Hardware-accelerated global illumination by image space photon mapping
- 1 August 2009
- conference paper
- conference paper
- Published by Association for Computing Machinery (ACM)
Abstract
We describe an extension to photon mapping that recasts the most expensive steps of the algorithm -- the initial and final photon bounces -- as image-space operations amenable to GPU acceleration. This enables global illumination for real-time applications as well as accelerating it for offline rendering. Image Space Photon Mapping (ISPM) rasterizes a light-space bounce map of emitted photons surviving initial-bounce Russian roulette sampling on a GPU. It then traces photons conventionally on the CPU. Traditional photon mapping estimates final radiance by gathering photons from a k-d tree. ISPM instead scatters indirect illumination by rasterizing an array of photon volumes. Each volume bounds a filter kernel based on the a priori probability density of each photon path. These two steps exploit the fact that initial path segments from point lights and final ones into a pinhole camera each have a common center of projection. An optional step uses joint bilateral upsampling of irradiance to reduce the fill requirements of rasterizing photon volumes. ISPM preserves the accurate and physically-based nature of photon mapping, supports arbitrary BSDFs, and captures both high- and low-frequency illumination effects such as caustics and diffuse color interreflection. An implementation on a consumer GPU and 8-core CPU renders highquality global illumination at up to 26 Hz at HD (1920x1080) resolution, for complex scenes containing moving objects and lights.Keywords
This publication has 23 references indexed in Scilit:
- Adaptive Caustic Maps Using Deferred ShadingComputer Graphics Forum, 2009
- Imperfect shadow maps for efficient computation of indirect illuminationACM Transactions on Graphics, 2008
- Real-time KD-tree construction on graphics hardwareACM Transactions on Graphics, 2008
- Reducing Noise in Image-Space Caustics with Variable-Sized SplattingJournal of Graphics Tools, 2008
- Stackless KD‐Tree Traversal for High Performance GPU Ray TracingComputer Graphics Forum, 2007
- Implicit visibility and antiradiance for interactive global illuminationACM Transactions on Graphics, 2007
- Multi-level ray tracing algorithmACM Transactions on Graphics, 2005
- Interactive Rendering with Coherent Ray TracingComputer Graphics Forum, 2001
- Comprehensible rendering of 3-D shapesACM SIGGRAPH Computer Graphics, 1990
- An improved illumination model for shaded displayCommunications of the ACM, 1980