I have been thinking.
Would it be possible to merge Voxels and spherical haromonics used in PRT techniques ?
Looking at this slide:
The most expensive operation is cone tracing.
But most of the time, cone tracing is wasted operation since most of the geometry is static, and only thing which is going to change is lighting information.
What if instead of tracing every so often, we would calculcate SH for every voxel and store it for further use (just as probes are used). In that case there would be much more information to store, than with probes.
Would it be possible to pre calculcate SH for voxel shapes, and then use those shapes at runtime to dynamically voxelize scene in radius, wrap voxels around geometry and then use precomputed SH for voxels, to calculate indirect lighting ?
It would be similar to MRT/DRT but instead of using primitive shapes, with precomputed SH, we would use voxels, to attach them around geometry.
Does it make sense ?
edit:
http://www.pmavridis.com/data/VolumeBasedDiffuseGlobalIllumination_final.pdf
Something alike what I have been thinking about.