(viz): do not compute normals in mesh adaptor
Description
Today, mesh normals may be computed at runtime in the mesh adaptor if the mesh does not provide them. This was exhibited in !704 (diffs) and this is clearly a design flaw. A mesh adaptor's responsibility is to display a mesh, not to modify it.
Proposal
- Remove the generation of normals in the SMesh adaptor. Beware that the shader pipeline expects normals, to either adapt it or trigger an error if normals are missing.
- If necessary, add optional or systematic normals generation in mesh readers.
- Add normals generation in mesh generators.
Functional specifications
Usually a refactor does not alter functional specifications, but if there is any change to the workflow, UX/UI design, screenshots, etc..., please describe it here
Technical specifications
Details of the implementation
Test plan
Describe how you will verify that the implementation fulfils the specifications