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/multires.cc b/source/blender/blenkernel/intern/multires.cc
index 61cfe043927..5ff9602650e 100644
--- a/source/blender/blenkernel/intern/multires.cc
+++ b/source/blender/blenkernel/intern/multires.cc
@@ -397,7 +397,7 @@ void multires_mark_as_modified(Depsgraph *depsgraph, Object *object, MultiresMod
    * In a longer term maybe special dependency graph tag can help sanitizing this a bit. */
   Object *object_eval = DEG_get_evaluated_object(depsgraph, object);
   Mesh *mesh = static_cast<Mesh *>(object_eval->data);
-  SubdivCCG *subdiv_ccg = mesh->runtime.subdiv_ccg;
+  SubdivCCG *subdiv_ccg = mesh->runtime->subdiv_ccg;
   if (subdiv_ccg == nullptr) {
     return;
   }