Refactoring mesh code, it has become clear that local cleanups and
simplifications are limited by the need to keep a C public API for
mesh functions. This change makes code more obvious and makes further
refactoring much easier.
- Add a new `BKE_mesh.hh` header for a C++ only mesh API
- Introduce a new `blender::bke::mesh` namespace, documented here:
https://wiki.blender.org/wiki/Source/Objects/Mesh#Namespaces
- Move some functions to the new namespace, cleaning up their arguments
- Move code to `Array` and `float3` where necessary to use the new API
- Define existing inline mesh data access functions to the new header
- Keep some C API functions where necessary because of RNA
- Move all C++ files to use the new header, which includes the old one
In the future it may make sense to split up `BKE_mesh.hh` more, but for
now keeping the same name as the existing header keeps things simple.
Pull Request: blender/blender#105416
Similar to the previous commit, this simplifies future refactoring
to change the way edges are stored, and further differentiates
single poly variables from array pointers.
Using spans instead of raw pointers helps to differentiate ararys from
pointers to single elements, gives bounds checking in debug builds, and
conveniently stores the number of elements in the same variable.
Also make variable naming consistent. For example, use `loops` instead
of `mloop`. The plural helps to clarify that the variable is an array.
I didn't change positions because there is a type mismatch between
C and C++ code that is ugly to manage. All remaining code can be
converted to C++, then that change will be simpler.
Pull Request #105138
