Incremental Instant Radiosity for Real-Time Indirect Illumination

We present a method for rendering single-bounce indirect illumination in real time on currently available graphics hardware. The method is based on the instant radiosity algorithm, where virtual point lights (VPLs) are generated by casting rays from the primary light source. Hardware shadow maps are then employed for determining the indirect illumination from the VPLs. Our main contribution is an algorithm for reusing the VPLs and incrementally maintaining their good distribution. As a result, only a few shadow maps need to be rendered per frame as long as the motion of the primary light source is reasonably smooth. This yields real-time frame rates even when hundreds of VPLs are used.

Samuli Laine (NVIDIA and Helsinki University of Technology)
Hannu Saransaari (Helsinki University of Technology)
Janne Kontkanen (PDI/DreamWorks and Helsinki University of Technology)
Jaakko Lehtinen (Helsinki University of Technology and Remedy Entertainment)
Timo Aila (NVIDIA and Helsinki University of Technology)
Publication Date: 
Friday, June 1, 2007
Research Area: