Spherical Piecewise Constant Basis Functions for All-Frequency Precomputed Radiance Transfer

This paper presents a novel basis function, called spherical piecewise constant basis function (SPCBF), for precomputed radiance transfer. SPCBFs have several desirable properties: rotatability, ability to represent all-frequency signals, and support for efficient multiple product. By smartly partitioning the illumination sphere into a set of subregions, and associating each subregion with an SPCBF valued 1 inside the region and 0 elsewhere, we precompute the light coefficients using the resulting SPCBFs. Efficient rotation of the light representation in SPCBFs is achieved by rotating the domain of SPCBFs. During run-time rendering, we approximate the BRDF and visibility coefficients using the set of SPCBFs for light, possibly rotated, through fast lookup of summed-area-table (SAT) and visibility distance table (VDT), respectively. SPCBFs enable new effects such as object rotation in all-frequency rendering of dynamic scenes and onthe-fly BRDF editing under rotating environment lightin...

• Type: Journal
• Year: 2008
• Where: TVCG
• Authors: Kun Xu, Yun-Tao Jia, Hongbo Fu, Shi-Min Hu, Chiew-Lan Tai
• Keywords: Basis Function, Constant Basis Function, Precomputed Radiance Transfer, TVCG 2008