Dynamic Per Object Ray Caching Textures for Real-Time Ray Tracing

Ray tracing allows the rendering of scenes with very complex light interactions. It is based on the idea that reflection, refraction and shadows can be modeled by recursively following the path that light takes as it bounces through an environment. However, despite its conceptual simplicity, tracing rays is a computationally intensive task. Also, optimizing memory management to increase efficiency is hard since coherent access in 3D space would not generate coalescent memory patterns. We present a new caching-like strategy suitable for real-time ray tracing which is capable to store data generated in previous frames in such a way that coherent memory access is achieved while data is reused by subsequent frames. By storing light bounce results of previously traced rays in a cube map attached to each scene object, we show that it is possible to explore the efficient memory sampling mechanism provided by the graphics hardware to increase frame rate. Our approach is suitable for static scenes and may prevent deep interactions of rays with the scene as well as enable synchronous computation of rays in parallelized architectures, and it can be easily integrated to any existing ray tracing solutions.