Variance soft shadow mapping

Abstract

Variance shadow map (VSM) [Donnelly and Lauritzen 2006] is a kind of pre-filtering-based hard shadow mapping method, which achieves both good anti-aliasing quality and high performance. However, soft shadow rendering relying on VSM is non-trivial and remains unsolved. Motivated by it, we propose variance soft shadow mapping (VSSM) method for rendering plausible soft shadow, which is based on the theoretical framework of percentagecloser soft shadows (PCSS) [Fernando 2005].