.splat file compression

[dylanebert]

The size of .splat files could be reduced by 4x, without any quality loss, by working directly with the SplatTexture format, which they are rendered from anyway.

A magic header could be added for backwards compatibility.

[softyoda]

Hi, I wish to know will this be an integration of the optimization of @mkkellogg
compression to have the same format? Or will have to re-process plys to .splat format?

[dylanebert]

I think it would be nice to have cross compatibility. I'll check out his implementation and see if we can come to a universal .splat format

edit: opened an issue in the mkkellogg repo about establishing a universal .splat format

[julien-blanchon]

Could be nice to anticipate some possible quantize format such as what as be done by playcanvas here playcanvas/engine#5831