Radiance transfer biclustering for real-time all-frequency biscale rendering

We present a real-time algorithm to render all-frequency radiance transfer at both macroscale and mesoscale. At a mesoscale, the shading is computed on a per-pixel basis by integrating the product of the local incident radiance and a bidirectional texture function. While at a macroscale, the precomputed transfer matrix, which transfers the global incident radiance to the local incident radiance at each vertex, is losslessly compressed by a novel biclustering technique. The biclustering is directly applied on the radiance transfer represented in a pixel basis, on which the BTF is naturally defined. It exploits the coherence in the transfer matrix and a property of matrix element values to reduce both storage and runtime computation cost. Our new algorithm renders at real-time frame rates realistic materials and shadows under all-frequency direct environment lighting. Comparisons show that our algorithm is able to generate images that compare favorably with reference ray tracing results, and has obvious advantages over alternative methods in storage and preprocessing time.