Fullsphere Irradiance Factorization for Real-Time All-Frequency Illumination for Dynamic Scenes

Abstract

Computation of illumination with soft-shadows from all-frequency environment maps, is a computationally expensive process. Use of pre-computation add the limitation that receiver's geometry must be known in advance, since Irradiance computation takes into account the receiver's normal direction. We propose a method that using a new notion that we introduce, the Fullsphere Irradiance, allows us to accumulate the contribution from all light sources in the scene, on a possible receiver without knowing the receiver's geometry. This expensive computation is done in a pre-processing step. The pre-computed value is used at run time to compute the Irradiance arriving at any receiver with known direction. We show how using this technique we compute soft-shadows and self-shadows in real-time from all-frequency environments, with only modest memory requirements. A GPU implementation of the method, yields high frame rates even for complex scenes with dozens of dynamic occluders and receivers.