Until now, except for an attribute-less index-less mesh, the vertex
count was only implicitly taken from passed attributes, but it was
severely limiting:
- There was no way to set vertex count for an attribute-less
indexed mesh, which didn't make sense
- All code that made non-owning MeshData instances referencing another
MeshData had to explicitly handle the attribute-less corner case to
avoid vertex count getting lost
- Offset-only attributes couldn't be used to specify static layout of
meshes with dynamic vertex count, causing unnecessary extra
allocations especially in the Primitives library.
Vladimír Vondruš