Reflective shadow maps

Abstract

In this paper we present "reflective shadow maps", an algorithm for interactive rendering of plausible indirect illumination. A reflective shadow map is an extension to a standard shadow map, where every pixel is considered as an indirect light source. The illumination due to these indirect lights is evaluated on-the-fly using adaptive sampling in a fragment shader. By using screen-space interpolation of the indirect lighting, we achieve interactive rates, even for complex scenes. Since we mainly work in screen space, the additional effort is largely independent of scene complexity. The resulting indirect light is approximate, but leads to plausible results and is suited for dynamic scenes. We describe an implementation on current graphics hardware and show results achieved with our approach. © 2005 ACM.