Generate morph target normals and tangents if absent.

[schell]

Although the spec says we have to generate normals or tangents if not specified,
we are explicitly not doing that here.

renderling/crates/renderling/src/stage/gltf_support.rs

Lines 457 to 459 in 1ab3eeb

	// TODO: Generate morph target normals and tangents if absent.
	// Although the spec says we have to generate normals or tangents if not specified,
	// we are explicitly *not* doing that here.