Kasper Høy Nielsen, Niels Jørgen Christensen

Informatics and Mathematical Modelling

The Technical University of Denmark

DK 2800 Lyngby, Denmark

{khn,njc}@imm.dtu.dk

**ABSTRACT**

This paper describes a method for dynamic changing of colours and intensities of light sources in a radiosity-lit environment. We introduce a fast radiosity sampling approach where energy is sorted with respect to the emitting lights. The idea is to tag energy with a light source identifier in order to determine from which light source energy is coming from, either directly or indirectly. Based on this information the subsequent reconstruction allows for interactive changing of light source emissions, as long as the geometry in the environment remains static. We illustrate this concept by developing a modified progressive refinement algorithm that performs efficient concurrent sampling of separate light source solutions. We show that the result is useful for real-time animation of realistic lighting in virtual environments. Furthermore, we describe how the method can be adapted to handle near real-time animation of moving lights.