A mapping from tiles to the meshes that each tile touches.
For each tile, the range of pointers in pointers that correspond to that tile.
This is a cumulative sum of the number of pointers in each bucket.
Bucket i will contain pointers in the range [i > 0 ? bucketRanges[i-1] : 0, bucketRanges[i]).
The length is the same as the number of tiles.
All meshes that should be voxelized.
Indices into the meshes array.