Real-time rendering of approximate caustics under environment illumination

We present a real-time GPU caustics rendering technique for dynamic scenes under environment illumination taking into account light occlusion. The dynamic scenes consist of caustic objects (reflective and/or refractive objects which produce caustics) and receiver objects (non-reflective and nonrefractive), that can be translated and rotated. As the light source, we consider environment illumination (distant lights from all directions) which we approximate as a set of important directional lights. Our rendering technique is able to generate approximate caustics cast on receiver objects as well as volumetric caustics. As the preprocessing, we precompute the caustic patterns of caustic objects for several directional lights and store them in caustic images. During the rendering, we interpolate the precomputed caustic patterns based on the important directional lights which approximate the given environment illumination. The important directional lights are obtained by using our proposed environment cube map segmentation technique. Our proposed technique is able to generate real-time caustics which are visually similar to the caustic generated by using a commercial renderer mental ray.