Ray::new([x, y, 10.], [0., -1., 0.], 0.),
+                        Ray::new([x, 10., y], [0., 1., 0.], 0.),
+                        Ray::new([x, 10., y], [0., -1., 0.], 0.),
+                        Ray::new([10., x, y], [0., 1., 0.], 0.),
+                        Ray::new([10., x, y], [0., -1., 0.], 0.),
+                        Ray::new([x, y, 10.], [0., 0., 1.], 0.),
+                        Ray::new([x, y, 10.], [0., 0., -1.], 0.),
+                        Ray::new([x, 10., y], [0., 0., 1.], 0.),
+                        Ray::new([x, 10., y], [0., 0., -1.], 0.),
+                        Ray::new([10., x, y], [0., 0., 1.], 0.),
+                        Ray::new([10., x, y], [0., 0., -1.], 0.),
+                    ]
+                    .into_iter()
+                })
+            })
+            .collect();
+        if false {
+            // Outward in at an angle.
+            let sqrt2 = 2f32.sqrt();
+            rays.extend(vec![
+                Ray::new([-1., 10., 10.], [sqrt2, sqrt2, 0.], 0.),
+                Ray::new([-1., 10., 10.], [sqrt2, -sqrt2, 0.], 0.),
+                Ray::new([-1., 10., 10.], [sqrt2, 0., sqrt2], 0.),
+                Ray::new([-1., 10., 10.], [sqrt2, 0., -sqrt2], 0.),
+            ]);
+        }
+
+        for r in rays.into_iter() {
+            let c_hit = c
+                .hit(r, 0., f32::MAX)
+                .expect(&format!("c_hit missed {r:#?}"));
+            let s_hit = s
+                .hit(r, 0., f32::MAX)
+                .expect(&format!("s_hit missed {r:#?}"));
+            assert!(
+                (c_hit.t - s_hit.t).abs() < EPSILON,
+                "{r:?} [t] c_hit: {c_hit:#?}, s_hit: {s_hit:#?}"
+            );
+            // uv isn't valid for BVHTriangles.
+            // assert_eq!( c_hit.uv, s_hit.uv, "{i}: [uv] c_hit: {c_hit:?}, s_hit: {s_hit:?}");
+            assert_eq!(
+                c_hit.p, s_hit.p,
+                "{r:?}: [p] c_hit: {c_hit:#?}, s_hit: {s_hit:#?}"
+            );
+            assert_eq!(
+                c_hit.normal, s_hit.normal,
+                "{r:?}: [normal] c_hit: {c_hit:?}, s_hit: {s_hit:?}"
+            );
+        }
+    }
+
+    proptest! {
+        // TODO(wathiede): make this work.
+        //#[test]
+        fn compare_cuboid_proptest(
+            ox in -20.0f32..40.0,
+            oy in -20.0f32..40.0,
+            oz in -20.0f32..40.0,
+            dx in -1.0f32..1.0,
+            dy in -1.0f32..1.0,
+            dz in -1.0f32..1.0,
+        ) {
+            let r = Ray::new([ox,oy,oz].into(), Vec3::new(dx, dy, dz).unit_vector(), 0.5);
+            let c = Cuboid::new(
+                [0., 0., 0.].into(),
+                [20., 20., 20.].into(),
+                Arc::new(Dielectric::new(1.5)),
+            );
+            let stl_cube = STL::parse(
+                BufReader::new(Cursor::new(include_bytes!("../stls/cube.stl"))),
+                false,
+            )
+                .expect("failed to parse cube");
+
+            let s = BVHTriangles::new(
+                &stl_cube,
+                Dielectric::new(1.5),
+                //Metal::new(Vec3::new(0.8, 0.8, 0.8), 0.2),
+                //Lambertian::new(ConstantTexture::new(Vec3::new(1.0, 0.2, 0.2))),
+            );
+
+            let c_hit = c .hit(r, 0., f32::MAX);
+            let s_hit = s .hit(r, 0., f32::MAX);
+
+            match (c_hit, s_hit) {
+                (Some(_), None)=>assert!(false, "hit cuboid but not STL"),
+                (None, Some(_))=>assert!(false, "hit STL but not cuboid"),
+                (Some(c_hit), Some(s_hit))=> {
+                    assert!(
+                        (c_hit.t - s_hit.t).abs() < 0.00001,
+                        "{r:?} [t] c_hit: {c_hit:#?}, s_hit: {s_hit:#?}"
+                    );
+                    // uv isn't valid for BVHTriangles.
+                    // assert_eq!( c_hit.uv, s_hit.uv, "{i}: [uv] c_hit: {c_hit:?}, s_hit: {s_hit:?}");
+                    assert_eq!(
+                        c_hit.p, s_hit.p,
+                        "{r:?}: [p] c_hit: {c_hit:#?}, s_hit: {s_hit:#?}"
+                    );
+                    assert_eq!(
+                        c_hit.normal, s_hit.normal,
+                        "{r:?}: [normal] c_hit: {c_hit:?}, s_hit: {s_hit:?}"
+                    );
+                },
+                // It's okay if they both miss.
+                (None,None)=>(),
+            }
+        }
+    }
+}

rtiow/renderer/src/camera.rs

@@ -1,11 +1,11 @@
 use std::f32::consts::PI;
 
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::ray::Ray;
+use crate::{
-use crate::vec3::cross;
+    ray::Ray,
-use crate::vec3::Vec3;
+    vec3::{cross, Vec3},
+};
 
 fn random_in_unit_disk() -> Vec3 {
     let mut rng = rand::thread_rng();
@@ -18,6 +18,7 @@ fn random_in_unit_disk() -> Vec3 {
     }
 }
 
+#[derive(Debug)]
 pub struct Camera {
     origin: Vec3,
     lower_left_corner: Vec3,

rtiow/renderer/src/colors.rs

@@ -0,0 +1,46 @@
+use rand::{self, Rng};
+
+use crate::vec3::Vec3;
+
+// HSV values in [0..1]
+// returns [r, g, b] values from 0 to 255
+//From https://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/
+pub fn hsv_to_rgb(h: f32, s: f32, v: f32) -> Vec3 {
+    let h_i = (h * 6.) as i32;
+    let f = h * 6. - h_i as f32;
+    let p = v * (1. - s);
+    let q = v * (1. - f * s);
+    let t = v * (1. - (1. - f) * s);
+    match h_i {
+        0 => Vec3::new(v, t, p),
+        1 => Vec3::new(q, v, p),
+        2 => Vec3::new(p, v, t),
+        3 => Vec3::new(p, q, v),
+        4 => Vec3::new(t, p, v),
+        5 => Vec3::new(v, p, q),
+        _ => panic!("Unknown H value {}", h_i),
+    }
+}
+
+pub fn generate_rainbow(num: usize) -> Vec<Vec3> {
+    (0..num)
+        .map(|n| {
+            let h = n as f32 / num as f32;
+            hsv_to_rgb(h, 0.99, 0.99)
+        })
+        .collect()
+}
+pub fn generate_palette(num: usize) -> Vec<Vec3> {
+    let mut rng = rand::thread_rng();
+    let mut random = || rng.gen();
+    // use golden ratio
+    let golden_ratio_conjugate = 0.618_034;
+    let mut h = random();
+    (0..num)
+        .map(|_| {
+            h += golden_ratio_conjugate;
+            h %= 1.0;
+            hsv_to_rgb(h, 0.99, 0.99)
+        })
+        .collect()
+}

rtiow/renderer/src/constant_medium.rs

@@ -1,16 +1,17 @@
 use std;
 
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::material::Isotropic;
+    material::Isotropic,
-use crate::ray::Ray;
+    ray::Ray,
-use crate::texture::Texture;
+    texture::Texture,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
+#[derive(Debug)]
 pub struct ConstantMedium<H, T>
 where
     H: Hit,

rtiow/renderer/src/cuboid.rs

@@ -1,17 +1,17 @@
 use std::sync::Arc;
 
-use crate::aabb::AABB;
+use crate::{
-use crate::flip_normals::FlipNormals;
+    aabb::AABB,
-use crate::hitable::Hit;
+    flip_normals::FlipNormals,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::hitable_list::HitableList;
+    hitable_list::HitableList,
-use crate::material::Material;
+    material::Material,
-use crate::ray::Ray;
+    ray::Ray,
-use crate::rect::XYRect;
+    rect::{XYRect, XZRect, YZRect},
-use crate::rect::XZRect;
+    vec3::Vec3,
-use crate::rect::YZRect;
+};
-use crate::vec3::Vec3;
 
+#[derive(Debug)]
 pub struct Cuboid {
     p_min: Vec3,
     p_max: Vec3,
@@ -22,6 +22,9 @@ impl Cuboid {
     // This clippy doesn't work right with Arc.
     #[allow(clippy::needless_pass_by_value)]
     pub fn new(p_min: Vec3, p_max: Vec3, material: Arc<dyn Material>) -> Cuboid {
+        assert!(p_min.x <= p_max.x);
+        assert!(p_min.y <= p_max.y);
+        assert!(p_min.z <= p_max.z);
         Cuboid {
             p_min,
             p_max,

rtiow/renderer/src/debug_hit.rs

@@ -0,0 +1,44 @@
+use crate::{
+    aabb::AABB,
+    hitable::{Hit, HitRecord},
+    material::Lambertian,
+    ray::Ray,
+};
+
+#[derive(Debug)]
+pub struct DebugHit<H>
+where
+    H: Hit,
+{
+    hitable: H,
+    material: Lambertian<[f32; 3]>,
+}
+
+impl<H> DebugHit<H>
+where
+    H: Hit,
+{
+    pub fn new(hitable: H) -> DebugHit<H>
+where {
+        DebugHit {
+            hitable,
+            material: Lambertian::new([0.2, 0.2, 0.2]),
+        }
+    }
+}
+
+impl<H> Hit for DebugHit<H>
+where
+    H: Hit,
+{
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        if let Some(hit) = self.hitable.hit(r, t_min, t_max) {
+            return Some(HitRecord { t: hit.t, ..hit });
+        }
+        None
+    }
+
+    fn bounding_box(&self, t_min: f32, t_max: f32) -> Option<AABB> {
+        self.hitable.bounding_box(t_min, t_max)
+    }
+}

rtiow/renderer/src/flip_normals.rs

@@ -1,8 +1,10 @@
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::ray::Ray;
+    ray::Ray,
+};
 
+#[derive(Debug)]
 pub struct FlipNormals<H>
 where
     H: Hit,

rtiow/renderer/src/glowybox.rs

@@ -0,0 +1,139 @@
+use std::sync::Arc;
+
+use crate::{
+    aabb::AABB,
+    cuboid::Cuboid,
+    hitable::{Hit, HitRecord},
+    material::Material,
+    ray::Ray,
+    vec3::Vec3,
+};
+
+#[derive(Debug)]
+pub struct Glowybox {
+    p_min: Vec3,
+    p_max: Vec3,
+    main: Cuboid,
+    edges: [Cuboid; 12],
+}
+
+impl Glowybox {
+    // This clippy doesn't work right with Arc.
+    #[allow(clippy::needless_pass_by_value)]
+    pub fn new(
+        p_min: Vec3,
+        p_max: Vec3,
+        edge_thickness: f32,
+        main_material: Arc<dyn Material>,
+        edge_material: Arc<dyn Material>,
+    ) -> Glowybox {
+        assert!(p_min.x < p_max.x);
+        assert!(p_min.y < p_max.y);
+        assert!(p_min.z < p_max.z);
+        let main = Cuboid::new(p_min, p_max, main_material);
+        // Top edges
+        let ht = edge_thickness / 2.;
+        let edges = [
+            // Top edges
+            Cuboid::new(
+                [p_min.x - ht, p_max.y - ht, p_min.z - ht].into(),
+                [p_min.x + ht, p_max.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_min.x - ht, p_max.y - ht, p_min.z - ht].into(),
+                [p_max.x + ht, p_max.y + ht, p_min.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_max.x - ht, p_max.y - ht, p_min.z - ht].into(),
+                [p_max.x + ht, p_max.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_min.x - ht, p_max.y - ht, p_max.z - ht].into(),
+                [p_max.x + ht, p_max.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            // Bottom edges
+            Cuboid::new(
+                [p_min.x - ht, p_min.y - ht, p_min.z - ht].into(),
+                [p_min.x + ht, p_min.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_min.x - ht, p_min.y - ht, p_min.z - ht].into(),
+                [p_max.x + ht, p_min.y + ht, p_min.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_max.x - ht, p_min.y - ht, p_min.z - ht].into(),
+                [p_max.x + ht, p_min.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_min.x - ht, p_min.y - ht, p_max.z - ht].into(),
+                [p_max.x + ht, p_min.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            // Middle edges
+            Cuboid::new(
+                [p_min.x - ht, p_min.y - ht, p_min.z - ht].into(),
+                [p_min.x + ht, p_max.y + ht, p_min.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_min.x - ht, p_min.y - ht, p_max.z - ht].into(),
+                [p_min.x + ht, p_max.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_max.x - ht, p_min.y - ht, p_min.z - ht].into(),
+                [p_max.x + ht, p_max.y + ht, p_min.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+            Cuboid::new(
+                [p_max.x - ht, p_min.y - ht, p_max.z - ht].into(),
+                [p_max.x + ht, p_max.y + ht, p_max.z + ht].into(),
+                Arc::clone(&edge_material),
+            ),
+        ];
+        let p_min = [p_min.x - ht, p_min.y - ht, p_min.z - ht].into();
+        let p_max = [p_max.x + ht, p_max.y + ht, p_max.z + ht].into();
+        Glowybox {
+            p_min,
+            p_max,
+            main,
+            edges,
+        }
+    }
+}
+
+impl Hit for Glowybox {
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        let mut edge_hit = None;
+        for edge in &self.edges {
+            if let Some(hit) = edge.hit(r, t_min, t_max) {
+                edge_hit = Some(hit);
+                break;
+            }
+        }
+        let main_hit = self.main.hit(r, t_min, t_max);
+        match (edge_hit, main_hit) {
+            (Some(ehit), Some(mhit)) => {
+                if mhit.t < ehit.t {
+                    Some(mhit)
+                } else {
+                    Some(ehit)
+                }
+            }
+            (Some(ehit), None) => Some(ehit),
+            (None, Some(mhit)) => Some(mhit),
+            _ => None,
+        }
+    }
+
+    fn bounding_box(&self, _t_min: f32, _t_max: f32) -> Option<AABB> {
+        Some(AABB::new(self.p_min, self.p_max))
+    }
+}

rtiow/renderer/src/hitable.rs

@@ -1,10 +1,8 @@
-use std::sync::Arc;
+use std::{fmt::Debug, sync::Arc};
 
-use crate::aabb::AABB;
+use crate::{aabb::AABB, material::Material, ray::Ray, vec3::Vec3};
-use crate::material::Material;
-use crate::ray::Ray;
-use crate::vec3::Vec3;
 
+#[derive(Debug)]
 pub struct HitRecord<'m> {
     pub t: f32,
     pub uv: (f32, f32),
@@ -13,7 +11,7 @@ pub struct HitRecord<'m> {
     pub material: &'m dyn Material,
 }
 
-pub trait Hit: Send + Sync {
+pub trait Hit: Send + Sync + Debug {
     fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord>;
     fn bounding_box(&self, t_min: f32, t_max: f32) -> Option<AABB>;
 }
@@ -26,3 +24,12 @@ impl Hit for Arc<dyn Hit> {
         (**self).bounding_box(t_min, t_max)
     }
 }
+
+impl Hit for Box<dyn Hit> {
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        (**self).hit(r, t_min, t_max)
+    }
+    fn bounding_box(&self, t_min: f32, t_max: f32) -> Option<AABB> {
+        (**self).bounding_box(t_min, t_max)
+    }
+}

rtiow/renderer/src/hitable_list.rs

@@ -1,13 +1,13 @@
 use std;
 
-use crate::aabb::surrounding_box;
+use crate::{
-use crate::aabb::AABB;
+    aabb::{surrounding_box, AABB},
-use crate::hitable::Hit;
+    hitable::{Hit, HitRecord},
-use crate::hitable::HitRecord;
+    ray::Ray,
-use crate::ray::Ray;
+    vec3::Vec3,
-use crate::vec3::Vec3;
+};
 
-#[derive(Default)]
+#[derive(Debug, Default)]
 pub struct HitableList {
     list: Vec<Box<dyn Hit>>,
 }

rtiow/renderer/src/human.rs

@@ -130,6 +130,12 @@ impl Formatter {
     }
 }
 
+impl Default for Formatter {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Scales {
     /// Instantiates a new `Scales` with SI keys
     pub fn new() -> Self {
@@ -199,7 +205,7 @@ impl Scales {
             }
         }
 
-        return 0.0;
+        0.0
     }
 
     fn to_scaled_value(&self, value: f64) -> ScaledValue {
@@ -221,3 +227,9 @@ impl Scales {
         }
     }
 }
+
+impl Default for Scales {
+    fn default() -> Self {
+        Self::new()
+    }
+}

rtiow/renderer/src/kdtree.rs

@@ -2,12 +2,14 @@ use std::fmt;
 
 use log::info;
 
-use crate::aabb::surrounding_box;
+use crate::{
-use crate::aabb::AABB;
+    aabb::{surrounding_box, AABB},
-use crate::hitable::Hit;
+    hitable::{Hit, HitRecord},
-use crate::hitable::HitRecord;
+    hitable_list::HitableList,
-use crate::ray::Ray;
+    ray::Ray,
+};
 
+#[derive(Debug)]
 pub enum KDTree {
     Leaf(Box<dyn Hit>),
     Branch {
@@ -102,6 +104,14 @@ impl KDTree {
             }),
             _ => panic!("Unreachable"),
         };
+        //info!("left_half {:?}", left_half);
+        //info!("right_half {:?}", right_half);
+        if left_half.is_empty() {
+            return KDTree::Leaf(Box::new(HitableList::new(right_half)));
+        };
+        if right_half.is_empty() {
+            return KDTree::Leaf(Box::new(HitableList::new(left_half)));
+        };
         KDTree::Branch {
             left: Box::new(KDTree::new(left_half, t_min, t_max)),
             right: Box::new(KDTree::new(right_half, t_min, t_max)),
@@ -146,7 +156,7 @@ fn print_tree(f: &mut fmt::Formatter, depth: usize, kdt: &KDTree) -> fmt::Result
 impl fmt::Display for KDTree {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         writeln!(f, "kd-tree")?;
-        print_tree(f, 1, &self)
+        print_tree(f, 1, self)
     }
 }
 impl Hit for KDTree {

rtiow/renderer/src/lib.rs

@@ -1,9 +1,13 @@
 pub mod aabb;
 pub mod bvh;
+pub mod bvh_triangles;
 pub mod camera;
+pub mod colors;
 pub mod constant_medium;
 pub mod cuboid;
+pub mod debug_hit;
 pub mod flip_normals;
+pub mod glowybox;
 pub mod hitable;
 pub mod hitable_list;
 pub mod human;
@@ -12,12 +16,15 @@ pub mod material;
 pub mod moving_sphere;
 pub mod noise;
 pub mod output;
+pub mod parser;
 pub mod ray;
 pub mod rect;
 pub mod renderer;
 pub mod rotate;
+pub mod scale;
 pub mod scenes;
 pub mod sphere;
 pub mod texture;
 pub mod translate;
+pub mod triangles;
 pub mod vec3;

rtiow/renderer/src/material.rs

@@ -1,13 +1,13 @@
-use std::sync::Arc;
+use std::{fmt::Debug, sync::Arc};
 
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::hitable::HitRecord;
+use crate::{
-use crate::ray::Ray;
+    hitable::HitRecord,
-use crate::texture::Texture;
+    ray::Ray,
-use crate::vec3::dot;
+    texture::Texture,
-use crate::vec3::Vec3;
+    vec3::{dot, Vec3},
+};
 
 fn random_in_unit_sphere() -> Vec3 {
     let mut rng = rand::thread_rng();
@@ -20,14 +20,14 @@ fn random_in_unit_sphere() -> Vec3 {
     }
 }
 
-#[derive(Default)]
+#[derive(Default, Debug)]
 pub struct ScatterResponse {
     pub scattered: Ray,
     pub attenutation: Vec3,
     pub reflected: bool,
 }
 
-pub trait Material: Send + Sync {
+pub trait Material: Send + Sync + Debug {
     fn scatter(&self, r_in: &Ray, rec: &HitRecord) -> ScatterResponse;
     fn emitted(&self, _u: f32, _v: f32, _p: Vec3) -> Vec3 {
         Vec3::new(0., 0., 0.)
@@ -52,6 +52,7 @@ impl Material for Box<dyn Material> {
     }
 }
 
+#[derive(Clone, Debug)]
 pub struct Isotropic<T>
 where
     T: Texture,
@@ -82,6 +83,7 @@ where
     }
 }
 
+#[derive(Clone, Debug)]
 pub struct Lambertian<T>
 where
     T: Texture,
@@ -113,6 +115,7 @@ where
     }
 }
 
+#[derive(Clone, Debug)]
 pub struct Metal {
     albedo: Vec3,
     fuzzy: f32,
@@ -167,6 +170,7 @@ fn schlick(cosine: f32, ref_idx: f32) -> f32 {
     r0 + (1. - r0) * (1. - cosine).powf(5.)
 }
 
+#[derive(Clone, Debug)]
 pub struct Dielectric {
     ref_idx: f32,
 }
@@ -213,6 +217,7 @@ impl Material for Dielectric {
     }
 }
 
+#[derive(Debug)]
 pub struct DiffuseLight<T>
 where
     T: Texture,
@@ -246,6 +251,20 @@ where
     }
 }
 
+#[derive(Debug)]
+pub struct DebugMaterial {}
+
+impl Material for DebugMaterial {
+    fn scatter(&self, _r_in: &Ray, rec: &HitRecord) -> ScatterResponse {
+        let dir = Vec3::new(0., -1., -1.).unit_vector();
+        ScatterResponse {
+            scattered: Ray::new(rec.p, dir, 0.),
+            attenutation: [1., 1., 1.].into(),
+            reflected: true,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

rtiow/renderer/src/moving_sphere.rs

@@ -1,13 +1,13 @@
-use crate::aabb::surrounding_box;
+use crate::{
-use crate::aabb::AABB;
+    aabb::{surrounding_box, AABB},
-use crate::hitable::Hit;
+    hitable::{Hit, HitRecord},
-use crate::hitable::HitRecord;
+    material::Material,
-use crate::material::Material;
+    ray::Ray,
-use crate::ray::Ray;
+    sphere::get_sphere_uv,
-use crate::sphere::get_sphere_uv;
+    vec3::{dot, Vec3},
-use crate::vec3::dot;
+};
-use crate::vec3::Vec3;
 
+#[derive(Debug)]
 pub struct MovingSphere<M>
 where
     M: Material,

rtiow/renderer/src/noise/lode.rs

@@ -2,10 +2,10 @@ use log::trace;
 /// Implements the concepts from https://lodev.org/cgtutor/randomnoise.html
 use rand;
 
-use crate::noise::NoiseSource;
+use crate::{noise::NoiseSource, vec3::Vec3};
-use crate::vec3::Vec3;
 
 const NOISE_SIZE: usize = 128;
+#[derive(Debug)]
 pub struct Lode {
     // Using fixed array causes stack overflow.
     noise: Vec<Vec<Vec<f32>>>, //[[[f32; NOISE_SIZE]; NOISE_SIZE]; NOISE_SIZE],

rtiow/renderer/src/noise/mod.rs

@@ -1,13 +1,13 @@
 pub mod lode;
 pub mod perlin;
 
-use std::f32::consts::PI;
+use std::{f32::consts::PI, fmt::Debug};
 
 use serde_derive::Deserialize;
 
 use crate::vec3::Vec3;
 
-pub trait NoiseSource: Send + Sync {
+pub trait NoiseSource: Send + Sync + Debug {
     /// value returns noise on the interval [0., 1.).
     fn value(&self, p: Vec3) -> f32;
 

rtiow/renderer/src/noise/perlin.rs

@@ -1,13 +1,14 @@
 // There are many math functions in this file, so we allow single letter variable names.
 #![allow(clippy::many_single_char_names)]
 use log::trace;
-use rand::seq::SliceRandom;
+use rand::{seq::SliceRandom, Rng};
-use rand::Rng;
 
-use crate::noise::NoiseSource;
+use crate::{
-use crate::vec3::dot;
+    noise::NoiseSource,
-use crate::vec3::Vec3;
+    vec3::{dot, Vec3},
+};
 
+#[derive(Debug)]
 pub struct Perlin {
     ran_vec: Vec<Vec3>,
     perm_x: Vec<usize>,
@@ -35,7 +36,7 @@ fn perlin_generate_perm<R>(rng: &mut R) -> Vec<usize>
 where
     R: Rng,
 {
-    let mut p: Vec<usize> = (0..256).map(|i| i).collect();
+    let mut p: Vec<usize> = (0..256).collect();
     p.shuffle(rng);
     p
 }

rtiow/renderer/src/output.rs

@@ -1,19 +1,20 @@
-use std::collections::HashMap;
+use std::{
-use std::fs::File;
+    collections::HashMap,
-use std::io::BufWriter;
+    fs::File,
-use std::path::Path;
+    io::BufWriter,
-use std::sync::Arc;
+    net::TcpStream,
-use std::sync::Mutex;
+    path::Path,
-use std::time;
+    sync::{Arc, Mutex},
+    time,
+};
 
 use chrono::Local;
 use image;
-use lazy_static::lazy_static;
 use log::info;
 use serde_derive::Serialize;
+use tev_client::{PacketCreateImage, PacketUpdateImage, TevClient};
 
-use crate::renderer::Scene;
+use crate::{renderer::Scene, vec3::Vec3};
-use crate::vec3::Vec3;
 
 // Main RGB image output from rendering the scene.
 pub const MAIN_IMAGE: &str = "@final";
@@ -24,10 +25,6 @@ pub const ADAPTIVE_DEPTH: &str = "adaptive_depth";
 // Grey scale showing rays cast per pixel.
 pub const RAYS_PER_PIXEL: &str = "rays_per_pixel";
 
-lazy_static! {
-    static ref DEBUGGER: Arc<Mutex<Debugger>> = Arc::new(Mutex::new(Debugger::new()));
-}
-
 #[derive(Serialize)]
 struct ImageMetadata {
     name: String,
@@ -74,43 +71,176 @@ impl Image {
     }
 }
 
-struct Debugger {
+pub struct OutputManager {
-    images: HashMap<String, (ImageType, Image)>,
+    images: Arc<Mutex<HashMap<String, (ImageType, Image)>>>,
+    tev_client: Option<Arc<Mutex<TevClient>>>,
 }
 
-impl Debugger {
+impl OutputManager {
-    fn new() -> Debugger {
+    pub fn new(tev_addr: &Option<String>) -> std::io::Result<OutputManager> {
-        Debugger {
+        let tev_client = if let Some(addr) = tev_addr {
-            images: HashMap::new(),
+            Some(Arc::new(Mutex::new(TevClient::wrap(TcpStream::connect(
-        }
+                addr,
+            )?))))
+        } else {
+            None
+        };
+        Ok(OutputManager {
+            images: Arc::new(Mutex::new(HashMap::new())),
+            tev_client,
+        })
     }
-}
 
-pub fn register_image(name: String, dimensions: (usize, usize), it: ImageType) {
+    pub fn register_image(&self, name: String, dimensions: (usize, usize), it: ImageType) {
-    let mut debugger = DEBUGGER.lock().unwrap();
+        let mut images = self.images.lock().unwrap();
-    debugger
+        images.insert(name.clone(), (it, Image::new(dimensions.0, dimensions.1)));
-        .images
+        self.tev_client.clone().map(|c| {
-        .insert(name, (it, Image::new(dimensions.0, dimensions.1)));
+            c.lock().unwrap().send(PacketCreateImage {
-}
+                image_name: &name,
+                grab_focus: false,
+                width: dimensions.0 as u32,
+                height: dimensions.1 as u32,
+                channel_names: &["R", "G", "B"],
+            })
+        });
+    }
 
-pub fn set_pixel(name: &str, x: usize, y: usize, pixel: Vec3) {
+    pub fn set_pixel(&self, name: &str, x: usize, y: usize, pixel: Vec3) {
-    let mut debugger = DEBUGGER.lock().unwrap();
+        let mut images = self.images.lock().unwrap();
-    let (_it, img) = debugger
+        let (_it, img) = images
-        .images
+            .get_mut(name)
-        .get_mut(name)
+            .unwrap_or_else(|| panic!("couldn't find image named '{}'", name));
-        .expect(&format!("couldn't find image named '{}'", name));
+        let y_inv = img.h - y - 1;
-    let y_inv = img.h - y - 1;
+        img.put_pixel(x, y_inv, pixel);
-    img.put_pixel(x, y_inv, pixel);
+        self.tev_client.clone().map(|c| {
-}
+            c.lock().unwrap().send(PacketUpdateImage {
+                image_name: &name,
+                grab_focus: false,
+                channel_names: &["R", "G", "B"],
+                channel_offsets: &[0, 1, 2],
+                channel_strides: &[0, 0, 0],
+                x: x as u32,
+                y: y_inv as u32,
+                width: 1,
+                height: 1,
+                data: &[pixel.x, pixel.y, pixel.z],
+            })
+        });
+    }
 
-pub fn set_pixel_grey(name: &str, x: usize, y: usize, grey: f32) {
+    pub fn set_pixel_grey(&self, name: &str, x: usize, y: usize, grey: f32) {
-    let mut debugger = DEBUGGER.lock().unwrap();
+        let mut images = self.images.lock().unwrap();
-    let (_it, img) = debugger
+        let (_it, img) = images
-        .images
+            .get_mut(name)
-        .get_mut(name)
+            .unwrap_or_else(|| panic!("couldn't find image named '{}'", name));
-        .expect(&format!("couldn't find image named '{}'", name));
+        let y_inv = img.h - y - 1;
-    let y_inv = img.h - y - 1;
+        img.put_pixel(x, y_inv, [grey, grey, grey].into());
-    img.put_pixel(x, y_inv, [grey, grey, grey].into());
+    }
+    pub fn write_images<P: AsRef<Path>>(
+        &self,
+        scene: &Scene,
+        render_time: time::Duration,
+        output_dir: P,
+    ) -> std::io::Result<()> {
+        let output_dir: &Path = output_dir.as_ref();
+        let now = Local::now();
+        let images = self.images.lock().unwrap();
+        // Write out images in consistent order.
+        let mut names = images.keys().collect::<Vec<_>>();
+        names.sort();
+        let mut image_metadata = Vec::new();
+        for name in &names {
+            let (it, img) = images.get(*name).unwrap();
+            let image = format!("{}.png", name);
+            let binary = format!("{}.json", name);
+            let ratio = img.w as f32 / img.h as f32;
+            let size = (img.w, img.h);
+            let image_path = output_dir.join(&image);
+            let binary_path = output_dir.join(&binary);
+            image_metadata.push(ImageMetadata {
+                name: name.to_string(),
+                image,
+                binary,
+                ratio,
+                size,
+                format: *it,
+            });
+            info!("Saving {}", image_path.to_string_lossy());
+            match it {
+                ImageType::RGB01 => {
+                    let mut out_img = image::RgbImage::new(img.w as u32, img.h as u32);
+                    out_img
+                        .enumerate_pixels_mut()
+                        .enumerate()
+                        .for_each(|(i, (_x, _y, p))| {
+                            let pixel = img.pix[i];
+                            *p = image::Rgb([
+                                (pixel[0] * 255.).min(255.) as u8,
+                                (pixel[1] * 255.).min(255.) as u8,
+                                (pixel[2] * 255.).min(255.) as u8,
+                            ])
+                        });
+                    out_img.save(image_path)?;
+                }
+                ImageType::Grey01 => {
+                    let mut out_img = image::GrayImage::new(img.w as u32, img.h as u32);
+                    out_img
+                        .enumerate_pixels_mut()
+                        .enumerate()
+                        .for_each(|(i, (_x, _y, p))| {
+                            let pixel = img.pix[i];
+                            *p = image::Luma([(pixel[0] * 255.).min(255.) as u8])
+                        });
+                    out_img.save(image_path)?;
+                }
+                ImageType::GreyNormalized => {
+                    let mut out_img = image::GrayImage::new(img.w as u32, img.h as u32);
+
+                    let max_val = img.pix.iter().map(|v| v.x).fold(0., f32::max);
+                    out_img
+                        .enumerate_pixels_mut()
+                        .enumerate()
+                        .for_each(|(i, (_x, _y, p))| {
+                            let pixel = img.pix[i];
+                            *p = image::Luma([(pixel[0] / max_val * 255.).min(255.) as u8])
+                        });
+                    out_img.save(image_path)?;
+                }
+            };
+            info!("Saving {}", binary_path.to_string_lossy());
+            let f = File::create(output_dir.join(binary_path))?;
+            let f = BufWriter::new(f);
+            match it {
+                ImageType::RGB01 => {
+                    serde_json::ser::to_writer(
+                        f,
+                        &img.pix
+                            .iter()
+                            .map(|v| [v.x, v.y, v.z])
+                            .collect::<Vec<[f32; 3]>>(),
+                    )?;
+                }
+                ImageType::Grey01 | ImageType::GreyNormalized => {
+                    serde_json::ser::to_writer(
+                        f,
+                        &img.pix.iter().map(|v| v.x).collect::<Vec<f32>>(),
+                    )?;
+                }
+            };
+        }
+        let f = File::create(output_dir.join("data.json"))?;
+        let f = BufWriter::new(f);
+        serde_json::ser::to_writer(
+            f,
+            &Data {
+                timestamp: now.timestamp(),
+                render_time_seconds: render_time.as_secs_f32(),
+                scene,
+                image_metadata,
+            },
+        )?;
+        Ok(())
+    }
 }
 
 trait ImageSaver {
@@ -118,105 +248,3 @@ trait ImageSaver {
     where
         Q: AsRef<Path> + Sized;
 }
-
-pub fn write_images<P: AsRef<Path>>(
-    scene: &Scene,
-    render_time: time::Duration,
-    output_dir: P,
-) -> std::io::Result<()> {
-    let output_dir: &Path = output_dir.as_ref();
-    let debugger = DEBUGGER.lock().unwrap();
-    let now = Local::now();
-    // Write out images in consistent order.
-    let mut names = debugger.images.keys().collect::<Vec<_>>();
-    names.sort();
-    let mut image_metadata = Vec::new();
-    for name in &names {
-        let (it, img) = debugger.images.get(*name).unwrap();
-        let image = format!("{}.png", name);
-        let binary = format!("{}.json", name);
-        let ratio = img.w as f32 / img.h as f32;
-        let size = (img.w, img.h);
-        let image_path = output_dir.join(&image);
-        let binary_path = output_dir.join(&binary);
-        image_metadata.push(ImageMetadata {
-            name: name.to_string(),
-            image,
-            binary,
-            ratio,
-            size,
-            format: *it,
-        });
-        info!("Saving {}", image_path.to_string_lossy());
-        match it {
-            ImageType::RGB01 => {
-                let mut out_img = image::RgbImage::new(img.w as u32, img.h as u32);
-                out_img
-                    .enumerate_pixels_mut()
-                    .enumerate()
-                    .for_each(|(i, (_x, _y, p))| {
-                        let pixel = img.pix[i];
-                        *p = image::Rgb([
-                            (pixel[0] * 255.).min(255.) as u8,
-                            (pixel[1] * 255.).min(255.) as u8,
-                            (pixel[2] * 255.).min(255.) as u8,
-                        ])
-                    });
-                out_img.save(image_path)?;
-            }
-            ImageType::Grey01 => {
-                let mut out_img = image::GrayImage::new(img.w as u32, img.h as u32);
-                out_img
-                    .enumerate_pixels_mut()
-                    .enumerate()
-                    .for_each(|(i, (_x, _y, p))| {
-                        let pixel = img.pix[i];
-                        *p = image::Luma([(pixel[0] * 255.).min(255.) as u8])
-                    });
-                out_img.save(image_path)?;
-            }
-            ImageType::GreyNormalized => {
-                let mut out_img = image::GrayImage::new(img.w as u32, img.h as u32);
-
-                let max_val = img.pix.iter().map(|v| v.x).fold(0., f32::max);
-                out_img
-                    .enumerate_pixels_mut()
-                    .enumerate()
-                    .for_each(|(i, (_x, _y, p))| {
-                        let pixel = img.pix[i];
-                        *p = image::Luma([(pixel[0] / max_val * 255.).min(255.) as u8])
-                    });
-                out_img.save(image_path)?;
-            }
-        };
-        info!("Saving {}", binary_path.to_string_lossy());
-        let f = File::create(output_dir.join(binary_path))?;
-        let f = BufWriter::new(f);
-        match it {
-            ImageType::RGB01 => {
-                serde_json::ser::to_writer(
-                    f,
-                    &img.pix
-                        .iter()
-                        .map(|v| [v.x, v.y, v.z])
-                        .collect::<Vec<[f32; 3]>>(),
-                )?;
-            }
-            ImageType::Grey01 | ImageType::GreyNormalized => {
-                serde_json::ser::to_writer(f, &img.pix.iter().map(|v| v.x).collect::<Vec<f32>>())?;
-            }
-        };
-    }
-    let f = File::create(output_dir.join("data.json"))?;
-    let f = BufWriter::new(f);
-    serde_json::ser::to_writer(
-        f,
-        &Data {
-            timestamp: now.timestamp(),
-            render_time_seconds: render_time.as_secs_f32(),
-            scene,
-            image_metadata,
-        },
-    )?;
-    Ok(())
-}

rtiow/renderer/src/parser.rs

@@ -0,0 +1,206 @@
+use crate::{
+    bvh_triangles::BVHTriangles,
+    camera::Camera,
+    cuboid::Cuboid,
+    hitable::Hit,
+    hitable_list::HitableList,
+    material::{Dielectric, DiffuseLight, Isotropic, Lambertian, Material, Metal},
+    renderer::Scene,
+    sphere::Sphere,
+    texture::{EnvMap, Texture},
+};
+use chrono::IsoWeek;
+use serde::Deserialize;
+use std::{collections::HashMap, fs::File, io::BufReader, path::PathBuf, sync::Arc};
+use stl::STL;
+use thiserror::Error;
+use vec3::Vec3;
+
+#[derive(Debug, Deserialize)]
+pub struct Config {
+    scene: SceneConfig,
+    camera: CameraConfig,
+    materials: Vec<MaterialConfig>,
+    hitables: Vec<HitableConfig>,
+    envmap: Option<EnvMapConfig>,
+}
+
+#[derive(Error, Debug)]
+pub enum ConfigError {
+    #[error("failed to load image")]
+    ImageError(#[from] image::ImageError),
+    #[error("failed to parser STL")]
+    STLError(#[from] stl::ParseError),
+    #[error("I/O error")]
+    IOError(#[from] std::io::Error),
+    #[error("duplication material named '{0}'")]
+    DuplicateMaterial(String),
+    #[error("unkown material named '{0}'")]
+    UnknownMaterial(String),
+}
+
+impl TryFrom<Config> for Scene {
+    type Error = ConfigError;
+
+    fn try_from(c: Config) -> Result<Scene, Self::Error> {
+        let mut materials = HashMap::new();
+        for mc in c.materials {
+            let v: Arc<dyn Material> = match mc.material {
+                Materials::Metal { albedo, fuzzy } => Arc::new(Metal::new(albedo, fuzzy)),
+                Materials::Dielectric { ref_idx } => Arc::new(Dielectric::new(ref_idx)),
+                Materials::DiffuseLight { texture } => Arc::new(DiffuseLight::new(texture)),
+                Materials::Isotropic { texture } => Arc::new(Isotropic::new(texture)),
+                Materials::Lambertian { texture } => Arc::new(Lambertian::new(texture)),
+            };
+            if materials.insert(mc.name.clone(), v).is_some() {
+                return Err(ConfigError::DuplicateMaterial(mc.name));
+            }
+        }
+
+        let hitables: Result<Vec<Box<dyn Hit>>, Self::Error> = c
+            .hitables
+            .into_iter()
+            .map(|hc| -> Result<Box<dyn Hit>, Self::Error> {
+                match hc.hitable {
+                    Hitables::Sphere { center, radius } => Ok(Box::new(Sphere::new(
+                        center,
+                        radius,
+                        Arc::clone(
+                            materials
+                                .get(&hc.material_name)
+                                .ok_or(ConfigError::UnknownMaterial(hc.material_name))?,
+                        ),
+                    ))),
+                    Hitables::Cuboid { min, max } => Ok(Box::new(Cuboid::new(
+                        min.into(),
+                        max.into(),
+                        Arc::clone(
+                            materials
+                                .get(&hc.material_name)
+                                .ok_or(ConfigError::UnknownMaterial(hc.material_name))?,
+                        ),
+                    ))),
+                    Hitables::STL { path, scale } => {
+                        let r = BufReader::new(File::open(path)?);
+                        let stl = STL::parse(r, false)?;
+                        Ok(Box::new(BVHTriangles::new(
+                            &stl,
+                            Arc::clone(
+                                materials
+                                    .get(&hc.material_name)
+                                    .ok_or(ConfigError::UnknownMaterial(hc.material_name))?,
+                            ),
+                            scale.unwrap_or(1.),
+                        )))
+                    }
+                }
+            })
+            .collect();
+        let hitables = hitables?;
+
+        let world: Box<dyn Hit> = Box::new(HitableList::new(hitables));
+        let mut env_map: Option<EnvMap> = None;
+
+        if let Some(em) = c.envmap {
+            let im = image::open(em.path)?.into_rgb();
+            env_map = Some(EnvMap::new(im));
+        };
+
+        let camera = make_camera(&c.camera, c.scene.width, c.scene.height);
+
+        let scene = Scene {
+            world,
+            camera,
+            env_map,
+            subsamples: c.scene.subsamples.unwrap_or(8),
+            adaptive_subsampling: c.scene.adaptive_subsampling,
+            num_threads: c.scene.num_threads,
+            width: c.scene.width,
+            height: c.scene.height,
+            global_illumination: c.scene.global_illumination.unwrap_or(true),
+        };
+        Ok(scene)
+    }
+}
+
+fn make_camera(cfg: &CameraConfig, width: usize, height: usize) -> Camera {
+    Camera::new(
+        cfg.lookfrom.into(),
+        cfg.lookat.into(),
+        Vec3::new(0., 1., 0.),
+        cfg.fov,
+        width as f32 / height as f32,
+        cfg.aperture,
+        cfg.focus_dist,
+        cfg.time_min,
+        cfg.time_max,
+    )
+}
+
+#[derive(Debug, Deserialize)]
+struct SceneConfig {
+    subsamples: Option<usize>,
+    adaptive_subsampling: Option<f32>,
+    num_threads: Option<usize>,
+    width: usize,
+    height: usize,
+    global_illumination: Option<bool>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type")]
+struct HitableConfig {
+    material_name: String,
+    #[serde(flatten)]
+    hitable: Hitables,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type")]
+enum Hitables {
+    #[serde(rename = "sphere")]
+    Sphere { center: [f32; 3], radius: f32 },
+    #[serde(rename = "cuboid")]
+    Cuboid { min: [f32; 3], max: [f32; 3] },
+    #[serde(rename = "stl")]
+    STL { path: PathBuf, scale: Option<f32> },
+}
+
+#[derive(Debug, Deserialize)]
+struct MaterialConfig {
+    name: String,
+    #[serde(flatten)]
+    material: Materials,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type")]
+enum Materials {
+    #[serde(rename = "metal")]
+    Metal { albedo: [f32; 3], fuzzy: f32 },
+    #[serde(rename = "dielectric")]
+    Dielectric { ref_idx: f32 },
+    // TODO(wathiede): these all take Textures, for now, only support RGB
+    #[serde(rename = "diffuse_light")]
+    DiffuseLight { texture: [f32; 3] },
+    #[serde(rename = "isotropic")]
+    Isotropic { texture: [f32; 3] },
+    #[serde(rename = "lambertian")]
+    Lambertian { texture: [f32; 3] },
+}
+
+#[derive(Debug, Deserialize)]
+pub struct CameraConfig {
+    lookfrom: [f32; 3],
+    lookat: [f32; 3],
+    fov: f32,
+    aperture: f32,
+    focus_dist: f32,
+    time_min: f32,
+    time_max: f32,
+}
+
+#[derive(Debug, Deserialize)]
+struct EnvMapConfig {
+    path: PathBuf,
+}

rtiow/renderer/src/ray.rs

@@ -5,6 +5,9 @@ pub struct Ray {
     pub origin: Vec3,
     pub direction: Vec3,
     pub time: f32,
+
+    // Precache 1/direction, a single ray intersects multiple AABB's, and divides are more
+    // expensive than multiplies.
     pub inv_direction: Vec3,
     pub sign: [usize; 3],
 }
@@ -14,7 +17,7 @@ impl Ray {
     where
         V: Into<Vec3>,
     {
-        let direction = direction.into();
+        let direction: Vec3 = direction.into();
         let origin = origin.into();
         let inv = 1. / direction;
         Ray {

rtiow/renderer/src/rect.rs

@@ -1,12 +1,14 @@
 // There are many math functions in this file, so we allow single letter variable names.
 #![allow(clippy::many_single_char_names)]
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::material::Material;
+    material::Material,
-use crate::ray::Ray;
+    ray::Ray,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
+#[derive(Debug)]
 pub struct XYRect<M>
 where
     M: Material,
@@ -68,6 +70,7 @@ where
     }
 }
 
+#[derive(Debug)]
 pub struct XZRect<M>
 where
     M: Material,
@@ -129,6 +132,7 @@ where
     }
 }
 
+#[derive(Debug)]
 pub struct YZRect<M>
 where
     M: Material,

rtiow/renderer/src/renderer.rs

@@ -1,40 +1,41 @@
-use std::fmt;
+use std::{
-use std::ops::AddAssign;
+    collections::HashMap,
-use std::ops::Range;
+    fmt,
-use std::path::Path;
+    ops::{AddAssign, Range},
-use std::path::PathBuf;
+    path::{Path, PathBuf},
-use std::str;
+    str, sync,
-use std::sync;
+    sync::{
-use std::sync::mpsc::sync_channel;
+        mpsc::{sync_channel, Receiver, SyncSender},
-use std::sync::mpsc::Receiver;
+        Arc, Mutex,
-use std::sync::mpsc::SyncSender;
+    },
-use std::sync::Arc;
+    thread,
-use std::sync::Mutex;
+    time::{Duration, Instant},
-use std::thread;
+};
-use std::time;
 
 use core_affinity;
-use log::info;
+use log::{info, trace};
-use log::trace;
 use num_cpus;
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 use serde_derive::Serialize;
 use structopt::StructOpt;
 
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::human;
+    hitable::Hit,
-use crate::material::Lambertian;
+    human,
-use crate::output;
+    material::{Lambertian, Material},
-use crate::ray::Ray;
+    output,
-use crate::scenes;
+    output::OutputManager,
-use crate::sphere::Sphere;
+    ray::Ray,
-use crate::texture::ConstantTexture;
+    scenes,
-use crate::texture::EnvMap;
+    sphere::Sphere,
-use crate::vec3::Vec3;
+    texture::{ConstantTexture, EnvMap},
+    vec3::Vec3,
+};
+use strum::{EnumString, EnumVariantNames};
 
-#[derive(Debug)]
+#[derive(Debug, EnumString, EnumVariantNames, strum::Display)]
+#[strum(serialize_all = "snake_case")]
 pub enum Model {
     BVH,
     Bench,
@@ -45,24 +46,30 @@ pub enum Model {
     Mandelbrot,
     PerlinDebug,
     Spheramid,
+    Stltest,
     Test,
+    Tron,
     Tutorial,
+    Dragon,
 }
 
 impl Model {
     pub fn scene(&self, opt: &Opt) -> Scene {
         match self {
-            Model::BVH => scenes::bvh::new(&opt),
+            Model::BVH => scenes::bvh::new(opt),
-            Model::Bench => scenes::bench::new(&opt),
+            Model::Bench => scenes::bench::new(opt),
-            Model::Book => scenes::book::new(&opt),
+            Model::Book => scenes::book::new(opt),
-            Model::CornellBox => scenes::cornell_box::new(&opt),
+            Model::CornellBox => scenes::cornell_box::new(opt),
-            Model::CornellSmoke => scenes::cornell_smoke::new(&opt),
+            Model::CornellSmoke => scenes::cornell_smoke::new(opt),
-            Model::Final => scenes::final_scene::new(&opt),
+            Model::Dragon => scenes::dragon::new(opt),
-            Model::Mandelbrot => scenes::mandelbrot::new(&opt),
+            Model::Final => scenes::final_scene::new(opt),
-            Model::PerlinDebug => scenes::perlin_debug::new(&opt),
+            Model::Mandelbrot => scenes::mandelbrot::new(opt),
-            Model::Spheramid => scenes::spheramid::new(&opt),
+            Model::PerlinDebug => scenes::perlin_debug::new(opt),
-            Model::Test => scenes::test::new(&opt),
+            Model::Spheramid => scenes::spheramid::new(opt),
-            Model::Tutorial => scenes::tutorial::new(&opt),
+            Model::Stltest => scenes::stltest::new(opt),
+            Model::Test => scenes::test::new(opt),
+            Model::Tron => scenes::tron::new(opt),
+            Model::Tutorial => scenes::tutorial::new(opt),
         }
     }
 }
@@ -76,44 +83,6 @@ impl fmt::Display for ModelParseError {
     }
 }
 
-impl str::FromStr for Model {
-    type Err = ModelParseError;
-    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
-        match s {
-            "bench" => Ok(Model::Bench),
-            "book" => Ok(Model::Book),
-            "bvh" => Ok(Model::BVH),
-            "cornell_box" => Ok(Model::CornellBox),
-            "cornell_smoke" => Ok(Model::CornellSmoke),
-            "final" => Ok(Model::Final),
-            "mandelbrot" => Ok(Model::Mandelbrot),
-            "perlin_debug" => Ok(Model::PerlinDebug),
-            "spheramid" => Ok(Model::Spheramid),
-            "test" => Ok(Model::Test),
-            "tutorial" => Ok(Model::Tutorial),
-            _ => Err(ModelParseError(s.to_owned())),
-        }
-    }
-}
-
-impl std::string::ToString for Model {
-    fn to_string(&self) -> String {
-        match self {
-            Model::BVH => "bvh".to_string(),
-            Model::Bench => "bench".to_string(),
-            Model::Book => "book".to_string(),
-            Model::CornellBox => "cornell_box".to_string(),
-            Model::CornellSmoke => "cornell_smoke".to_string(),
-            Model::Final => "final".to_string(),
-            Model::Mandelbrot => "mandelbrot".to_string(),
-            Model::PerlinDebug => "perlin_debug".to_string(),
-            Model::Spheramid => "spheramid".to_string(),
-            Model::Test => "test".to_string(),
-            Model::Tutorial => "tutorial".to_string(),
-        }
-    }
-}
-
 #[derive(Debug, StructOpt)]
 #[structopt(name = "tracer", about = "An experimental ray tracer.")]
 pub struct Opt {
@@ -129,19 +98,29 @@ pub struct Opt {
     /// Sub-samples per pixel
     #[structopt(short = "s", long = "subsample", default_value = "8")]
     pub subsamples: usize,
-    /// Select scene to render, one of: "bench", "book", "tutorial", "bvh", "test", "cornell_box",
+    /// Select scene to render.
-    /// "cornell_smoke", "perlin_debug", "final"
+    #[structopt(long = "model")]
-    #[structopt(long = "model", default_value = "book")]
+    pub model: Option<Model>,
-    pub model: Model,
+    /// Toml config describing scene.
+    #[structopt(long = "config")]
+    pub config: Option<PathBuf>,
     /// Path to store pprof profile data, i.e. /tmp/cpuprofile.pprof
     #[structopt(long = "pprof", parse(from_os_str))]
     pub pprof: Option<PathBuf>,
     /// Use acceleration data structure, may be BVH or kd-tree depending on scene.
     #[structopt(long = "use_accel")]
     pub use_accel: bool,
+    /// Host:port of running tev instance.
+    #[structopt(long = "tev_addr")]
+    pub tev_addr: Option<String>,
 
     /// Output directory
-    #[structopt(parse(from_os_str), default_value = "/tmp/tracer")]
+    #[structopt(
+        short = "o",
+        long = "output",
+        parse(from_os_str),
+        default_value = "/tmp/tracer"
+    )]
     pub output: PathBuf,
 }
 
@@ -153,18 +132,20 @@ pub fn opt_hash(opt: &Opt) -> String {
         opt.height,
         opt.subsamples,
         opt.pprof.is_some(),
-        opt.model.to_string(),
+        opt.model.as_ref().unwrap().to_string(),
         opt.use_accel,
-        opt.output.display().to_string().replace("/", "_")
+        opt.output.display().to_string().replace('/', "_")
     )
 }
 
 // TODO(wathiede): implement the skips and then the renderer could use json as an input file type.
-#[derive(Serialize)]
+#[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Scene {
     #[serde(skip)]
     pub world: Box<dyn Hit>,
+    //#[serde(skip)]
+    //pub materials: HashMap<String, Box<dyn Material>>,
     #[serde(skip)]
     pub camera: Camera,
     pub subsamples: usize,
@@ -269,6 +250,7 @@ fn trace_pixel_adaptive(
     x_range: Range<f32>,
     y_range: Range<f32>,
     scene: &Scene,
+    output: &OutputManager,
 ) -> (Vec3, usize) {
     let w = scene.width as f32;
     let h = scene.height as f32;
@@ -283,7 +265,7 @@ fn trace_pixel_adaptive(
         &scene.env_map,
     );
     if depth == 0 {
-        output::set_pixel(output::ADAPTIVE_DEPTH, x, y, [1., 0., 0.].into());
+        output.set_pixel(output::ADAPTIVE_DEPTH, x, y, [1., 0., 0.].into());
         return (center, rays);
     }
     // t = top
@@ -325,6 +307,7 @@ fn trace_pixel_adaptive(
             x_range.start..x_mid,
             y_range.start..y_mid,
             scene,
+            output,
         );
         let tr = trace_pixel_adaptive(
             depth - 1,
@@ -334,6 +317,7 @@ fn trace_pixel_adaptive(
             x_mid..x_range.end,
             y_range.start..y_mid,
             scene,
+            output,
         );
         let bl = trace_pixel_adaptive(
             depth - 1,
@@ -343,6 +327,7 @@ fn trace_pixel_adaptive(
             x_range.start..x_mid,
             y_mid..y_range.end,
             scene,
+            output,
         );
         let br = trace_pixel_adaptive(
             depth - 1,
@@ -352,13 +337,14 @@ fn trace_pixel_adaptive(
             x_mid..x_range.end,
             y_mid..y_range.end,
             scene,
+            output,
         );
         let pixel = (tl.0 + tr.0 + bl.0 + br.0) / 4.;
         let rays = tl.1 + tr.1 + bl.1 + br.1;
         (pixel, rays)
     } else {
         if depth == MAX_ADAPTIVE_DEPTH {
-            output::set_pixel(output::ADAPTIVE_DEPTH, x, y, [0., 1., 0.].into());
+            output.set_pixel(output::ADAPTIVE_DEPTH, x, y, [0., 1., 0.].into());
         }
         (corners, rays)
     }
@@ -378,7 +364,7 @@ fn trace_pixel_random(x: usize, y: usize, scene: &Scene) -> (Vec3, usize) {
     )
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Default)]
 struct RenderStats {
     rays: usize,
     pixels: usize,
@@ -394,33 +380,37 @@ impl AddAssign for RenderStats {
 }
 
 fn progress(
+    start_time: Instant,
     last_stat: &RenderStats,
     current_stat: &RenderStats,
-    time_diff: time::Duration,
+    time_diff: Duration,
     pixel_total: usize,
 ) -> String {
     let human = human::Formatter::new();
     let pixel_diff = current_stat.pixels - last_stat.pixels;
     let ray_diff = current_stat.rays - last_stat.rays;
+    let now = Instant::now();
+    let start_diff = now - start_time;
+    let ratio = current_stat.pixels as f32 / pixel_total as f32;
+    let percent = ratio * 100.;
+    let elapsed = start_diff.as_secs_f32();
+    let total = elapsed * (1. / ratio);
+    let eta = total - elapsed;
     format!(
-        "{:7} / {:7}pixels ({:2}%) {:7}pixels/s {:7}rays/s",
+        "{:7} / {:7}pixels ({:2.0}%) {:7}pixels/s {:7}rays/s eta {:.0}s",
         human.format(current_stat.pixels as f64),
         human.format(pixel_total as f64),
-        100 * current_stat.pixels / pixel_total,
+        percent,
         human.format(pixel_diff as f64 / time_diff.as_secs_f64()),
-        human.format(ray_diff as f64 / time_diff.as_secs_f64())
+        human.format(ray_diff as f64 / time_diff.as_secs_f64()),
+        eta
     )
 }
 
-impl Default for RenderStats {
-    fn default() -> Self {
-        RenderStats { rays: 0, pixels: 0 }
-    }
-}
-
 enum Request {
     Pixel { x: usize, y: usize },
     Line { width: usize, y: usize },
+    // TODO(wathiede): add Cohort that does 4x4 or 8x8 pixel chunks.
 }
 
 enum Response {
@@ -437,7 +427,7 @@ enum Response {
     },
 }
 
-fn render_pixel(scene: &Scene, x: usize, y: usize) -> (Vec3, usize) {
+fn render_pixel(scene: &Scene, x: usize, y: usize, output: &OutputManager) -> (Vec3, usize) {
     let (pixel, rays) = if let Some(threshold) = scene.adaptive_subsampling {
         trace_pixel_adaptive(
             MAX_ADAPTIVE_DEPTH,
@@ -447,6 +437,7 @@ fn render_pixel(scene: &Scene, x: usize, y: usize) -> (Vec3, usize) {
             0.0..1.0,
             0.0..1.0,
             scene,
+            output,
         )
     } else {
         let (pixel, rays) = (0..scene.subsamples)
@@ -455,7 +446,7 @@ fn render_pixel(scene: &Scene, x: usize, y: usize) -> (Vec3, usize) {
                 ([0., 0., 0.].into(), 0),
                 |(p1, r1): (Vec3, usize), (p2, r2): (Vec3, usize)| ((p1 + p2), (r1 + r2)),
             );
-        output::set_pixel_grey(output::RAYS_PER_PIXEL, x, y, rays as f32);
+        output.set_pixel_grey(output::RAYS_PER_PIXEL, x, y, rays as f32);
         (pixel / scene.subsamples as f32, rays)
     };
     // Gamma correct, use gamma 2 correction, which is 1/gamma where gamma=2 which is 1/2 or
@@ -471,6 +462,7 @@ fn render_worker(
     scene: &Scene,
     input_chan: Arc<Mutex<Receiver<Request>>>,
     output_chan: &SyncSender<Response>,
+    output: &OutputManager,
 ) {
     loop {
         let job = { input_chan.lock().unwrap().recv() };
@@ -485,7 +477,7 @@ fn render_worker(
                     let batch = false;
                     if batch {
                         let (pixels, rays): (Vec<Vec3>, Vec<usize>) = (0..width)
-                            .map(|x| render_pixel(scene, x, y))
+                            .map(|x| render_pixel(scene, x, y, output))
                             .collect::<Vec<(_, _)>>()
                             .into_iter()
                             .unzip();
@@ -502,7 +494,7 @@ fn render_worker(
                             .expect("failed to send pixel response");
                     } else {
                         (0..width).for_each(|x| {
-                            let (pixel, rays) = render_pixel(scene, x, y);
+                            let (pixel, rays) = render_pixel(scene, x, y, output);
                             output_chan
                                 .send(Response::Pixel {
                                     x,
@@ -516,7 +508,7 @@ fn render_worker(
                 }
                 Request::Pixel { x, y } => {
                     trace!("tid {} x {} y {}", tid, x, y);
-                    let (pixel, rays) = render_pixel(scene, x, y);
+                    let (pixel, rays) = render_pixel(scene, x, y, output);
                     output_chan
                         .send(Response::Pixel {
                             x,
@@ -531,8 +523,19 @@ fn render_worker(
     }
 }
 
-pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::io::Error> {
+/*
-    let num_threads = scene.num_threads.unwrap_or_else(num_cpus::get);
+lazy_static! {
+    static ref DEBUGGER: Arc<Mutex<OutputManager>> = Arc::new(Mutex::new(OutputManager::new()));
+}
+*/
+
+pub fn render(
+    scene: Scene,
+    output_dir: &Path,
+    tev_addr: &Option<String>,
+) -> std::result::Result<(), std::io::Error> {
+    // Default to half the cores to disable hyperthreading.
+    let num_threads = scene.num_threads.unwrap_or_else(|| num_cpus::get() / 2);
     let (pixel_req_tx, pixel_req_rx) = sync_channel(2 * num_threads);
     let (pixel_resp_tx, pixel_resp_rx) = sync_channel(2 * num_threads);
 
@@ -546,20 +549,23 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
     } else {
         core_ids
     };
+    let output = output::OutputManager::new(tev_addr)?;
+    let output = Arc::new(output);
+
     info!("Creating {} render threads", core_ids.len());
-    output::register_image(
+    output.register_image(
         output::MAIN_IMAGE.to_string(),
         (scene.width, scene.height),
         output::ImageType::RGB01,
     );
     if scene.adaptive_subsampling.is_some() {
-        output::register_image(
+        output.register_image(
             output::ADAPTIVE_DEPTH.to_string(),
             (scene.width, scene.height),
             output::ImageType::RGB01,
         );
     }
-    output::register_image(
+    output.register_image(
         output::RAYS_PER_PIXEL.to_string(),
         (scene.width, scene.height),
         output::ImageType::GreyNormalized,
@@ -573,19 +579,19 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
             let s = sync::Arc::clone(&scene);
             let pixel_req_rx = pixel_req_rx.clone();
             let pixel_resp_tx = pixel_resp_tx.clone();
+            let output = sync::Arc::clone(&output);
             thread::spawn(move || {
                 core_affinity::set_for_current(id);
-                render_worker(i, &s, pixel_req_rx, &pixel_resp_tx);
+                render_worker(i, &s, pixel_req_rx, &pixel_resp_tx, &output);
             })
         })
         .collect::<Vec<_>>();
     drop(pixel_req_rx);
     drop(pixel_resp_tx);
 
-    let start_time = time::Instant::now();
     let (w, h) = (scene.width, scene.height);
     handles.push(thread::spawn(move || {
-        let batch_line_requests = true;
+        let batch_line_requests = false;
         if batch_line_requests {
             for y in 0..h {
                 pixel_req_tx
@@ -607,29 +613,36 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
     info!("Rendering with {} subsamples", scene.subsamples);
 
     let pixel_total = scene.width * scene.height;
-    let mut last_time = time::Instant::now();
+    let mut last_time = Instant::now();
     let mut last_stat: RenderStats = Default::default();
     let mut current_stat: RenderStats = Default::default();
+    let render_start_time = Instant::now();
     for resp in pixel_resp_rx {
         match resp {
             Response::Pixel { x, y, pixel, rs } => {
                 current_stat += rs;
-                output::set_pixel(output::MAIN_IMAGE, x, y, pixel);
+                output.set_pixel(output::MAIN_IMAGE, x, y, pixel);
             }
             Response::Line { y, pixels, rs } => {
                 current_stat += rs;
                 for (x, pixel) in pixels.iter().enumerate() {
-                    output::set_pixel(output::MAIN_IMAGE, x, y, *pixel);
+                    output.set_pixel(output::MAIN_IMAGE, x, y, *pixel);
                 }
             }
         }
 
-        let now = time::Instant::now();
+        let now = Instant::now();
         let time_diff = now - last_time;
-        if time_diff > time::Duration::from_secs(1) {
+        if time_diff > Duration::from_secs(5) {
-            info!(
+            println!(
                 "{}",
-                progress(&last_stat, &current_stat, time_diff, pixel_total)
+                progress(
+                    render_start_time,
+                    &last_stat,
+                    &current_stat,
+                    time_diff,
+                    pixel_total
+                )
             );
             last_stat = current_stat;
             last_time = now;
@@ -638,12 +651,18 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
     for thr in handles {
         thr.join().expect("thread join");
     }
-    let time_diff = time::Instant::now() - start_time;
+    let time_diff = Instant::now() - render_start_time;
-    info!(
+    println!(
-        "Runtime {} seconds {}",
+        "Render {} seconds {}",
         time_diff.as_secs_f32(),
-        progress(&Default::default(), &current_stat, time_diff, pixel_total)
+        progress(
+            render_start_time,
+            &Default::default(),
+            &current_stat,
+            time_diff,
+            pixel_total
+        )
     );
 
-    output::write_images(&scene, time_diff, output_dir)
+    output.write_images(&scene, time_diff, output_dir)
 }

rtiow/renderer/src/rotate.rs

@@ -1,13 +1,13 @@
-use std::f32::consts::PI;
+use std::f32::{consts::PI, MAX, MIN};
-use std::f32::MAX;
-use std::f32::MIN;
 
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::ray::Ray;
+    ray::Ray,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
+#[derive(Debug)]
 pub struct RotateY<H>
 where
     H: Hit,

rtiow/renderer/src/scale.rs

@@ -0,0 +1,47 @@
+use crate::{
+    aabb::AABB,
+    hitable::{Hit, HitRecord},
+    ray::Ray,
+};
+
+#[derive(Debug)]
+pub struct Scale<H>
+where
+    H: Hit,
+{
+    hitable: H,
+    scale: f32,
+}
+
+impl<H> Scale<H>
+where
+    H: Hit,
+{
+    pub fn new(hitable: H, scale: f32) -> Scale<H> {
+        Scale { hitable, scale }
+    }
+}
+
+impl<H> Hit for Scale<H>
+where
+    H: Hit,
+{
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        let moved_r = Ray::new(r.origin / self.scale, r.direction, r.time);
+        if let Some(rec) = self.hitable.hit(moved_r, t_min, t_max) {
+            return Some(HitRecord {
+                p: rec.p * self.scale,
+                t: rec.t * self.scale,
+                ..rec
+            });
+        }
+        None
+    }
+
+    fn bounding_box(&self, t_min: f32, t_max: f32) -> Option<AABB> {
+        if let Some(bbox) = self.hitable.bounding_box(t_min, t_max) {
+            return Some(AABB::new(bbox.min() * self.scale, bbox.max() * self.scale));
+        }
+        None
+    }
+}

rtiow/renderer/src/scenes/bench.rs

@@ -1,18 +1,18 @@
 use log::trace;
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::bvh::BVH;
+use crate::{
-use crate::camera::Camera;
+    bvh::BVH,
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::Lambertian;
+    kdtree::KDTree,
-use crate::renderer::Opt;
+    material::Lambertian,
-use crate::renderer::Scene;
+    renderer::{Opt, Scene},
-use crate::sphere::Sphere;
+    sphere::Sphere,
-use crate::texture::ConstantTexture;
+    texture::ConstantTexture,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(20., 20., 20.);

rtiow/renderer/src/scenes/book.rs

@@ -1,21 +1,16 @@
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::Dielectric;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{Dielectric, Lambertian, Material, Metal},
-use crate::material::Material;
+    renderer::{Opt, Scene},
-use crate::material::Metal;
+    sphere::Sphere,
-use crate::renderer::Opt;
+    texture::{CheckerTexture, ConstantTexture, EnvMap},
-use crate::renderer::Scene;
+    vec3::Vec3,
-use crate::sphere::Sphere;
+};
-use crate::texture::CheckerTexture;
-use crate::texture::ConstantTexture;
-use crate::texture::EnvMap;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(13., 2., 3.);

rtiow/renderer/src/scenes/bvh.rs

@@ -1,16 +1,16 @@
 use log::trace;
 
-use crate::bvh::BVH;
+use crate::{
-use crate::camera::Camera;
+    bvh::BVH,
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::material::Lambertian;
+    hitable::Hit,
-use crate::material::Metal;
+    material::{Lambertian, Metal},
-use crate::moving_sphere::MovingSphere;
+    moving_sphere::MovingSphere,
-use crate::renderer::Opt;
+    renderer::{Opt, Scene},
-use crate::renderer::Scene;
+    sphere::Sphere,
-use crate::sphere::Sphere;
+    texture::ConstantTexture,
-use crate::texture::ConstantTexture;
+    vec3::Vec3,
-use crate::vec3::Vec3;
+};
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(3., 3., 2.);

rtiow/renderer/src/scenes/cornell_box.rs

@@ -1,22 +1,20 @@
 use std::sync::Arc;
 
-use crate::camera::Camera;
+use crate::{
-use crate::cuboid::Cuboid;
+    camera::Camera,
-use crate::flip_normals::FlipNormals;
+    cuboid::Cuboid,
-use crate::hitable::Hit;
+    flip_normals::FlipNormals,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::DiffuseLight;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{DiffuseLight, Lambertian},
-use crate::rect::XYRect;
+    rect::{XYRect, XZRect, YZRect},
-use crate::rect::XZRect;
+    renderer::{Opt, Scene},
-use crate::rect::YZRect;
+    rotate::RotateY,
-use crate::renderer::Opt;
+    texture::ConstantTexture,
-use crate::renderer::Scene;
+    translate::Translate,
-use crate::rotate::RotateY;
+    vec3::Vec3,
-use crate::texture::ConstantTexture;
+};
-use crate::translate::Translate;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(278., 278., -800.);

rtiow/renderer/src/scenes/cornell_smoke.rs

@@ -1,24 +1,21 @@
 use std::sync::Arc;
 
-use crate::camera::Camera;
+use crate::{
-use crate::constant_medium::ConstantMedium;
+    camera::Camera,
-use crate::cuboid::Cuboid;
+    constant_medium::ConstantMedium,
-use crate::flip_normals::FlipNormals;
+    cuboid::Cuboid,
-use crate::hitable::Hit;
+    flip_normals::FlipNormals,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::DiffuseLight;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{DiffuseLight, Lambertian, Material},
-use crate::material::Material;
+    rect::{XYRect, XZRect, YZRect},
-use crate::rect::XYRect;
+    renderer::{Opt, Scene},
-use crate::rect::XZRect;
+    rotate::RotateY,
-use crate::rect::YZRect;
+    texture::ConstantTexture,
-use crate::renderer::Opt;
+    translate::Translate,
-use crate::renderer::Scene;
+    vec3::Vec3,
-use crate::rotate::RotateY;
+};
-use crate::texture::ConstantTexture;
-use crate::translate::Translate;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(278., 278., -800.);

rtiow/renderer/src/scenes/dragon.rs

@@ -0,0 +1,116 @@
+use std::{
+    f32::consts::PI,
+    io::{BufReader, Cursor},
+};
+
+use stl::STL;
+
+use crate::{
+    bvh_triangles::BVHTriangles,
+    camera::Camera,
+    colors::generate_rainbow,
+    hitable::Hit,
+    hitable_list::HitableList,
+    kdtree::KDTree,
+    material::{Lambertian, Metal},
+    renderer::{Opt, Scene},
+    rotate::RotateY,
+    scale::Scale,
+    sphere::Sphere,
+    texture::{ConstantTexture, EnvMap},
+    translate::Translate,
+    vec3::Vec3,
+};
+
+pub fn new(opt: &Opt) -> Scene {
+    let lookfrom = Vec3::new(0., 80., 80.);
+    let lookat = Vec3::new(0., 0., 0.);
+    let dist_to_focus = 10.0;
+    let aperture = 0.0;
+    let time_min = 0.;
+    let time_max = 1.;
+    let camera = Camera::new(
+        lookfrom,
+        lookat,
+        Vec3::new(0., 1., 0.),
+        45.,
+        opt.width as f32 / opt.height as f32,
+        aperture,
+        dist_to_focus,
+        time_min,
+        time_max,
+    );
+    //let dragon_material = Dielectric::new(1.5);
+    let dragon_material = Metal::new(Vec3::new(0.6, 0.6, 0.6), 0.0);
+    //let dragon_material = Lambertian::new(ConstantTexture::new(Vec3::new(1.0, 1.0, 0.2)));
+
+    let ground_color = if opt.use_accel {
+        ConstantTexture::new(Vec3::new(1.0, 0.4, 0.4))
+    } else {
+        ConstantTexture::new(Vec3::new(0.4, 0.4, 0.4))
+    };
+
+    let stl_cube = STL::parse(
+        BufReader::new(Cursor::new(include_bytes!("../../stls/dragon.stl"))),
+        false,
+    )
+    .expect("failed to parse cube");
+    let _light_size = 50.;
+    let _light_height = 200.;
+    let sphere_radius = 5.;
+    let circle_radius = 40.;
+    let num_spheres = 16;
+    let palette = generate_rainbow(num_spheres);
+    let spheres: Vec<Box<dyn Hit>> = (0..num_spheres)
+        .map(|i| (i, i as f32, num_spheres as f32))
+        .map(|(idx, idx_f, n)| (idx, idx_f * 2. * PI / n))
+        .map(|(idx, rad)| -> Box<dyn Hit> {
+            let x = circle_radius * rad.cos();
+            let y = 4. * sphere_radius;
+            let z = circle_radius * rad.sin();
+            let c = palette[idx];
+            Box::new(Sphere::new(
+                [x, y, z],
+                sphere_radius,
+                Lambertian::new(ConstantTexture::new(c)),
+            ))
+        })
+        .collect();
+    let mut objects: Vec<Box<dyn Hit>> = vec![
+        Box::new(Sphere::new(
+            Vec3::new(0., 0.1, -0.5),
+            0.1,
+            Lambertian::new([0., 1., 1.]),
+        )),
+        // Earth sized sphere
+        //Box::new(Sphere::new( Vec3::new(0., -10000., 0.), 10000., Lambertian::new(ground_color),)),
+        // STL Mesh
+        Box::new(crate::debug_hit::DebugHit::new(RotateY::new(
+            Translate::new(
+                BVHTriangles::new(&stl_cube, dragon_material, 250.),
+                [0., -10., 0.],
+            ),
+            180.,
+        ))),
+    ];
+    objects.extend(spheres);
+
+    let world: Box<dyn Hit> = if opt.use_accel {
+        Box::new(KDTree::new(objects, time_min, time_max))
+    } else {
+        Box::new(HitableList::new(objects))
+    };
+    let skybox_bytes = include_bytes!("../../images/envmap.jpg");
+    let skybox = image::load_from_memory(skybox_bytes).unwrap().to_rgb();
+    Scene {
+        camera,
+        world,
+        subsamples: opt.subsamples,
+        num_threads: opt.num_threads,
+        width: opt.width,
+        height: opt.height,
+        global_illumination: true,
+        env_map: Some(EnvMap::new(skybox)),
+        ..Default::default()
+    }
+}

rtiow/renderer/src/scenes/final_scene.rs

@@ -1,33 +1,26 @@
 use std::sync::Arc;
 
 use image;
-use rand;
+use rand::{self, Rng};
-use rand::Rng;
 
-use crate::camera::Camera;
+use crate::{
-use crate::constant_medium::ConstantMedium;
+    camera::Camera,
-use crate::cuboid::Cuboid;
+    constant_medium::ConstantMedium,
-use crate::hitable::Hit;
+    cuboid::Cuboid,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::Dielectric;
+    kdtree::KDTree,
-use crate::material::DiffuseLight;
+    material::{Dielectric, DiffuseLight, Lambertian, Material, Metal},
-use crate::material::Lambertian;
+    moving_sphere::MovingSphere,
-use crate::material::Material;
+    noise::{perlin::Perlin, NoiseType},
-use crate::material::Metal;
+    rect::XZRect,
-use crate::moving_sphere::MovingSphere;
+    renderer::{Opt, Scene},
-use crate::noise::perlin::Perlin;
+    rotate::RotateY,
-use crate::noise::NoiseType;
+    sphere::Sphere,
-use crate::rect::XZRect;
+    texture::{ConstantTexture, ImageTexture, NoiseTexture},
-use crate::renderer::Opt;
+    translate::Translate,
-use crate::renderer::Scene;
+    vec3::Vec3,
-use crate::rotate::RotateY;
+};
-use crate::sphere::Sphere;
-use crate::texture::ConstantTexture;
-use crate::texture::ImageTexture;
-use crate::texture::NoiseTexture;
-use crate::translate::Translate;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(478., 278., -600.);

rtiow/renderer/src/scenes/mandelbrot.rs

@@ -1,24 +1,18 @@
 use rand;
 
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::DiffuseLight;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{DiffuseLight, Lambertian},
-use crate::noise::perlin::Perlin;
+    noise::{perlin::Perlin, NoiseType},
-use crate::noise::NoiseType;
+    rect::{XYRect, XZRect, YZRect},
-use crate::rect::XYRect;
+    renderer::{Opt, Scene},
-use crate::rect::XZRect;
+    sphere::Sphere,
-use crate::rect::YZRect;
+    texture::{ConstantTexture, ImageTexture, Mandelbrot, NoiseTexture},
-use crate::renderer::Opt;
+    vec3::Vec3,
-use crate::renderer::Scene;
+};
-use crate::sphere::Sphere;
-use crate::texture::ConstantTexture;
-use crate::texture::ImageTexture;
-use crate::texture::Mandelbrot;
-use crate::texture::NoiseTexture;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(20., 20., 20.);

rtiow/renderer/src/scenes/mod.rs

@@ -3,9 +3,12 @@ pub mod book;
 pub mod bvh;
 pub mod cornell_box;
 pub mod cornell_smoke;
+pub mod dragon;
 pub mod final_scene;
 pub mod mandelbrot;
 pub mod perlin_debug;
 pub mod spheramid;
+pub mod stltest;
 pub mod test;
+pub mod tron;
 pub mod tutorial;

rtiow/renderer/src/scenes/perlin_debug.rs

@@ -2,19 +2,18 @@ use std::sync::Arc;
 
 use rand;
 
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::Lambertian;
+    kdtree::KDTree,
-use crate::noise::perlin::Perlin;
+    material::Lambertian,
-use crate::noise::NoiseType;
+    noise::{perlin::Perlin, NoiseType},
-use crate::renderer::Opt;
+    renderer::{Opt, Scene},
-use crate::renderer::Scene;
+    sphere::Sphere,
-use crate::sphere::Sphere;
+    texture::{NoiseTexture, Texture},
-use crate::texture::NoiseTexture;
+    vec3::Vec3,
-use crate::texture::Texture;
+};
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(13., 2., 3.);

rtiow/renderer/src/scenes/spheramid.rs

@@ -1,18 +1,15 @@
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::material::Dielectric;
+    hitable_list::HitableList,
-use crate::material::Lambertian;
+    material::{Dielectric, Lambertian, Metal},
-use crate::material::Metal;
+    moving_sphere::MovingSphere,
-use crate::moving_sphere::MovingSphere;
+    rect::XYRect,
-use crate::rect::XYRect;
+    renderer::{Opt, Scene},
-use crate::renderer::Opt;
+    sphere::Sphere,
-use crate::renderer::Scene;
+    texture::{CheckerTexture, ConstantTexture, EnvMap},
-use crate::sphere::Sphere;
+    vec3::Vec3,
-use crate::texture::CheckerTexture;
+};
-use crate::texture::ConstantTexture;
-use crate::texture::EnvMap;
-use crate::vec3::Vec3;
 
 // Draws many spheres along each positive axis.
 // Blue X-positive

rtiow/renderer/src/scenes/stltest.rs

@@ -0,0 +1,122 @@
+use std::{
+    io::{BufReader, Cursor},
+    sync::Arc,
+};
+
+use stl::STL;
+
+use crate::{
+    bvh_triangles::BVHTriangles,
+    camera::Camera,
+    cuboid::Cuboid,
+    hitable::Hit,
+    hitable_list::HitableList,
+    kdtree::KDTree,
+    material::{Dielectric, Lambertian, Metal},
+    renderer::{Opt, Scene},
+    sphere::Sphere,
+    texture::{ConstantTexture, EnvMap},
+    translate::Translate,
+    vec3::Vec3,
+};
+
+pub fn new(opt: &Opt) -> Scene {
+    let lookfrom = Vec3::new(0., 40., -100.);
+    let lookat = Vec3::new(0., 10., 0.);
+    let dist_to_focus = 10.0;
+    let aperture = 0.0;
+    let time_min = 0.;
+    let time_max = 1.;
+    let camera = Camera::new(
+        lookfrom,
+        lookat,
+        Vec3::new(0., 1., 0.),
+        45.,
+        opt.width as f32 / opt.height as f32,
+        aperture,
+        dist_to_focus,
+        time_min,
+        time_max,
+    );
+    let ground_color = if opt.use_accel {
+        ConstantTexture::new(Vec3::new(1.0, 0.4, 0.4))
+    } else {
+        ConstantTexture::new(Vec3::new(0.4, 0.4, 0.4))
+    };
+
+    let glass = Dielectric::new(1.5);
+    let metal = Metal::new(Vec3::new(0.8, 0.8, 0.8), 0.2);
+    let red = Lambertian::new(ConstantTexture::new(Vec3::new(1.0, 0.2, 0.2)));
+
+    //let box_material = glass;
+    let _ = glass;
+    let _ = metal;
+    let _ = red;
+
+    let stl_cube = STL::parse(
+        BufReader::new(Cursor::new(include_bytes!("../../stls/cube.stl"))),
+        false,
+    )
+    .expect("failed to parse cube");
+    let objects: Vec<Box<dyn Hit>> = vec![
+        // Light from above - white
+        // Earth sized sphere
+        Box::new(Sphere::new(
+            Vec3::new(0., -10000., 0.),
+            10000.,
+            Lambertian::new(ground_color),
+        )),
+        Box::new(Sphere::new(
+            Vec3::new(0., 20., -40.),
+            10.,
+            Lambertian::new(ConstantTexture::new(Vec3::new(1., 0.2, 1.))),
+        )),
+        // Blue sphere
+        Box::new(Sphere::new(
+            Vec3::new(0., 20., 40.),
+            20.,
+            Lambertian::new(ConstantTexture::new(Vec3::new(0.2, 0.2, 1.))),
+        )),
+        Box::new(Sphere::new(
+            Vec3::new(40., 20., 40.),
+            20.,
+            //Metal::new(Vec3::new(0.8, 0.8, 0.8), 0.2),
+            Lambertian::new(ConstantTexture::new(Vec3::new(0.2, 1.0, 0.2))),
+        )),
+        Box::new(Sphere::new(
+            Vec3::new(-40., 20., 40.),
+            20.,
+            //Metal::new(Vec3::new(0.8, 0.8, 0.8), 0.2),
+            Lambertian::new(ConstantTexture::new(Vec3::new(1.0, 0.2, 0.2))),
+        )),
+        // STL Mesh
+        Box::new(Translate::new(
+            BVHTriangles::new(&stl_cube, glass, 1.),
+            [0., 10., 0.],
+        )),
+        //Box::new(BVHTriangles::new(&stl_cube, box_material.clone())),
+        Box::new(Cuboid::new(
+            [-20., 0., 0.].into(),
+            [0., 20., 20.].into(),
+            Arc::new(red),
+        )),
+    ];
+    let world: Box<dyn Hit> = if opt.use_accel {
+        Box::new(KDTree::new(objects, time_min, time_max))
+    } else {
+        Box::new(HitableList::new(objects))
+    };
+    let skybox_bytes = include_bytes!("../../images/envmap.jpg");
+    let skybox = image::load_from_memory(skybox_bytes).unwrap().to_rgb();
+    Scene {
+        camera,
+        world,
+        subsamples: opt.subsamples,
+        num_threads: opt.num_threads,
+        width: opt.width,
+        height: opt.height,
+        global_illumination: true,
+        env_map: Some(EnvMap::new(skybox)),
+        ..Default::default()
+    }
+}

rtiow/renderer/src/scenes/test.rs

@@ -1,24 +1,19 @@
 use image;
 use rand;
 
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::DiffuseLight;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{DiffuseLight, Lambertian},
-use crate::noise::perlin::Perlin;
+    noise::{perlin::Perlin, NoiseType},
-use crate::noise::NoiseType;
+    rect::{XYRect, XZRect, YZRect},
-use crate::rect::XYRect;
+    renderer::{Opt, Scene},
-use crate::rect::XZRect;
+    sphere::Sphere,
-use crate::rect::YZRect;
+    texture::{ConstantTexture, ImageTexture, NoiseTexture},
-use crate::renderer::Opt;
+    vec3::Vec3,
-use crate::renderer::Scene;
+};
-use crate::sphere::Sphere;
-use crate::texture::ConstantTexture;
-use crate::texture::ImageTexture;
-use crate::texture::NoiseTexture;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(20., 20., 20.);

rtiow/renderer/src/scenes/tron.rs

@@ -0,0 +1,124 @@
+use std::sync::Arc;
+
+use log::info;
+
+use crate::{
+    camera::Camera,
+    glowybox::Glowybox,
+    hitable::Hit,
+    hitable_list::HitableList,
+    kdtree::KDTree,
+    material::{DiffuseLight, Lambertian},
+    rect::{XYRect, XZRect, YZRect},
+    renderer::{Opt, Scene},
+    sphere::Sphere,
+    texture::ConstantTexture,
+    vec3::Vec3,
+};
+
+pub fn new(opt: &Opt) -> Scene {
+    let lookfrom = Vec3::new(20., 20., 20.);
+    let lookat = Vec3::new(0., 1., 0.);
+    let dist_to_focus = 10.0;
+    let aperture = 0.0;
+    let time_min = 0.;
+    let time_max = 1.;
+    let camera = Camera::new(
+        lookfrom,
+        lookat,
+        Vec3::new(0., 1., 0.),
+        20.,
+        opt.width as f32 / opt.height as f32,
+        aperture,
+        dist_to_focus,
+        time_min,
+        time_max,
+    );
+    let ground_color = if opt.use_accel {
+        ConstantTexture::new(Vec3::new(1.0, 0.4, 0.4))
+    } else {
+        ConstantTexture::new(Vec3::new(0.4, 1.0, 0.4))
+    };
+
+    let lights: Vec<Box<dyn Hit>> = vec![
+        Box::new(XZRect::new(
+            -100.,
+            100.,
+            -100.,
+            1000.,
+            60.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(1., 1., 1.))),
+        )),
+        Box::new(YZRect::new(
+            1.,
+            3.,
+            -1.,
+            1.,
+            4.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(4., 0., 4.))),
+        )),
+        Box::new(YZRect::new(
+            1.,
+            3.,
+            -1.,
+            1.,
+            -4.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(0., 4., 0.))),
+        )),
+        Box::new(XZRect::new(
+            -1.,
+            1.,
+            -1.,
+            1.,
+            6.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(4., 4., 0.))),
+        )),
+        Box::new(XYRect::new(
+            -1.,
+            1.,
+            1.,
+            3.,
+            -4.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(0., 0., 4.))),
+        )),
+        Box::new(XYRect::new(
+            -1.,
+            1.,
+            1.,
+            3.,
+            4.,
+            DiffuseLight::new(ConstantTexture::new(Vec3::new(0., 4., 4.))),
+        )),
+    ];
+    let mut objects: Vec<Box<dyn Hit>> = vec![
+        // Earth sized sphere
+        Box::new(Sphere::new(
+            Vec3::new(0., -1010., 0.),
+            1000.,
+            Lambertian::new(ground_color),
+        )),
+        Box::new(Glowybox::new(
+            [-4., -4., -4.].into(),
+            [4., 4., 4.].into(),
+            0.01,
+            Arc::new(Lambertian::new(ConstantTexture::new([0., 0., 0.]))),
+            Arc::new(DiffuseLight::new(ConstantTexture::new([100., 0., 0.]))),
+        )),
+    ];
+    objects.extend(lights);
+    info!("objects {:?}", objects);
+    let world: Box<dyn Hit> = if opt.use_accel {
+        Box::new(KDTree::new(objects, time_min, time_max))
+    } else {
+        Box::new(HitableList::new(objects))
+    };
+    Scene {
+        camera,
+        world,
+        subsamples: opt.subsamples,
+        num_threads: opt.num_threads,
+        width: opt.width,
+        height: opt.height,
+        ..Default::default()
+    }
+}

rtiow/renderer/src/scenes/tutorial.rs

@@ -1,18 +1,15 @@
-use crate::camera::Camera;
+use crate::{
-use crate::hitable::Hit;
+    camera::Camera,
-use crate::hitable_list::HitableList;
+    hitable::Hit,
-use crate::kdtree::KDTree;
+    hitable_list::HitableList,
-use crate::material::Dielectric;
+    kdtree::KDTree,
-use crate::material::Lambertian;
+    material::{Dielectric, Lambertian, Metal},
-use crate::material::Metal;
+    moving_sphere::MovingSphere,
-use crate::moving_sphere::MovingSphere;
+    renderer::{Opt, Scene},
-use crate::renderer::Opt;
+    sphere::Sphere,
-use crate::renderer::Scene;
+    texture::{CheckerTexture, ConstantTexture, Texture},
-use crate::sphere::Sphere;
+    vec3::Vec3,
-use crate::texture::CheckerTexture;
+};
-use crate::texture::ConstantTexture;
-use crate::texture::Texture;
-use crate::vec3::Vec3;
 
 pub fn new(opt: &Opt) -> Scene {
     let lookfrom = Vec3::new(3., 4., 2.);

rtiow/renderer/src/sphere.rs

@@ -1,13 +1,14 @@
 use std::f32::consts::PI;
 
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::material::Material;
+    material::Material,
-use crate::ray::Ray;
+    ray::Ray,
-use crate::vec3::dot;
+    vec3::{dot, Vec3},
-use crate::vec3::Vec3;
+};
 
+#[derive(Debug)]
 pub struct Sphere<M>
 where
     M: Material,

rtiow/renderer/src/texture/checker.rs

@@ -1,6 +1,6 @@
-use crate::texture::Texture;
+use crate::{texture::Texture, vec3::Vec3};
-use crate::vec3::Vec3;
 
+#[derive(Debug)]
 pub struct CheckerTexture<T>
 where
     T: Texture,

rtiow/renderer/src/texture/constant.rs

@@ -1,7 +1,6 @@
-use crate::texture::Texture;
+use crate::{texture::Texture, vec3::Vec3};
-use crate::vec3::Vec3;
 
-#[derive(Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct ConstantTexture {
     color: Vec3,
 }

rtiow/renderer/src/texture/envmap.rs

@@ -2,9 +2,10 @@ use std::f32;
 
 use image::RgbImage;
 
-use crate::texture::ImageTexture;
+use crate::{
-use crate::texture::Texture;
+    texture::{ImageTexture, Texture},
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
 #[derive(Debug)]
 pub struct EnvMap {

rtiow/renderer/src/texture/image.rs

@@ -1,7 +1,6 @@
 use image::RgbImage;
 
-use crate::texture::Texture;
+use crate::{texture::Texture, vec3::Vec3};
-use crate::vec3::Vec3;
 
 #[derive(Debug)]
 pub struct ImageTexture {

rtiow/renderer/src/texture/mandelbrot.rs

@@ -1,55 +1,15 @@
 #![allow(clippy::many_single_char_names)]
-use rand;
-use rand::Rng;
 
-use crate::texture::Texture;
+use crate::{colors::generate_palette, texture::Texture, vec3::Vec3};
-use crate::vec3::Vec3;
 
 #[derive(Debug)]
 pub struct Mandelbrot {
-    scale: f32,
     palette: Vec<Vec3>,
 }
 
-// HSV values in [0..1]
-// returns [r, g, b] values from 0 to 255
-//From https://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/
-fn hsv_to_rgb(h: f32, s: f32, v: f32) -> Vec3 {
-    let h_i = (h * 6.) as i32;
-    let f = h * 6. - h_i as f32;
-    let p = v * (1. - s);
-    let q = v * (1. - f * s);
-    let t = v * (1. - (1. - f) * s);
-    match h_i {
-        0 => Vec3::new(v, t, p),
-        1 => Vec3::new(q, v, p),
-        2 => Vec3::new(p, v, t),
-        3 => Vec3::new(p, q, v),
-        4 => Vec3::new(t, p, v),
-        5 => Vec3::new(v, p, q),
-        _ => panic!("Unknown H value {}", h_i),
-    }
-}
-
-fn generate_palette(num: usize) -> Vec<Vec3> {
-    let mut rng = rand::thread_rng();
-    let mut random = || rng.gen();
-    // use golden ratio
-    let golden_ratio_conjugate = 0.618_034;
-    let mut h = random();
-    (0..num)
-        .map(|_| {
-            h += golden_ratio_conjugate;
-            h %= 1.0;
-            hsv_to_rgb(h, 0.99, 0.99)
-        })
-        .collect()
-}
-
 impl Default for Mandelbrot {
     fn default() -> Self {
         Mandelbrot {
-            scale: 2.0,
             palette: generate_palette(10),
         }
     }

rtiow/renderer/src/texture/mod.rs

@@ -4,18 +4,16 @@ mod envmap;
 mod image;
 mod mandelbrot;
 mod noise;
-pub use crate::texture::checker::CheckerTexture;
+pub use crate::texture::{
-pub use crate::texture::constant::ConstantTexture;
+    checker::CheckerTexture, constant::ConstantTexture, envmap::EnvMap, image::ImageTexture,
-pub use crate::texture::envmap::EnvMap;
+    mandelbrot::Mandelbrot, noise::NoiseTexture,
-pub use crate::texture::image::ImageTexture;
+};
-pub use crate::texture::mandelbrot::Mandelbrot;
-pub use crate::texture::noise::NoiseTexture;
 
-use std::sync::Arc;
+use std::{fmt::Debug, sync::Arc};
 
 use crate::vec3::Vec3;
 
-pub trait Texture: Send + Sync {
+pub trait Texture: Send + Sync + Debug {
     fn value(&self, u: f32, v: f32, p: Vec3) -> Vec3;
 }
 
@@ -31,6 +29,12 @@ impl Texture for Box<dyn Texture> {
     }
 }
 
+impl Texture for [f32; 3] {
+    fn value(&self, u: f32, v: f32, p: Vec3) -> Vec3 {
+        (*self).into()
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;

rtiow/renderer/src/texture/noise.rs

@@ -1,8 +1,10 @@
-use crate::noise::NoiseSource;
+use crate::{
-use crate::noise::NoiseType;
+    noise::{NoiseSource, NoiseType},
-use crate::texture::Texture;
+    texture::Texture,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
+#[derive(Debug)]
 pub struct NoiseTexture<N>
 where
     N: NoiseSource,

rtiow/renderer/src/translate.rs

@@ -1,9 +1,11 @@
-use crate::aabb::AABB;
+use crate::{
-use crate::hitable::Hit;
+    aabb::AABB,
-use crate::hitable::HitRecord;
+    hitable::{Hit, HitRecord},
-use crate::ray::Ray;
+    ray::Ray,
-use crate::vec3::Vec3;
+    vec3::Vec3,
+};
 
+#[derive(Debug)]
 pub struct Translate<H>
 where
     H: Hit,

rtiow/renderer/src/triangles.rs

@@ -0,0 +1,168 @@
+use std::f32::EPSILON;
+
+use stl::STL;
+
+use crate::{
+    aabb::AABB,
+    hitable::{Hit, HitRecord},
+    material::Material,
+    ray::Ray,
+    vec3::{cross, dot, Vec3},
+};
+
+#[derive(Debug)]
+pub struct Triangle {
+    normal: Vec3,
+    verts: [Vec3; 3],
+    // Precomputed data
+}
+
+#[derive(Debug)]
+pub struct Triangles<M>
+where
+    M: Material,
+{
+    pub triangles: Vec<Triangle>,
+    pub bbox: AABB,
+    material: M,
+}
+
+impl<M> Triangles<M>
+where
+    M: Material,
+{
+    pub fn new(stl: &STL, material: M, scale_factor: f32) -> Triangles<M> {
+        let triangles: Vec<_> = stl
+            .triangles
+            .iter()
+            .map(|t| {
+                let v0 = t.verts[0] * scale_factor;
+                let v1 = t.verts[1] * scale_factor;
+                let v2 = t.verts[2] * scale_factor;
+                Triangle {
+                    normal: t.normal,
+                    verts: [v0, v1, v2],
+                }
+            })
+            .collect();
+        let (min, max) = triangles.iter().fold(
+            (Vec3::from(f32::MAX), Vec3::from(f32::MIN)),
+            |(min, max), t| {
+                let t_min_x = t.verts[0].x.min(t.verts[1].x.min(t.verts[2].x));
+                let t_min_y = t.verts[0].y.min(t.verts[1].y.min(t.verts[2].y));
+                let t_min_z = t.verts[0].z.min(t.verts[1].z.min(t.verts[2].z));
+                let t_max_x = t.verts[0].x.max(t.verts[1].x.max(t.verts[2].x));
+                let t_max_y = t.verts[0].y.max(t.verts[1].y.max(t.verts[2].y));
+                let t_max_z = t.verts[0].z.max(t.verts[1].z.max(t.verts[2].z));
+
+                (
+                    Vec3::from([min.x.min(t_min_x), min.y.min(t_min_y), min.z.min(t_min_z)]),
+                    Vec3::from([max.x.max(t_max_x), max.y.max(t_max_y), max.z.max(t_max_z)]),
+                )
+            },
+        );
+        let bbox = AABB::new(min, max);
+        Triangles {
+            triangles,
+            bbox,
+            material,
+        }
+    }
+}
+
+/// Based on https://www.scratchapixel.com/lessons/3d-basic-rendering/ray-tracing-rendering-a-triangle/moller-trumbore-ray-triangle-intersection.html
+fn ray_triangle_intersect_moller_trumbore(r: Ray, tri: &Triangle) -> Option<RayTriangleResult> {
+    // #ifdef MOLLER_TRUMBORE
+    //     Vec3f v0v1 = v1 - v0;
+    //     Vec3f v0v2 = v2 - v0;
+    //     Vec3f pvec = dir.crossProduct(v0v2);
+    //     float det = v0v1.dotProduct(pvec);
+    // #ifdef CULLING
+    //     // if the determinant is negative, the triangle is 'back facing'
+    //     // if the determinant is close to 0, the ray misses the triangle
+    //     if (det < kEpsilon) return false;
+    // #else
+    //     // ray and triangle are parallel if det is close to 0
+    //     if (fabs(det) < kEpsilon) return false;
+    // #endif
+    //     float invDet = 1 / det;
+    //
+    //     Vec3f tvec = orig - v0;
+    //     u = tvec.dotProduct(pvec) * invDet;
+    //     if (u < 0 || u > 1) return false;
+    //
+    //     Vec3f qvec = tvec.crossProduct(v0v1);
+    //     v = dir.dotProduct(qvec) * invDet;
+    //     if (v < 0 || u + v > 1) return false;
+    //
+    //     t = v0v2.dotProduct(qvec) * invDet;
+    //
+    let v0 = tri.verts[0];
+    let v1 = tri.verts[1];
+    let v2 = tri.verts[2];
+
+    let v0v1 = v1 - v0;
+    let v0v2 = v2 - v0;
+    let p = cross(r.direction, v0v2);
+    let det = dot(v0v1, p);
+    if det < EPSILON {
+        return None;
+    }
+
+    let inv_det = 1. / det;
+
+    let t = r.origin - v0;
+    let u = dot(t, p) * inv_det;
+    if u < 0. || u > 1. {
+        return None;
+    }
+
+    let q = cross(t, v0v1);
+    let v = dot(r.direction, q) * inv_det;
+    if v < 0. || u + v > 1. {
+        return None;
+    }
+    let t = dot(v0v2, q) * inv_det;
+
+    if t > EPSILON {
+        return Some(RayTriangleResult {
+            t,
+            p: r.origin + r.direction * t,
+        });
+    }
+    None
+}
+
+impl<M> Hit for Triangles<M>
+where
+    M: Material,
+{
+    fn hit(&self, r: Ray, _t_min: f32, _t_max: f32) -> Option<HitRecord> {
+        // TODO(wathiede): add an acceleration structure to more cheaply skip some triangles.
+        for tri in &self.triangles {
+            if let Some(RayTriangleResult { t, p }) = ray_triangle_intersect_moller_trumbore(r, tri)
+            {
+                //if let Some(RayTriangleResult { t, p }) = ray_triangle_intersect_geometric(r, tri) {
+                // We don't support UV (yet?).
+                let uv = (0.5, 0.5);
+                return Some(HitRecord {
+                    t,
+                    uv,
+                    p,
+                    normal: tri.normal,
+                    material: &self.material,
+                });
+            }
+        }
+        None
+    }
+
+    fn bounding_box(&self, _t_min: f32, _t_max: f32) -> Option<AABB> {
+        Some(self.bbox)
+    }
+}
+
+struct RayTriangleResult {
+    t: f32,
+    p: Vec3,
+}

rtiow/renderer/src/vec3.rs

@@ -1,279 +1 @@
-use std::convert::From;
+pub use vec3::*;
-use std::fmt;
-use std::num::ParseFloatError;
-use std::ops::Add;
-use std::ops::Div;
-use std::ops::Index;
-use std::ops::Mul;
-use std::ops::Neg;
-use std::ops::Sub;
-use std::str;
-
-use serde_derive::Deserialize;
-use serde_derive::Serialize;
-
-#[derive(Default, Debug, Deserialize, Serialize, PartialEq, Copy, Clone)]
-pub struct Vec3 {
-    pub x: f32,
-    pub y: f32,
-    pub z: f32,
-}
-
-pub fn cross(v1: Vec3, v2: Vec3) -> Vec3 {
-    Vec3 {
-        x: v1.y * v2.z - v1.z * v2.y,
-        y: v1.z * v2.x - v1.x * v2.z,
-        z: v1.x * v2.y - v1.y * v2.x,
-    }
-}
-
-pub fn dot(v1: Vec3, v2: Vec3) -> f32 {
-    v1.x * v2.x + v1.y * v2.y + v1.z * v2.z
-}
-
-impl Vec3 {
-    pub fn new(x: f32, y: f32, z: f32) -> Vec3 {
-        Vec3 { x, y, z }
-    }
-
-    pub fn min(self) -> f32 {
-        self.x.min(self.y).min(self.z)
-    }
-
-    pub fn max(self) -> f32 {
-        self.x.max(self.y).max(self.z)
-    }
-
-    pub fn length(self) -> f32 {
-        self.squared_length().sqrt()
-    }
-
-    pub fn squared_length(self) -> f32 {
-        self.x * self.x + self.y * self.y + self.z * self.z
-    }
-
-    pub fn unit_vector(self) -> Vec3 {
-        self / self.length()
-    }
-
-    pub fn make_unit_vector(&mut self) {
-        *self = self.unit_vector();
-    }
-}
-
-impl From<[f32; 3]> for Vec3 {
-    fn from(v: [f32; 3]) -> Self {
-        Vec3 {
-            x: v[0],
-            y: v[1],
-            z: v[2],
-        }
-    }
-}
-
-impl fmt::Display for Vec3 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{} {} {}", self.x, self.y, self.z)
-    }
-}
-
-impl str::FromStr for Vec3 {
-    type Err = ParseFloatError;
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let coords: Vec<&str> = s.split(' ').collect();
-        Ok(Vec3 {
-            x: coords[0].parse::<f32>()?,
-            y: coords[1].parse::<f32>()?,
-            z: coords[2].parse::<f32>()?,
-        })
-    }
-}
-
-impl Add<f32> for Vec3 {
-    type Output = Vec3;
-
-    fn add(self, r: f32) -> Vec3 {
-        Vec3 {
-            x: self.x + r,
-            y: self.y + r,
-            z: self.z + r,
-        }
-    }
-}
-
-impl Add for Vec3 {
-    type Output = Vec3;
-
-    fn add(self, r: Vec3) -> Vec3 {
-        Vec3 {
-            x: self.x + r.x,
-            y: self.y + r.y,
-            z: self.z + r.z,
-        }
-    }
-}
-
-impl Div<Vec3> for f32 {
-    type Output = Vec3;
-
-    fn div(self, r: Vec3) -> Vec3 {
-        Vec3 {
-            x: self / r.x,
-            y: self / r.y,
-            z: self / r.z,
-        }
-    }
-}
-
-impl Div<f32> for Vec3 {
-    type Output = Vec3;
-
-    fn div(self, r: f32) -> Vec3 {
-        Vec3 {
-            x: self.x / r,
-            y: self.y / r,
-            z: self.z / r,
-        }
-    }
-}
-
-impl Index<usize> for Vec3 {
-    type Output = f32;
-    fn index(&self, idx: usize) -> &f32 {
-        match idx {
-            0 => &self.x,
-            1 => &self.y,
-            2 => &self.z,
-            _ => panic!("idx {} out of range for vec3", idx),
-        }
-    }
-}
-
-impl Mul for Vec3 {
-    type Output = Vec3;
-
-    fn mul(self, r: Vec3) -> Vec3 {
-        Vec3 {
-            x: self.x * r.x,
-            y: self.y * r.y,
-            z: self.z * r.z,
-        }
-    }
-}
-
-impl Mul<Vec3> for f32 {
-    type Output = Vec3;
-
-    fn mul(self, v: Vec3) -> Vec3 {
-        Vec3 {
-            x: v.x * self,
-            y: v.y * self,
-            z: v.z * self,
-        }
-    }
-}
-
-impl Mul<f32> for Vec3 {
-    type Output = Vec3;
-
-    fn mul(self, r: f32) -> Vec3 {
-        Vec3 {
-            x: self.x * r,
-            y: self.y * r,
-            z: self.z * r,
-        }
-    }
-}
-
-impl Neg for Vec3 {
-    type Output = Vec3;
-
-    fn neg(self) -> Vec3 {
-        -1. * self
-    }
-}
-
-impl Sub for Vec3 {
-    type Output = Vec3;
-
-    fn sub(self, r: Vec3) -> Vec3 {
-        Vec3 {
-            x: self.x - r.x,
-            y: self.y - r.y,
-            z: self.z - r.z,
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use std::f32::consts::PI;
-    use std::str::FromStr;
-
-    use super::*;
-
-    #[test]
-    fn vec_add() {
-        let v0 = Vec3::new(1., 2., 3.);
-        let v1 = Vec3::new(1., 1., 1.);
-        assert_eq!(v0 + v1, Vec3::new(2., 3., 4.));
-    }
-
-    #[test]
-    fn vec_div() {
-        let v0 = Vec3::new(1., 2., 4.);
-        assert_eq!(v0 / 2., Vec3::new(0.5, 1., 2.));
-    }
-
-    #[test]
-    fn vec_mul() {
-        let v0 = Vec3::new(1., 2., 4.);
-        assert_eq!(v0 * 0.5, Vec3::new(0.5, 1., 2.));
-        assert_eq!(v0 * v0, Vec3::new(1., 4., 16.));
-    }
-
-    #[test]
-    fn vec_sub() {
-        let v0 = Vec3::new(1., 2., 3.);
-        let v1 = Vec3::new(1., 1., 1.);
-        assert_eq!(v0 - v1, Vec3::new(0., 1., 2.));
-    }
-
-    #[test]
-    fn vec_idx() {
-        let v0 = Vec3::new(1., 2., 3.);
-        assert_eq!(v0[2], 3.);
-    }
-
-    #[test]
-    fn vec_display() {
-        let v0 = Vec3::new(1., 2., 3.);
-        assert_eq!(format!("{}", v0), "1 2 3".to_owned());
-    }
-
-    #[test]
-    fn vec_from_str() {
-        assert_eq!(Vec3::from_str("1. 2. 3.").unwrap(), Vec3::new(1., 2., 3.));
-    }
-
-    #[test]
-    fn vec_str_roundtrip() {
-        let v = Vec3::from_str("1 2 3").unwrap();
-        let s = format!("{}", v);
-        assert_eq!(v, Vec3::from_str(&s).unwrap());
-    }
-
-    #[test]
-    fn vec_dot() {
-        let v0 = Vec3::new(1., 0., 0.);
-        let v1 = Vec3::new(-1., 0., 0.);
-        assert_eq!(dot(v0, v1), v0.length() * v1.length() * PI.cos());
-    }
-
-    #[test]
-    fn vec_cross() {
-        let v0 = Vec3::new(1., 0., 0.);
-        let v1 = Vec3::new(0., 1., 0.);
-        assert_eq!(cross(v0, v1), Vec3::new(0., 0., 1.));
-    }
-}

rtiow/renderer/stls/dragon.stl

@@ -0,0 +1 @@
+stanford_dragon.stl

rtiow/renderer/stls/stanford_dragon-lowres.stl

@@ -0,0 +1 @@
+/home/wathiede/3dprint/stl/stanford_dragon-lowres.stl

rtiow/tracer/Cargo.toml

@@ -2,12 +2,16 @@
 name = "tracer"
 version = "0.1.0"
 authors = ["Bill Thiede <git@xinu.tv>"]
-edition = "2018"
+edition = "2021"
+default-run = "tracer"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-log = "0.4.5"
+anyhow = "1.0.69"
+log = "0.4.17"
 renderer = { path = "../renderer" }
-stderrlog = "0.4.1"
+stderrlog = "0.4.3"
-structopt = "0.2.10"
+structopt = "0.2.18"
+strum = "0.24.1"
+toml = "0.7.2"

rtiow/tracer/configs/test.toml

@@ -0,0 +1,74 @@
+[scene]
+width = 768
+height = 512
+subsamples = 100
+
+[camera]
+lookfrom = [0.0, 50.0, 100.0]
+lookat = [0.0, 10.0, 0.0]
+fov = 45
+aperture = 0.0
+focus_dist = 10.0
+time_min = 0.0
+time_max = 1.0
+
+[[materials]]
+name = "light1"
+type = "isotropic"
+texture = [20, 10, 10]
+[[materials]]
+name = "yellow"
+type = "isotropic"
+texture = [1, 1, 0]
+[[materials]]
+name = "magenta"
+type = "lambertian"
+texture = [1, 0, 1]
+[[materials]]
+name = "green"
+type = "diffuse_light"
+texture = [0, 1, 0]
+[[materials]]
+name = "metal"
+type = "metal"
+albedo = [1, 1, 1]
+fuzzy = 0
+[[materials]]
+name = "glass"
+type = "dielectric"
+ref_idx = 1.5
+
+
+[[hitables]]
+type = "sphere"
+center = [-30.0, 0.0, 0.0]
+radius = 10
+material_name = "yellow"
+[[hitables]]
+type = "sphere"
+center = [30.0, 0.0, 0.0]
+radius = 10
+material_name = "green"
+[[hitables]]
+type = "sphere"
+center = [0.0, -10.0, 0.0]
+radius = 10
+material_name = "metal"
+[[hitables]]
+type = "sphere"
+center = [0.0, 0.0, -30.0]
+radius = 10
+material_name = "magenta"
+[[hitables]]
+type = "stl"
+path = "/net/nasx.h.xinu.tv/x/3dprint/stl/stanford_dragon.stl"
+scale = 200
+material_name = "glass"
+#[[hitables]]
+#type = "sphere"
+#center = [0.0, 50.0, -100.0]
+#radius = 10
+#material_name = "light1"
+
+[envmap]
+path = "/home/wathiede/src/xinu.tv/raytracers/rtiow/renderer/images/52681723945_e1d94d3df9_6k.jpg"

rtiow/tracer/rustfmt.toml

@@ -0,0 +1,2 @@
+imports_granularity = "Crate"
+format_code_in_doc_comments = true

rtiow/tracer/src/main.rs

@@ -1,14 +1,17 @@
 #![warn(unused_extern_crates)]
-use std::fs;
+use std::{fs, time::Instant};
 
+use anyhow::Result;
 #[cfg(feature = "profile")]
 use cpuprofiler::PROFILER;
 use log::info;
-use stderrlog;
 use structopt::StructOpt;
 
-use renderer::renderer::render;
+use renderer::{
-use renderer::renderer::Opt;
+    parser::Config,
+    renderer::{render, Model, Opt},
+};
+use strum::VariantNames;
 
 #[cfg(not(feature = "profile"))]
 struct MockTimer;
@@ -36,15 +39,36 @@ impl MockProfiler {
 #[cfg(not(feature = "profile"))]
 static PROFILER: MockProfiler = MockProfiler {};
 
-fn main() -> Result<(), std::io::Error> {
+fn main() -> Result<()> {
+    let start_time = Instant::now();
     stderrlog::new()
         .verbosity(3)
         .timestamp(stderrlog::Timestamp::Millisecond)
         .init()
         .unwrap();
     let opt = Opt::from_args();
-    info!("{:?}", opt);
+    if opt.model.is_none() && opt.config.is_none() {
-    let scene = opt.model.scene(&opt);
+        eprintln!(
+            "--config <path> or --model should be one of {:?}",
+            Model::VARIANTS
+        );
+        return Ok(());
+    }
+    if opt.model.is_some() && opt.config.is_some() {
+        eprintln!("only specify one of --config or --model");
+        return Ok(());
+    }
+    info!("{:#?}", opt);
+    let scene = match (&opt.model, &opt.config) {
+        (Some(model), None) => model.scene(&opt),
+        (None, Some(config)) => {
+            let s = std::fs::read_to_string(config)?;
+            let cfg: Config = toml::from_str(&s)?;
+            println!("{:#?}", cfg);
+            cfg.try_into()?
+        }
+        _ => unreachable!(),
+    };
     fs::create_dir_all(&opt.output)?;
     if opt.pprof.is_some() && !cfg!(feature = "profile") {
         panic!("profiling disabled at compile time, but -pprof specified");
@@ -56,11 +80,13 @@ fn main() -> Result<(), std::io::Error> {
             .start(pprof_path.to_str().unwrap().as_bytes())
             .unwrap();
     }
-    let res = render(scene, &opt.output);
+    let res = render(scene, &opt.output, &opt.tev_addr);
     if let Some(pprof_path) = &opt.pprof {
         info!("Saving pprof to {}", pprof_path.to_string_lossy());
         PROFILER.lock().unwrap().stop().unwrap();
     }
 
-    res
+    let time_diff = Instant::now() - start_time;
+    info!("Total runtime {} seconds", time_diff.as_secs_f32());
+    Ok(res?)
 }