Blender USD import already supports the displayColor primvar, when it is
specified on Mesh prims. These colors are visible in the viewport when
the viewport shading color type is set to Attribute.
This PR extends this displayColor primvar support to also work with the
various shape prims, such as Box, Sphere, etc.
The original displayColor support was implemented in USDMeshReader.
Because USDShapeReader is a sibling to to USDMeshReader, and
USDShapeReader first converts shapes to a Mesh, we have factored out the
mutually beneficial code from usd_reader_mesh.cc into a new usd_mesh_utils.cc.
For now only the displayColor primvar is supported on shapes, but this
could be easily extended in a future PR.
Authored by Apple: Matt McLin
Co-authored-by: Michael Kowalski <makowalski@nvidia.com>
Pull Request: https://projects.blender.org/blender/blender/pulls/120236
f91b23ef2d