A virtual light field approach to global illumination

Abstract

This paper describes an algorithm that provides real-time walkthrough for globally illuminated scenes that contain mixtures of ideal diffuse and specular surfaces. A type of light field data structure is used for propagating radiance outward from light emitters through the scene, accounting for any kind of L(S\D)* light path. The light field employed is constructed by choosing a regular point subdivision over a hemisphere, to give a set of directions, and then corresponding to each direction there is a rectangular grid of parallel rays. Each rectangular grid of rays is further subdivided into rectangular tiles, such that each tile references a sequence of 2D images containing colour values corresponding to the outgoing radiances of surfaces intersected by the rays in that tile. This structure is then used for final image rendering. Propagation times can be very long and the memory requirements very high. This algorithm, however, offers a global illumination solution for real-time walkthrough even on a single processor