World-space AABB covered by the root voxel: [minX, minY, minZ, maxX, maxY, maxZ].
Packed integer coordinates of voxel minimum corners, relative to
VoxelGrid.origin and expressed at each voxel's resolution:
[x0, y0, z0, x1, y1, z1, ...].
Resolution index for each voxel. granularities[levels[i]] gives its world-space size.
Integer coordinates of the root voxel owning this spatial chunk: [x, y, z].
One VoxelState value for each voxel.
Voxel data for one spatial chunk (the voxels under one root voxel), stored as packed typed-array buffers so it can be transferred between workers without copying.