6d7dbdbb44
This is analagous to 6a71b2af66 which did the same
thing for mesh data. Two differences are that here the coordinates
are simply `float3`, and we account for the radius if it's available.
Here I observed a similar performance increase, from 50ms
average to 10ms average, with 16 million points, a 5x speedup.
The calculation is about 1.4 times faster when no radius is used, down
to 7.3ms average. Before, the calculation was only 1.2 times faster.