Using A-buffer in radiosity

Anti-aliasing in form factor computation and precise determination of shadow boundaries are important issues for radiosity method. A-buffer is a technique introduced by L. Carpenter (1984) for anti-aliasing in hidden surface removal. In this paper, we propose a method based on the A-buffer to replace the Z-buffer in the computation of form factors using the Hemicube for anti-aliasing. The method directly computes shadow boundaries in contrast to the adaptive re-meshing approach. Though the processing of shadow boundaries is not fast, only one discontinuity meshing (no iteration) is required. We implement the method in an infrastructure building design system