Dynamic Radiosity using Higher Order Functions Bases and Temporal Coherence

Venceslas BIRI
University of Marne-la-Vallée
Department of Computer Graphics
F-77700 Serris
FRANCE

Keywords:Dynamic Radiosity, Animation, Temporal Coherence

Abstract

The computation of global illumination in a dynamic scene constitutes a real challenge in computer graphics. In radiosity algorithms, this problem is far from being easy, especially when light sources move in a complex scene. This subject becoming more and more widespread, many algorithms have been presented to solve the dynamic radiosity problem. Unfortunately, none uses intensive temporal coherence and few are efficient when dealing with a moving light source. This paper introduces a new algorithm that computes animations with any moving surfaces - even light sources. We take into account the temporal coherence between two frames to determine only the luminous energy differences between the previous global illumination solution and the new one. A mathematical development of the form factor for a translation or a rotation avoids unnecessary form factors computations. This new approach leads to an efficient and simple algorithm, similar to the classical progressive refinement method. Thus, it is able to compute the global illumination of animations at least twice faster than the classical approach.