gltfpack: Sort point mesh data by spatial locality
gltfpack: Sort point mesh data by spatial locality

Instead of using the original order the points came in, we now use
spatialSort to order points by spatial proximity.

This substantially increases the compression efficiency; for example,
kitchen.gltf before this change had almost incompressible data (24.5
bits color, 48.0 bits positions) due to the random order. After this
change, the color gets compressed to 16.5 bits and positions get
compressed to 20.1 bits.

zeux/meshoptimizer,zeux/meshoptimizer,zeux/meshoptimizer