(ACM Siggraph, 2015) Widmer, S.; Pajak, D.; Schulz, A.; Pulli, K.; Kautz, J.; Goesele, M.; Luebke, D.; Petrik Clarberg and Elmar Eisemann
We propose an efficient acceleration structure for real-time screenspace ray tracing. The hybrid data structure represents the scene geometry by combining a bounding volume hierarchy with local planar approximations. This enables fast empty space skipping while tracing and yields exact intersection points for the planar approximation. In combination with an occlusion-aware ray traversal our algorithm is capable to quickly trace even multiple depth layers. Compared to prior work, our technique improves the accuracy of the results, is more general, and allows for advanced image transformations, as all pixels can cast rays to arbitrary directions. We demonstrate real-time performance for several applications, including depth-of-field rendering, stereo warping, and screen-space ray traced reflections.