Instant caching for interactive global Iilumination

The ability to interactively render dynamic scenes with global illumination is one of the main challenges in computer graphics. The improvement in performance of interactive ray tracing brought about by significant advances in hardware and careful exploitation of coherence has rendered the potential of interactive global illumination a reality. However, the simulation of complex light transport phenomena, such as diffuse interreflections, is still quite costly to compute in real time. In this paper we present a caching scheme, termed Instant Caching, based on a combination of irradiance caching and instant radiosity. By reutilising calculations from neighbouring computations this results in a speedup over previous instant radiosity-based approaches. Additionally, temporal coherence is exploited by identifying which computations have been invalidated due to geometric transformations and updating only those paths. The exploitation of spatial and temporal coherence allows us to achieve superior frame rates for interactive global illumination within dynamic scenes, without any precomputation or quality loss when compared to previous methods; handling of lighting and material changes are also demonstrated.We thank Greg Ward for the Office and Conference scenes from Radiance package, Marko Dabrovic for the Sibenik cathedral model. Finally, we thank Stanford's Graphics Group for the Bunny model from the Stanford 3D Repository. We would like to thank Kadi Bouatouch for insightful comments on the document. This research was partially funded PT-FCT grant PTDC/EIA/65965/2006 (IGIDE project) and UK-EPSRC grant EP/D069874/2