GPU Gems 2: Programming Techniques for High-Performance Graphics and General-Purpose Computation

Chapter 10. Real-Time Computation of Dynamic Irradiance Environment Maps

Gary KingNVIDIA Corporation

Environment maps are a popular image-based rendering technique, used to represent spatially invariant ^[1] spherical functions. This chapter describes a fully GPU-accelerated method for generating one particularly graphically interesting type of environment map, irradiance environment maps, using DirectX Pixel Shader 3.0 and floating-point texturing. This technique enables applications to quickly approximate complex global lighting effects in dynamic environments (such as radiosity from dynamic lights and dynamic objects). For brevity, this chapter assumes that the reader has working knowledge of environment maps, particularly cube maps (Voorhies ...