Mesh: Move runtime data out of DNA

This commit replaces the `Mesh_Runtime` struct embedded in `Mesh`
with `blender::bke::MeshRuntime`. This has quite a few benefits:
- It's possible to use C++ types like `std::mutex`, `Array`,
  `BitVector`, etc. more easily
- Meshes saved in files are slightly smaller
- Copying and writing meshes is a bit more obvious without
  clearing of runtime data, etc.

The first is by far the most important. It will allows us to avoid a
bunch of manual memory management boilerplate that is error-prone and
annoying. It should also simplify future CoW improvements for runtime
data.

This patch doesn't change anything besides changing `mesh.runtime.data`
to `mesh.runtime->data`. The cleanups above will happen separately.

Differential Revision: https://developer.blender.org/D16180

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/bmesh/intern/bmesh_mesh_convert.cc b/source/blender/bmesh/intern/bmesh_mesh_convert.cc
index dfbdd64ee7c..82d707c7e54 100644
--- a/source/blender/bmesh/intern/bmesh_mesh_convert.cc
+++ b/source/blender/bmesh/intern/bmesh_mesh_convert.cc
@@ -1238,7 +1238,7 @@ void BM_mesh_bm_to_me_for_eval(BMesh *bm, Mesh *me, const CustomData_MeshMasks *
    * different than the BMesh's. */
   BKE_mesh_clear_derived_normals(me);
 
-  me->runtime.deformed_only = true;
+  me->runtime->deformed_only = true;
 
   bke::MutableAttributeAccessor mesh_attributes = me->attributes_for_write();