Volumetric Shadow Mapping

Gautron pascal, Marvie Jean-Eudes, François Guillaume

Abstract

Our approach builds upon two unrelated rendering techniques: the well-known shadow mapping algorithm [Williams 1978] and sub-surface texture mapping [Francois et al. 2008] for real-time scattering simulation in multilayered materials defined by 2D textures. We simulate single scattering by evenly sampling the 2D light space to reduce aliasing artifacts due to undersampling of the shadow map. The design of volumetric lighting commonly features gobo textures to aesthetically control the light shaft effects. The ray marching in the 2D light space uniformly samples such textures, hence preserving the gobo details which are unlikely to be preserved when sampling the camera ray in world space