Added experimental mirrorshader

shader/mirrorshader.cpp

@@ -4,9 +4,9 @@
 MirrorShader::MirrorShader() {}
 
 Color MirrorShader::shade(Scene const &scene, Ray const &ray) const {
-  // IMPLEMENT ME
-  // Calculate the reflection vector
-  // Create a new reflection ray
-  // Send the new ray out into the scene and return the result
-  return Color(0, 0, 1);
+    Vector3d newDirection = ray.direction - 2 * dotProduct(ray.normal, ray.direction) * ray.normal;
+
+    //TODO: should we reset the ray or use a new ray? Regarding the count of bounces
+    Ray mirroredRay = Ray(ray.origin + ray.length * ray.direction, newDirection);
+    return scene.traceRay(mirroredRay);
 }