Photon streaming for interactive global illumination in dynamic scenes

摘要

While many methods exist for simulating diffuse light inter-reflections, relatively few of them are adapted to dynamic scenes. Despite approximations made on the formal rendering equation, managing dynamic environments at interactive or real-time frame rates still remains one of the most challenging problems. This paper presents a lighting simulation system based on photon streaming, performed continuously on the central processor unit. The power corresponding to each photon impact is accumulated onto predefined points, called virtual light accumulators (or VLA). VLA are used during the rendering phase as virtual light sources. We also introduce a priority management system that automatically adapts to brutal changes during lighting simulation (for instance due to visibility changes or fast object motion). Our system naturally benefits from multi-core architecture. The rendering process is performed in real time using a graphics processor unit, independently from the lighting simulation process. As shown in the results, our method provides high framerates for dy namic scenes, with moving viewpoint, objects and light sources.