Authors
Paul Green, Jan Kautz, Fr
Massachusetts Institute of Technology, Computer Science and Artificial Intelligence Laboratory; University College London
Portals
Abstract
We present a technique for approximating isotropic BRDFs and precomputed self-occlusion that enables accurate and efficient prefiltered environment map rendering. Our approach uses a nonlinear approximation of the BRDF as a weighted sum of isotropic Gaussian functions. Our representation requires a minimal amount of storage, can accurately represent BRDFs of arbitrary sharpness, and is above all, efficient to render. We precompute visibility due to self-occlusion and store a low-frequency approximation suitable for glossy reflections. We demonstrate our method by fitting our representation to measured BRDF data, yielding high visual quality at real-time frame rates.
Contribution
- We introduce an isotropic BRDF representation that accurately fits measured BRDF data and requires very little storage
- Our representation is ideal for integration with prefiltered environment maps, enabling high-frequency reflections at real-time rates, evaluated entirely on the GPU
- We introduce a light-weight visibility approximation for shadowed reflections, where only large-scale accuracy is important for visually realistic renderings