IMPROVING GLOBAL ILLUMINATION WITH A-BUFFER TECHNIQUE

Abstract

Two of the main issues m radiosity generated images are efficient form factor computation and proper mesh generation. Although hemicube algorithm remains a simple and fast method for radiosity form factor computation, its simple sampling scheme for the hemicube pixels causes unacceptable accuracy in its result. We improve the accuracy by applying the A-buffer anti-aliasing technique to handle the hemicube visibility and aliasing, thereby alleviating this inaccuracy that was originally caused by the under/over estimation of the projections on the hemicube pixels. An appropriate meshing scheme, based on the inherent data structure of the A-buffer algorithm, provides better shading and eliminates light leaks around shadow boundaries. The final radiosity solution incorporating these two features is implemented with the progressive refinement approach to improve interactivity.