language: en

A Ray Tracing Method for Illumination Calculation in Diffuse-Specular Scenes

Peter Shirley
Department of Computer Science University of Illinois
1304 West Springfield Avenue Urbana, Illinois 61801 USA

Abstract Several ways of improving the realism of the results of traditional ray tracing are presented. The essential physical quantities of spectral radiant power and spectral radiance and their use in lighting calculations are discussed. Global illumination terms are derived by employing illumination ray tracing for calculation of quickly changing indirect lighting components, and ra-diosity ray tracing for slowly changing indirect lighting components. Direct lighting is calculated during the viewing phase allowing the use of bump maps. Finally, a method is introduced that reduces the total number of shadow rays to no more than the total number of viewing rays for a given picture.

Keywords: Bump Mapping, Illumination, Radiosity, Radiance, Ray Tracing, Realism, Stratified Sampling, Texture Mapping.

1 Introduction