Fixed camera

src/raytracer.rs

@@ -13,13 +13,12 @@ pub fn phong_shade_point(scene: &Scene, intersect: &Intersection) -> Vector3<u8>
         material,
         ..
     } = intersect;
-    let ambient_light = &scene.ambient_light;
     let kd = material.kd;
     let ks = material.ks;
     let shininess = material.shininess;
 
     // Compute the ambient light component and set it as base colour
-    let mut colour = kd.component_mul(ambient_light);
+    let mut colour = ZERO_VECTOR;
 
     for light in &scene.lights {
         let Light {
@@ -28,42 +27,36 @@ pub fn phong_shade_point(scene: &Scene, intersect: &Intersection) -> Vector3<u8>
             falloff: light_falloff,
         } = light;
 
-        // Compute light incidence vector and its distance
+        // Point to light
         let to_light = light_position - point;
         let light_distance = to_light.norm();
-        let light_incidence = Unit::new_normalize(to_light);
+        let to_light = Unit::new_normalize(to_light);
+        // Point to camera
+        let to_camera = Unit::new_normalize(-incidence.into_inner());
+        // Diffuse component
+        let n_dot_l = normal.dot(&to_light).max(0.0);
+        let diffuse = n_dot_l * kd;
+        // Specular component
+        let mut specular = ZERO_VECTOR;
+        if n_dot_l > 0.0 {
+            // Halfway vector.
+            let h = Unit::new_normalize(to_camera.lerp(&to_light, 0.5));
+            let n_dot_h = normal.dot(&h).max(0.0);
+            specular = ks * n_dot_h.powf(shininess);
+        }
 
         // Compute light falloff
         let falloff = 1.0
-            / (light_falloff[0]
+            / (1.0
+                + light_falloff[0]
                 + light_falloff[1] * light_distance
-                + light_falloff[2] * light_distance * light_distance);
+                + light_falloff[2] * light_distance.powi(2));
 
-        // Compute diffuse
-        let n_dot_l = normal.dot(&light_incidence);
-        let diffuse = if n_dot_l > 0.0 {
-            kd * n_dot_l
-        } else {
-            ZERO_VECTOR
-        };
-
-        // Compute specular
-        let h = (&light_incidence.into_inner() + incidence.into_inner()).normalize();
-        let n_dot_h = normal.dot(&h);
-        let specular = if n_dot_h > 0.0 {
-            ks * n_dot_h.powf(shininess)
-        } else {
-            ZERO_VECTOR
-        };
-
-        // Update colour with diffuse and specular components
-        colour += light_colour.component_mul(&((diffuse + specular) * falloff));
+        let light_intensity = light_colour.component_mul(&(diffuse + specular)) * falloff;
+        colour += &light_intensity;
     }
 
-    // Clamp colour values to [0, 255] and convert to u8
-    let r = nalgebra::clamp(colour.x * 255.0, 0.0, 255.0) as u8;
-    let g = nalgebra::clamp(colour.y * 255.0, 0.0, 255.0) as u8;
-    let b = nalgebra::clamp(colour.z * 255.0, 0.0, 255.0) as u8;
-
+    colour *= 255.0;
+    let (r, g, b) = (colour.x as u8, colour.y as u8, colour.z as u8);
     Vector3::new(r, g, b)
 }