RaytracingWorker: Add support for BufferGeometry

[WestLangley]

I think that would be a valuable addition.

[mrdoob]

Agreed.

[WestLangley]

/ping @zz85 Any interest?

[zz85]

I'll try digging into it a little

[WestLangley]

@zz85 I think it would be OK in this case to remove support for legacy Geometry. At some point it will not be renderable anyway.

[zz85]

Just some updates from initial investigation - it seems like BufferGeometry has already some support in RaytracingWorker. MeshBasicMaterial works but not MeshPhongMaterial.

The reason is that checkBufferGeometryIntersection() in Mesh is not returning vertexNormals. could try modifying that method a little to see if that works.