Implement Light

[ehud-gordon]

Implement:

• Add light source (type: point / parallel).
• struct fragment{};
• class LightSource
• virtual vector<fragment> getShadingForFragment(face, fragment[x, y, w0, w1, w2], material)
class ParallelLightSource : LightSource
• vec3 direction; // defined like gaze in camera
class PointLightSource : LightSource
• vec3 location; // defined like eye in camera
• Add Ambient Light to scene, allow user to control it.
• class AmbientLightSource : LightSource
• float intensity;