It seems to stay compatible with formatting done by clang-format 6.0 and 7.0,
so contributors can keep using those versions for now (they will not undo those
changes).
- From now materials assigned to the MeshInstance (not the Mesh) get exported
into the MeshLibrary when such materials exist. This enables workflows where
the MeshLibrary is exported from an imported scene (e.g. GLTF) where the
materials assigned to the Mesh (not the MeshInstance) get overwritten on
re-import, thus can't use editor set materials in the exported MeshLibrary
unless they are assigned to the MeshInstance whose materials get saved with
the inherited scene thus persist across re-imports.
- When appending to an existing MeshLibrary only generate previews for newly
added or modified meshes.
- During preview generation transform camera and lights instead of the mesh
and use the source MeshInstance's transform for the mesh to avoid weird
previews being generated for meshes with a position dependent material
(e.g. when using triplanar mapping).
- Adjust the camera angle and light directions used in mesh preview generation
for better results.
