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, 3 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index 6d42d344b86..d6dd3cf0dbb 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -60,6 +60,7 @@
 #include "BKE_material.h"
 #include "BKE_mesh.h"
 #include "BKE_mesh_legacy_convert.h"
+#include "BKE_mesh_runtime.h"
 #include "BKE_modifier.h"
 #include "BKE_object.h"
 #include "BKE_particle.h"
@@ -1933,7 +1934,7 @@ int psys_particle_dm_face_lookup(Mesh *mesh_final,
     index_mf_to_mpoly_deformed = CustomData_get_layer(&mesh_original->fdata, CD_ORIGINDEX);
   }
   else {
-    BLI_assert(mesh_final->runtime.deformed_only);
+    BLI_assert(BKE_mesh_is_deformed_only(mesh_final));
     index_mf_to_mpoly_deformed = index_mf_to_mpoly;
   }
   BLI_assert(index_mf_to_mpoly_deformed);
@@ -2023,7 +2024,7 @@ static int psys_map_index_on_dm(Mesh *mesh,
     return 0;
   }
 
-  if (mesh->runtime.deformed_only || index_dmcache == DMCACHE_ISCHILD) {
+  if (BKE_mesh_is_deformed_only(mesh) || index_dmcache == DMCACHE_ISCHILD) {
     /* for meshes that are either only deformed or for child particles, the
      * index and fw do not require any mapping, so we can directly use it */
     if (from == PART_FROM_VERT) {