All-Frequency Precomputed Radiance Transfer for Glossy Objects

We introduce a method based on precomputed radiance transfer (PRT) that allows interactive rendering of glossy surfaces and includes shadowing effects from dynamic, “all-frequency” lighting. Specifically, source lighting is represented by a cube map at resolution nL = 6 × 32 × 32. We present a novel PRT formulation which factors glossy BRDFs into purely view-dependent and light-dependent parts, achieving reasonable accuracy with only m=10 dimensional factors. We then tabulate an m × nL transfer matrix at each surface vertex as a preprocess, representing the object’s response to this lighting. Because this surface signal is so high-dimensional, reducing m is crucial for making practical both the preprocessing and run-time. To compress the transfer matrices, we divide the cube map into 24 lighting segments and apply the Haar wavelet basis in each segment to provide sensible quantization. We also apply clustered principal component analysis (CPCA) to each PRT segment to approxi...

• Type: Conference
• Year: 2004
• Where: RT
• Authors: Xinguo Liu, Peter-Pike J. Sloan, Heung-Yeung Shum, John Snyder
• Keywords: Cube Map, Lighting, RT 2004, Transfer Matrices