added refraction computations to Scene::traceRay()

git-svn-id: svn://anubis/fart/trunk@376 7f9b0f55-74a9-4bce-be96-3c2cd072584d

main/Scene.cc

@@ -119,13 +119,15 @@ void Scene::renderPixel(int x, int y, unsigned char * pixel)
 
 Color Scene::traceRay(const Ray & ray)
 {
-    return traceRayRecurse(ray, m_max_depth, 1.0);
+    static refptr<Material> air = new Material();
+    return traceRayRecurse(ray, m_max_depth, 1.0, air);
 }
 
 /**
  * factor: the proportion of the final color that this computation is worth
  */
-Color Scene::traceRayRecurse(const Ray & ray, int depth, double factor)
+Color Scene::traceRayRecurse(const Ray & ray, int depth, double factor,
+        refptr<Material> last_material)
 {
     Color color;
 
@@ -161,7 +163,8 @@ Color Scene::traceRayRecurse(const Ray & ray, int depth, double factor)
                 Ray jitterNewRay(jitter_surface_point, reflected_direction);
                 Color c = traceRayRecurse(jitterNewRay,
                                           depth - 1,
-                                          factor * reflectance);
+                                          factor * reflectance,
+                                          material);
                 color += c * reflectance;
             }
 
@@ -171,10 +174,15 @@ Color Scene::traceRayRecurse(const Ray & ray, int depth, double factor)
                 color *= (1.0 - transparency);
                 Vector jitter_surface_point = hit.position
                                               + ray.getDirection() * 0.0001;
-                Ray newRay(jitter_surface_point, ray.getDirection());
+                Vector refracted_direction =
+                    ray.getDirection().refract(hit.normal,
+                            last_material->getRefraction(),
+                            material->getRefraction());
+                Ray newRay(jitter_surface_point, refracted_direction);
                 Color c = traceRayRecurse(newRay,
                                           depth - 1,
-                                          factor * transparency);
+                                          factor * transparency,
+                                          material);
                 color += c * transparency;
             }
         }

main/Scene.h

@@ -46,7 +46,8 @@ class Scene
     protected:
         /* private methods */
         Color traceRay(const Ray & ray);
-        Color traceRayRecurse(const Ray & ray, int depth, double factor);
+        Color traceRayRecurse(const Ray & ray, int depth, double factor,
+                refptr<Material> last_material);
         Shape::Intersection getRayClosestHit(const Ray & ray);
         Color computePhong(const refptr<Material> material,
                            const Ray & viewRay,