Add ConstantMedium and cornell_smoke scene.

Shows the ability to compute smoke as a wrapper for anything implementing Hit.

rtiow/src/constant_medium.rs

@@ -0,0 +1,83 @@
+use std;
+
+use rand;
+use rand::Rng;
+
+use aabb::AABB;
+use hitable::Hit;
+use hitable::HitRecord;
+use material::Material;
+use ray::Ray;
+use vec3::Vec3;
+
+pub struct ConstantMedium<H, M>
+where
+    H: Hit,
+    M: Material,
+{
+    density: f32,
+    material: M,
+    hitable: H,
+}
+
+impl<H, M> ConstantMedium<H, M>
+where
+    H: Hit,
+    M: Material,
+{
+    pub fn new(hitable: H, density: f32, material: M) -> ConstantMedium<H, M> {
+        ConstantMedium {
+            density,
+            material,
+            hitable,
+        }
+    }
+}
+
+impl<H, M> Hit for ConstantMedium<H, M>
+where
+    H: Hit,
+    M: Material,
+{
+    fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+        let mut rng = rand::thread_rng();
+        if let Some(mut rec1) = self.hitable.hit(r, std::f32::MIN, std::f32::MAX) {
+            if let Some(mut rec2) = self.hitable.hit(r, rec1.t + 0.001, std::f32::MAX) {
+                if rec1.t < t_min {
+                    rec1.t = t_min;
+                }
+                if rec2.t > t_max {
+                    rec2.t = t_max;
+                }
+                if rec1.t >= rec2.t {
+                    return None;
+                }
+                if rec1.t < 0. {
+                    rec1.t = 0.;
+                }
+                let distance_inside_boundary = (rec2.t - rec1.t) * r.direction.length();
+                let hit_distance = -(1. / self.density) * rng.gen_range::<f32>(0., 1.).ln();
+                if hit_distance < distance_inside_boundary {
+                    let t = rec1.t + hit_distance / r.direction.length();
+                    let normal = Vec3::new(
+                        rng.gen_range::<f32>(0., 1.),
+                        rng.gen_range::<f32>(0., 1.),
+                        rng.gen_range::<f32>(0., 1.),
+                    ).unit_vector();
+                    return Some(HitRecord {
+                        t,
+                        p: r.point_at_parameter(t),
+                        normal,
+                        material: &self.material,
+                        uv: (0., 0.),
+                    });
+                }
+            }
+        }
+        None
+    }
+
+    fn bounding_box(&self, t_min: f32, t_max: f32) -> Option<AABB> {
+        self.hitable.bounding_box(t_min, t_max)
+    }
+}

rtiow/src/lib.rs

@@ -1,6 +1,7 @@
 pub mod aabb;
 pub mod bvh;
 pub mod camera;
+pub mod constant_medium;
 pub mod cuboid;
 pub mod flip_normals;
 pub mod hitable;

rtiow/src/material.rs

@@ -214,3 +214,25 @@ where
         self.emit.value(u, v, p)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use texture::ConstantTexture;
+
+    #[test]
+    fn arc_material() {
+        let white: Arc<Material> =
+            Arc::new(Lambertian::new(ConstantTexture::new([0.73, 0.73, 0.73])));
+
+        fn material_fn<M>(m: M)
+        where
+            M: Material,
+        {
+            let _ = m;
+        }
+
+        material_fn(Arc::clone(&white));
+        material_fn(Arc::clone(&white));
+    }
+}

rtiow/src/renderer.rs

@@ -27,6 +27,7 @@ pub enum Model {
     BVH,
     Test,
     CornellBox,
+    CornellSmoke,
 }
 
 impl Model {
@@ -38,6 +39,7 @@ impl Model {
             Model::BVH => scenes::bvh::new(&opt),
             Model::Test => scenes::test::new(&opt),
             Model::CornellBox => scenes::cornell_box::new(&opt),
+            Model::CornellSmoke => scenes::cornell_smoke::new(&opt),
         }
     }
 }
@@ -61,6 +63,7 @@ impl str::FromStr for Model {
             "bvh" => Ok(Model::BVH),
             "test" => Ok(Model::Test),
             "cornell_box" => Ok(Model::CornellBox),
+            "cornell_smoke" => Ok(Model::CornellSmoke),
             _ => Err(ModelParseError(s.to_owned())),
         }
     }
@@ -78,8 +81,9 @@ 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, one of: "bench", "book", "tutorial", "bvh", "test", "cornell_box",
-    #[structopt(long = "model", default_value = "book")]
+    /// "cornell_smoke"
+    #[structopt(long = "model", default_value = "cornell_smoke")]
     pub model: Model,
     /// Path to store pprof profile data, i.e. /tmp/cpuprofile.pprof
     #[structopt(long = "pprof", parse(from_os_str))]

rtiow/src/scenes/cornell_smoke.rs

@@ -0,0 +1,122 @@
+use std::sync::Arc;
+
+use camera::Camera;
+use constant_medium::ConstantMedium;
+use cuboid::Cuboid;
+use flip_normals::FlipNormals;
+use hitable::Hit;
+use hitable_list::HitableList;
+use kdtree::KDTree;
+use material::DiffuseLight;
+use material::Lambertian;
+use material::Material;
+use rect::XYRect;
+use rect::XZRect;
+use rect::YZRect;
+use renderer::Opt;
+use renderer::Scene;
+use rotate::RotateY;
+use texture::ConstantTexture;
+use translate::Translate;
+use vec3::Vec3;
+
+pub fn new(opt: &Opt) -> Scene {
+    let lookfrom = Vec3::new(278., 278., -800.);
+    let lookat = Vec3::new(278., 278., 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.),
+        40.,
+        opt.width as f32 / opt.height as f32,
+        aperture,
+        dist_to_focus,
+        time_min,
+        time_max,
+    );
+
+    let red = Lambertian::new(ConstantTexture::new([0.65, 0.05, 0.05]));
+    let white: Arc<Material> = Arc::new(Lambertian::new(ConstantTexture::new([0.73, 0.73, 0.73])));
+    let green = Lambertian::new(ConstantTexture::new([0.12, 0.45, 0.15]));
+    let light = DiffuseLight::new(ConstantTexture::new([7., 7., 7.]));
+
+    let objects: Vec<Box<Hit>> = vec![
+        // White smoke box on the right
+        Box::new(ConstantMedium::new(
+            Translate::new(
+                RotateY::new(
+                    Cuboid::new(
+                        Vec3::new(0., 0., 0.),
+                        Vec3::new(165., 165., 165.),
+                        Arc::clone(&white),
+                    ),
+                    -18.,
+                ),
+                Vec3::new(130., 0., 65.),
+            ),
+            0.01,
+            Lambertian::new(ConstantTexture::new([1., 1., 1.])),
+        )),
+        // Black smoke box on the left
+        Box::new(ConstantMedium::new(
+            Translate::new(
+                RotateY::new(
+                    Cuboid::new(
+                        Vec3::new(0., 0., 0.),
+                        Vec3::new(165., 330., 165.),
+                        Arc::clone(&white),
+                    ),
+                    15.,
+                ),
+                Vec3::new(265., 0., 295.),
+            ),
+            0.01,
+            Lambertian::new(ConstantTexture::new([0., 0., 0.])),
+        )),
+        // Green wall left
+        Box::new(FlipNormals::new(YZRect::new(
+            0., 555., 0., 555., 555., green,
+        ))),
+        // Red floor right
+        Box::new(YZRect::new(0., 555., 0., 555., 0., red)),
+        // Light in ceiling
+        Box::new(XZRect::new(113., 443., 127., 432., 554., light)),
+        // Grey ceiling
+        Box::new(FlipNormals::new(XZRect::new(
+            0.,
+            555.,
+            0.,
+            555.,
+            555.,
+            Arc::clone(&white),
+        ))),
+        // Grey floor
+        Box::new(XZRect::new(0., 555., 0., 555., 0., Arc::clone(&white))),
+        // Grey back wall
+        Box::new(FlipNormals::new(XYRect::new(
+            0.,
+            555.,
+            0.,
+            555.,
+            555.,
+            Arc::clone(&white),
+        ))),
+    ];
+    let world: Box<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,
+        width: opt.width,
+        height: opt.height,
+        global_illumination: false,
+    }
+}

rtiow/src/scenes/mod.rs

@@ -2,5 +2,6 @@ pub mod bench;
 pub mod book;
 pub mod bvh;
 pub mod cornell_box;
+pub mod cornell_smoke;
 pub mod test;
 pub mod tutorial;