Sparse voxel octrees aren’t good for GPU’s simply because they don’t map linearly to memory, causing all the nice parallelisation that GPUs are good at to go out the window. Which is why many people looking at voxel cone tracing have switched to uniform 3d textures, which is a very nice speed up but can take up a lot more ram if you aren’t very, very clever.
Bleh, just another “look at what we can do in Sponza!” type demo. Highly dependent on view direction and scene complexity isn’t something that’s a good solution.
Screenspace tracing stuff was invented because you already had to do all the heavy lifting of rendering everything there to begin with, and re-using it relatively cheaply made sense. This is just a wrong headed approach of taking the “cheap” portion of 2.5d screenspace tracing and extending by adding yet more of the brute force portion of rendering everything to screenspace to begin with.
Besides, notice A. That it’s recorded at just 30fps on a Titan, which is really a nice bottom performance requirement to have. B. during the global illumination demo they never do something an actual player would do, which is just turn around and face away from the light. Because then all the lighting would disappear! Really I’d not bother with this.