Add diffuse strength term to LambertianMaterial

src/camera.rs

@@ -87,8 +87,8 @@ pub fn partial_render_scene<T: RealField>(
         scene.camera_location,
     );
     let ambient_intensity: T = convert(0.0);
-    let directional_intensity1: T = convert(0.7);
+    let directional_intensity1: T = convert(7.0);
-    let directional_intensity2: T = convert(0.3);
+    let directional_intensity2: T = convert(3.0);
     let integrator = WhittedIntegrator::<T> {
         ambient_light: ColourRgbF::from_named(NamedColour::White) * ambient_intensity,
         lights: vec![

src/main.rs

@@ -66,6 +66,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                 -2.0,
                 Rc::new(LambertianMaterial {
                     colour: ColourRgbF::new(0.55, 0.27, 0.04),
+                    diffuse_strength: 0.1,
                 }),
             )),
             Box::new(Sphere::new(
@@ -73,6 +74,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                 1.0,
                 Rc::new(LambertianMaterial {
                     colour: ColourRgbF::from_named(NamedColour::Green),
+                    diffuse_strength: 0.1,
                 }),
             )),
             Box::new(Sphere::new(
@@ -80,6 +82,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                 1.0,
                 Rc::new(LambertianMaterial {
                     colour: ColourRgbF::from_named(NamedColour::Blue),
+                    diffuse_strength: 0.1,
                 }),
             )),
             Box::new(Sphere::new(
@@ -87,6 +90,7 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                 1.0,
                 Rc::new(LambertianMaterial {
                     colour: ColourRgbF::from_named(NamedColour::Red),
+                    diffuse_strength: 0.1,
                 }),
             )),
         ],

src/materials.rs

@@ -13,12 +13,14 @@ pub trait Material<T: RealField>: Debug {
 #[derive(Debug)]
 pub struct LambertianMaterial<T: RealField> {
     pub colour: ColourRgbF<T>,
+    pub diffuse_strength: T,
 }
 
 impl<T: RealField> LambertianMaterial<T> {
     pub fn new_dummy() -> LambertianMaterial<T> {
         LambertianMaterial {
             colour: ColourRgbF::new(T::one(), T::one(), T::one()),
+            diffuse_strength: T::one(),
         }
     }
 }
@@ -29,7 +31,7 @@ impl<T: RealField> Material<T> for LambertianMaterial<T> {
     ) -> Box<dyn Fn(Vector3<T>, Vector3<T>, ColourRgbF<T>) -> ColourRgbF<T> + 'a> {
         Box::new(
             move |_w_o: Vector3<T>, _w_i: Vector3<T>, colour_in: ColourRgbF<T>| {
-                self.colour * colour_in
+                self.colour * colour_in * self.diffuse_strength
             },
         )
     }