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, 2 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/subdiv_modifier.cc b/source/blender/blenkernel/intern/subdiv_modifier.cc
index a5529e9b8fa..84b772db045 100644
--- a/source/blender/blenkernel/intern/subdiv_modifier.cc
+++ b/source/blender/blenkernel/intern/subdiv_modifier.cc
@@ -11,6 +11,7 @@
 #include "DNA_scene_types.h"
 #include "DNA_userdef_types.h"
 
+#include "BKE_mesh.h"
 #include "BKE_modifier.h"
 #include "BKE_subdiv.h"
 
@@ -143,7 +144,7 @@ bool BKE_subsurf_modifier_can_do_gpu_subdiv(const Scene *scene,
 
 bool BKE_subsurf_modifier_has_gpu_subdiv(const Mesh *mesh)
 {
-  SubsurfRuntimeData *runtime_data = mesh->runtime.subsurf_runtime_data;
+  SubsurfRuntimeData *runtime_data = mesh->runtime->subsurf_runtime_data;
   return runtime_data && runtime_data->has_gpu_subdiv;
 }