   Any stable importance sampling for VPLs ?
  I'm experimenting with real-time GI algorithms right now. Ones that I'm trying are based on reflective shadow maps as a source for generating VPL. The main issue right now is to obtaine a coherent solution for VPL's position\flux. I would really appriciate some good advice on this, maybe I've just missed a paper that has a good solution.I have an idea but not sure how efficient that would be and how it can be mapped to GPU. During pre-process, possible positions for VPLs are scatered over the scene. Later, in real-time, each position is rendered from light point of view using points, so only one that can emmit light with current light orientation will be left in buffer. So basically it's a regular RSM but with a bit different way of rendering it. What I'm not getting is to how efficiently read VPLs from such texture, won't using CPU for this might be too slow? Or I just threat empty fragments as invalid VPLs and don't count them later during shading?   