Hierarchical Image-Space Radiosity for Interactive Global Illumination
Chris Wyman has posted a link to the preprint of the EGSR 2009 paper with Greg Nichols and myself. The paper builds on the multiresolution technique described in the I3D 2009 paper “Multiresolution Splatting for Indirect Illumination” by pairing it with two virtual point light clustering techniques. The first technique clusters VPLs that sample the same surface. This VPL similarity is determined using the same multiresolution discontinuity detection method from the last paper. The other clusters lights hierarchically and performs a traversal based on VPL contribution to the final image. Clustering VPLs allows two advantages: Performance scales with light-space scene complexity instead of the number of initial VPLs and flickering in indirect illumination due to temporal incoherence in reflective shadow map sampling is reduced.
The paper also offers a stencil buffer based implementation of the multiresolution illumination calculation technique detailed in the previous paper that offers dramatic performance improvement over the original geometry shader implementation.
Greg Nichols, Jeremy Shopf, and Chris Wyman. “Hierarchical Image-Space Radiosity for Interactive Global Illumination.” Accepted to the Eurographics Symposium on Rendering. (June 2009)
Related blog posts: Imperfect Shadow Maps – I3D 2009 Day 1 - Mixed Resolution Rendering