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/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index 7ee6b4cdfc0..89983eb8f62 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -826,7 +826,7 @@ static void cloth_from_mesh(ClothModifierData *clmd, const Object *ob, Mesh *mes
   const MLoop *mloop = BKE_mesh_loops(mesh);
   const MLoopTri *looptri = BKE_mesh_runtime_looptri_ensure(mesh);
   const uint mvert_num = mesh->totvert;
-  const uint looptri_num = mesh->runtime.looptris.len;
+  const uint looptri_num = BKE_mesh_runtime_looptri_len(mesh);
 
   /* Allocate our vertices. */
   clmd->clothObject->mvert_num = mvert_num;