Adaptive depth bias for soft shadows

Abstract

With shadow mapping the need of a suitable biasing technique due to shadow aliasing is indisputable. Dou et al. [Dou14] introduced a biasing technique that computes the optimal bias adaptively for each fragment. In this paper, we propose enhancements for this algorithm. First, we extend the algorithm for soft shadows, such as percentage closer filtering (PCF) and percentage closer soft shadows (PCSS). Second, we minimize the projective aliasing by introducing a scale factor depending on the ratio between surface and light direction. We show that our enhancements increase the shadow quality and introduce only a small overhead.