library: use enum_dispatch on Object related trait

This allows for easier testing (notable allowing for comparisons),
better performance (thanks to inlining instead of vtable indirection),
and should ease the deserialization of `Material`, `Shape`, and
`Texture` traits. This should allow `Object` to be deserialized easily.

src/material/mod.rs

@@ -1,7 +1,15 @@
 use super::core::color::LinearColor;
 use super::Point2D;
 
+/// All the existing `Material` implementation.
+#[enum_dispatch::enum_dispatch]
+#[derive(Debug, PartialEq)]
+pub enum MaterialEnum {
+    UniformMaterial,
+}
+
 /// Represent the physical light properties of an object in the scene;
+#[enum_dispatch::enum_dispatch(MaterialEnum)]
 pub trait Material: std::fmt::Debug {
     /// The diffuse component on a texel point.
     fn diffuse(&self, point: Point2D) -> LinearColor;

src/material/uniform.rs

@@ -4,7 +4,7 @@ use crate::Point2D;
 use serde::Deserialize;
 
 /// A material with the same characteristics on all points.
-#[derive(Debug, PartialEq, Deserialize)]
+#[derive(Clone, Debug, PartialEq, Deserialize)]
 pub struct UniformMaterial {
     diffuse: LinearColor,
     specular: LinearColor,

src/render/object.rs

@@ -1,17 +1,17 @@
-use crate::material::Material;
-use crate::shape::Shape;
-use crate::texture::Texture;
+use crate::material::MaterialEnum;
+use crate::shape::ShapeEnum;
+use crate::texture::TextureEnum;
 
 /// An object being rendered in the scene.
-#[derive(Debug)]
-pub struct Object<'a> {
-    pub shape: &'a dyn Shape,
-    pub material: &'a dyn Material,
-    pub texture: &'a dyn Texture,
+#[derive(Debug, PartialEq)]
+pub struct Object {
+    pub shape: ShapeEnum,
+    pub material: MaterialEnum,
+    pub texture: TextureEnum,
 }
 
-impl<'a> Object<'a> {
-    pub fn new(shape: &'a dyn Shape, material: &'a dyn Material, texture: &'a dyn Texture) -> Self {
+impl Object {
+    pub fn new(shape: ShapeEnum, material: MaterialEnum, texture: TextureEnum) -> Self {
         Object {
             shape,
             material,
@@ -23,70 +23,33 @@ impl<'a> Object<'a> {
 #[cfg(test)]
 mod test {
     use super::*;
-
     use crate::core::color::LinearColor;
-    use crate::*;
-    use bvh::{
-        aabb::{Bounded, AABB},
-        ray::Ray,
-    };
-
-    /// NOTE(Bruno): those dummy implementations could be used somewhere else ?
-
-    #[derive(Debug)]
-    struct DummyShape {}
-
-    impl Bounded for DummyShape {
-        fn aabb(&self) -> AABB {
-            todo!()
-        }
-    }
-
-    impl Shape for DummyShape {
-        /// Return the distance at which the object intersects with the ray, or None if it does not.
-        fn intersect(&self, _: &Ray) -> Option<f32> {
-            todo!()
-        }
-        /// Return the unit vector corresponding to the normal at this point of the shape.
-        fn normal(&self, _: &Point) -> Vector {
-            todo!()
-        }
-        /// Project the point from the shape's surface to its texel coordinates.
-        fn project_texel(&self, _: &Point) -> Point2D {
-            todo!()
-        }
-    }
-
-    #[derive(Debug)]
-    struct DummyMaterial {}
-
-    impl Material for DummyMaterial {
-        fn diffuse(&self, _: Point2D) -> LinearColor {
-            todo!()
-        }
-        fn specular(&self, _: Point2D) -> LinearColor {
-            todo!()
-        }
-        fn reflectivity(&self, _: Point2D) -> f32 {
-            todo!()
-        }
-    }
-
-    #[derive(Debug)]
-    struct DummyTexture {}
-
-    impl Texture for DummyTexture {
-        fn texel_color(&self, _: Point2D) -> LinearColor {
-            todo!()
-        }
-    }
+    use crate::material::UniformMaterial;
+    use crate::shape::Sphere;
+    use crate::texture::UniformTexture;
+    use crate::Point;
 
     #[test]
     fn new_works() {
-        let shape = DummyShape {};
-        let material = DummyMaterial {};
-        let texture = DummyTexture {};
-        let _ = Object::new(&shape, &material, &texture);
-        // Can't compare the results... Just make sure the new compiles.
+        let shape = Sphere::new(Point::origin(), 1.);
+        let material = UniformMaterial::new(
+            LinearColor::new(0.5, 0.5, 0.5),
+            LinearColor::new(1., 1., 1.),
+            0.5,
+        );
+        let texture = UniformTexture::new(LinearColor::new(0.25, 0.5, 1.));
+        let object = Object::new(
+            shape.clone().into(),
+            material.clone().into(),
+            texture.clone().into(),
+        );
+        assert_eq!(
+            object,
+            Object {
+                shape: shape.into(),
+                material: material.into(),
+                texture: texture.into(),
+            }
+        )
     }
 }

src/render/scene.rs

@@ -1,26 +1,30 @@
 use super::{light_aggregate::LightAggregate, object::Object};
-use crate::core::Camera;
-use crate::core::LinearColor;
-use crate::{Point, Point2D, Vector};
+use crate::{
+    core::{Camera, LinearColor},
+    material::Material,
+    shape::Shape,
+    texture::Texture,
+    {Point, Point2D, Vector},
+};
 use bvh::ray::Ray;
 use image::RgbImage;
 use rand::prelude::thread_rng;
 use rand::Rng;
 
 /// Represent the scene being rendered.
-pub struct Scene<'a> {
+pub struct Scene {
     camera: Camera,
     lights: LightAggregate,
-    objects: Vec<Object<'a>>,
+    objects: Vec<Object>,
     aliasing_limit: u32,
     reflection_limit: u32,
 }
 
-impl<'a> Scene<'a> {
+impl Scene {
     pub fn new(
         camera: Camera,
         lights: LightAggregate,
-        objects: Vec<Object<'a>>,
+        objects: Vec<Object>,
         aliasing_limit: u32,
         reflection_limit: u32,
     ) -> Self {

src/shape/mod.rs

@@ -1,15 +1,34 @@
 use super::{Point, Point2D, Vector};
-use bvh::aabb::Bounded;
-use bvh::ray::Ray;
+use bvh::{
+    aabb::{Bounded, AABB},
+    ray::Ray,
+};
+
+/// All the existing `Shape` implementation.
+#[enum_dispatch::enum_dispatch]
+#[derive(Debug, PartialEq)]
+pub enum ShapeEnum {
+    Sphere,
+    Triangle,
+}
 
 /// Represent an abstract shape inside the scene.
-pub trait Shape: Bounded + std::fmt::Debug {
+#[enum_dispatch::enum_dispatch(ShapeEnum)]
+pub trait Shape: std::fmt::Debug {
     /// Return the distance at which the object intersects with the ray, or None if it does not.
     fn intersect(&self, ray: &Ray) -> Option<f32>;
     /// Return the unit vector corresponding to the normal at this point of the shape.
     fn normal(&self, point: &Point) -> Vector;
     /// Project the point from the shape's surface to its texel coordinates.
     fn project_texel(&self, point: &Point) -> Point2D;
+    /// Enclose the `Shape` in an axi-aligned bounding-box.
+    fn aabb(&self) -> AABB;
+}
+
+impl Bounded for dyn Shape {
+    fn aabb(&self) -> AABB {
+        self.aabb()
+    }
 }
 
 pub mod sphere;

src/shape/sphere.rs

@@ -1,11 +1,11 @@
 use super::Shape;
 use crate::{Point, Point2D, Vector};
-use bvh::aabb::{Bounded, AABB};
+use bvh::aabb::AABB;
 use bvh::ray::Ray;
 use serde::Deserialize;
 
 /// Represent a sphere shape inside the scene.
-#[derive(Debug, PartialEq, Deserialize)]
+#[derive(Clone, Debug, PartialEq, Deserialize)]
 pub struct Sphere {
     /// The sphere is inverted if it is expected to be seen from the inside.
     inverted: bool,
@@ -35,15 +35,6 @@ impl Sphere {
     }
 }
 
-impl Bounded for Sphere {
-    fn aabb(&self) -> AABB {
-        let delt = Vector::new(self.radius, self.radius, self.radius);
-        let min = self.center - delt;
-        let max = self.center + delt;
-        AABB::with_bounds(min, max)
-    }
-}
-
 impl Shape for Sphere {
     fn intersect(&self, ray: &Ray) -> Option<f32> {
         use std::mem;
@@ -91,6 +82,13 @@ impl Shape for Sphere {
             0.5 + (point.y - self.center.y) / (2. * self.radius),
         )
     }
+
+    fn aabb(&self) -> AABB {
+        let delt = Vector::new(self.radius, self.radius, self.radius);
+        let min = self.center - delt;
+        let max = self.center + delt;
+        AABB::with_bounds(min, max)
+    }
 }
 
 #[cfg(test)]

src/shape/triangle.rs

@@ -1,11 +1,11 @@
 use super::Shape;
 use crate::{Point, Point2D, Vector};
-use bvh::aabb::{Bounded, AABB};
+use bvh::aabb::AABB;
 use bvh::ray::Ray;
 use serde::{Deserialize, Deserializer};
 
 /// Represent a triangle inside the scene.
-#[derive(Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct Triangle {
     c0: Point,
     c0c1: Vector,
@@ -40,15 +40,6 @@ impl Triangle {
     }
 }
 
-impl Bounded for Triangle {
-    fn aabb(&self) -> AABB {
-        AABB::empty()
-            .grow(&self.c0)
-            .grow(&(self.c0 + self.c0c1))
-            .grow(&(self.c0 + self.c0c2))
-    }
-}
-
 impl Shape for Triangle {
     fn intersect(&self, ray: &Ray) -> Option<f32> {
         let pvec = ray.direction.cross(&self.c0c2);
@@ -88,6 +79,13 @@ impl Shape for Triangle {
     fn project_texel(&self, point: &Point) -> Point2D {
         self.barycentric(point)
     }
+
+    fn aabb(&self) -> AABB {
+        AABB::empty()
+            .grow(&self.c0)
+            .grow(&(self.c0 + self.c0c1))
+            .grow(&(self.c0 + self.c0c2))
+    }
 }
 
 #[derive(Debug, Deserialize)]

src/texture/mod.rs

@@ -1,7 +1,15 @@
 use super::core::LinearColor;
 use super::Point2D;
 
+/// All the existing `Texture` implementation.
+#[enum_dispatch::enum_dispatch]
+#[derive(Debug, PartialEq)]
+pub enum TextureEnum {
+    UniformTexture,
+}
+
 /// Represent an object's texture.
+#[enum_dispatch::enum_dispatch(TextureEnum)]
 pub trait Texture: std::fmt::Debug {
     /// Get the color at a given texel coordinate
     fn texel_color(&self, point: Point2D) -> LinearColor;

src/texture/uniform.rs

@@ -4,7 +4,7 @@ use crate::Point2D;
 use serde::Deserialize;
 
 /// A texture with the same color on all points.
-#[derive(Debug, PartialEq, Deserialize)]
+#[derive(Clone, Debug, PartialEq, Deserialize)]
 pub struct UniformTexture {
     color: LinearColor,
 }