I've had another attempt at sparse volumes for my voxel-like renderer. A bit late though, I've been thoroughly beaten to it. Not that surprising, considering how many years I've been chipping away at it (and, lately, just plain neglecting it).

This sparse volume is much simpler than previous attempts, and as such, works quite a bit better. I've got a 2048^3 volume working, with floating point radii, and it's taking around a gig of ram. And let me say this: You have no idea how big a 2048^3 volume is. Here's a picture:

You see each of the little squares on the left? They're 8 grid points across. Each 8^3 bunch of radii is coloured like a colour cube. There are artifacts, but I don't care at the moment. I'm tired.