Allfrequency relighting of glossy objects

We present a technique for interactive rendering of glossy objects in all-frequency lighting environments that captures shadows and interreflections. Our technique is based on precomputed radiance transfer and separable BRDF approximation. In the preprocessing step, we factor glossy BRDFs using separable decomposition and keep only a few low-order approximation terms, consisting of purely view-dependent and light-dependent components. At each vertex, we sample the visibility and precompute a direct illumination transport vector corresponding to each BRDF term, then compress the data with a non-linear wavelet approximation. We use programmable graphics hardware to accelerate this step. The direct illumination pass is followed by interreflection passes, each of which gathers compressed transport vectors from the previous pass to produce global illumination transport vectors. During rendering, we dynamically sample the lighting and apply a wavelet transform to produce a light vector. We compute the inner products of the light vector with the precomputed transport vectors, and the results are combined with the view-dependent components of the BRDF to produce vertex colors. We describe accelerating the rendering using programmable graphics hardware, and discuss the limitations and tradeoffs imposed by the hardware