Adds concept of distance to illumination

light/ambientlight.cpp

@@ -1,5 +1,5 @@
 #include "light/ambientlight.h"
 
 Light::Illumination AmbientLight::illuminate(Scene const &scene, Ray const &ray) const {
-  return {this->color * this->intensity, -ray.normal};
+  return {this->color * this->intensity, -ray.normal, 0};
 }

light/light.h

@@ -13,6 +13,7 @@ public:
   struct Illumination {
     Color color;
     Vector3d direction;
+    float distance;
   };
 
   // Constructor / Destructor

light/pointlight.cpp

@@ -12,6 +12,7 @@ Light::Illumination PointLight::illuminate(Scene const &scene, Ray const &ray) c
 
   // Precompute the distance from the light source
   float const distance = length(target - this->position);
+  illum.distance = distance;
 
   // Define a secondary ray from the surface point to the light source.
   Ray lightRay;

light/spotlight.cpp

@@ -13,6 +13,7 @@ Light::Illumination SpotLight::illuminate(Scene const &scene, Ray const &ray) co
 
   // Precompute the distance from the light source
   float const distance = length(target - this->position);
+  illum.distance = distance;
 
   // Define a secondary ray from the surface point to the light source
   Ray lightRay;

light/sunlight.cpp

@@ -12,6 +12,7 @@ Light::Illumination SunLight::illuminate(Scene const &scene, Ray const &ray) con
     // Illumination object
     Illumination illum;
     illum.direction = this->direction;
+    illum.distance = INFINITY;
 
     // Define a secondary ray from the surface point to the light source.
     Ray lightRay;