Fast Massively Parallel Progressive Radiosity on the MP-1

Radiosity is a powerful method for solving the global illumination problem in the case of purely diffuse light reflexions. The progressive refinement algorithm provides interactivity during computation by displaying intermediate images, and overshooting methods increases the convergence rate of progressive radiosity. However, computation times remain very important. Parallelising these algorithms is a good way to significantly improve interactivity by reducing computation time. The aim of this paper is to present a method for the parallelisation of the progressive refinement radiosity algorithm on a massively parallel SIMD machine. We took care of both the SIMD machine nature and the high number of available processors on studying the several ways to efficiently implement the algorithm. The parallel scheme we propose uses a disk projection area for form factors estimate and decreases dramatically the computation times. Keyword.s: Progressive radiosity; Form factor calculation; Parallel rendering