Real-time soft shadows using a single light sample

Abstract

We present a real-time rendering algorithm that generates soft shadows of dynamic scenes using a single light \nsample. As a depth-map algorithm it can handle arbitrary shadowed surfaces. The shadow-casting surfaces, \nhowever, should satisfy a few geometric properties to prevent artifacts. Our algorithm is based on a bivariate \nattenuation function, whose result modulates the intensity of a light causing shadows. The first argument specifies \nthe distance of the occluding point to the shadowed point; the second argument measures how deep the shadowed \npoint is inside the shadow. The attenuation function can be implemented using dependent texture accesses; the \ncomplete implementation of the algorithm can be accelerated by today's graphics hardware. We outline the \nimplementation, and discuss details of artifact prevention and filtering.