chunked re-sort updating #45
Description
the splat re-sort process currently causes noticeable lag on Meta Quest 3. To mitigate this, split the model into octree chunks, with a set number of splats in each chunk. Load these as separate splats. At run time, have a budget of chunks that will get re-sorted in a given step, and prioritize based on proximity to the camera and age since last re-sort.