high performance computing on graphics processing units: hgpu.org

This paper presents a real-time soft shadow rendering algorithm based on the shadow-mapping technique. The key idea of this algorithm is to use only a single shadow map for a flat extended light source. The algorithm also uses the single shadow map to discretize the occluders to many flat patches which are parallel with the light source. Finally, these patches are used to compute the percentage of visibility between a scene point and the light source, and then produce the soft shadow modulation factors buffer (smfb). The algorithm is implemented with multi-passes rendering method in the graphic-process-unit (GPU) fully, dose not need any pre-computation, and can adapt to the dynamic scene.