This checkin adds a --flatten-uniform-arrays option which can break
uniform arrays of samplers, textures, or UBOs up into individual
scalars named (e.g) myarray[0], myarray[1], etc. These appear as
individual linkage objects.
Code notes:
- shouldFlatten internally calls shouldFlattenIO, and shouldFlattenUniform,
but is the only flattening query directly called.
- flattenVariable will handle structs or arrays (but not yet arrayed structs;
this is tested an an error is generated).
- There's some error checking around unhandled situations. E.g, flattening
uniform arrays with initializer lists is not implemented.
- This piggybacks on as much of the existing mechanism for struct flattening
as it can. E.g, it uses the same flattenMap, and the same
flattenAccess() method.
- handleAssign() has been generalized to cope with either structs or arrays.
- Extended test infrastructure to test flattening ability.
