Figure 1: An illuminated fabric with an acquired anisotropic velvet (left), isotropic wood (middle) and shiny plastic (right) BRDF rendered at 40 FPS (512 × 512) using our wavelet encoding. The initial data sets containing 32 4 RGB samples (12MB) are compressed into 3D textures of 700KB. Our approach can be combined with classical texture, environment and bump mapping in order to produce high quality local illumination. Acquired data often provides the best knowledge of a material's bidirectional reflectance distribution function (BRDF). Its integration into most real-time rendering systems requires both data compression and the implementation of the decompression and filtering stages on contemporary graphics processing units (GPUs). This paper improves the quality of real-time per-pixel lighting on GPUs using a wavelet decomposition of acquired BRDFs. Threedimensional texture mapping with indexing allows us to efficiently compress the BRDF data by exploiting much of the coherency between hemispherical data. We apply built-in hardware filtering and pixel shader flexibility to perform filtering in the full 4D BRDF domain. Anti-aliasing of specular highlights is performed via a progressive level-of-detail technique built upon the multiresolution of the wavelet encoding. This technique increases rendering performance on distant surfaces while maintaining accurate appearance of close ones.
REF ] provides real time rendering of acquired data using the sparsity of a wavelet representation and low rank of the reflection operator.
Wavelet encoding of BRDFs for real-time rendering
GI '07
Computer Science