Function updateMeshPositions

Update a mesh's GPU vertex positions in place (e.g. CPU vertex animation). positions must hold tightly-packed XYZ floats. vertexOffset is the first destination vertex to overwrite (defaults to 0). vertexCount and sourceVertexOffset select a range from a retained full-size source array without allocating a view. The mesh must have been created via createMeshFromData / a mesh factory. Zero-allocation GPU upload only — CPU-side picking geometry is not refreshed.