raytracers/rtchallenge/src/patterns.rs

445 lines
14 KiB
Rust

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(())
}
}
}