Figure 3: A reflective cube on a diffuse plane. Left image shows the scene without caustics, the middle image shows the scene with a simple screen space method for caustics, and the right image shows the full lighting solution that includes both the caustics and the reflection of the caustics in the cube.
Figure 4: Progressive photon mapping is the first algorithm capable of rendering global illumination in complex scenes. It works by combining multiple passes, where each pass consists of emitting photons from the light source into the scene and rendering an image leveraging the photon map.
