A Gentle Introduction to Precomputed Radiance Transfer

Realistic image synthesis is one of the most relevant subjects in computer graphics, and many algorithms have been developed to try to reproduce the visual complexity perceived in the real world. However, rendering realistic images in real time remains a challenge even with the support of modern graphics hardware. Precomputed Radiance Transfer (PRT) is a new graphics technique capable of synthesizing highly realistic images in real time. This is achieved by restricting the solution of the rendering equation to a subset of the light transport paths that handle only energy exchange among diffuse surfaces. Due to the quality of its results, PRT has attracted the attention of many computer graphics researchers and practitioners. However, understanding and implementing PRT requires familiarity with concepts such as projection into basis functions, empirical function integration and light transport theory. This tutorial provides a gentle introduction to PRT and its required background, enabling the readers to understand and implement the technique.