Optimize Volume Raycasting

[CaffeineViking]

Right now we have a constant step-size when raycasting (still somewhat reasonable since we jump one texel at a time), but a better solution would be to use the min-max volume (or something like that) to make "big strides" until something interesting happens (i.e. there is density there). This optimization is called Heirarchical Spatial Enumeration and can be seen over here. We already make use of Adaptive Termination but not to the same extent as they do. So yeah, right now we are constant-size-stepping through the volume at max resolution independent of the LoD. Also, doing so leads to noisy results at large distances, so we should be using a low resolution volume anyway (which means we need to modify the voxelization resolution, maybe by finding the best inverse projected size of a pixel -> voxel, and finding the resolution from there somehow).

Here is the short list of optimizations:

• Find the Voxelization Resolution
• Heirarchical Spatial Enumeration
• Expand on Adaptive Termination