Refactor: Move vertex group names to object data

This commit moves the storage of `bDeformGroup` and the active index
to `Mesh`, `Lattice`, and `bGPdata` instead of `Object`. Utility
functions are added to allow easy access to the vertex groups given
an object or an ID.

As explained in T88951, the list of vertex group names is currently
stored separately per object, even though vertex group data is stored
on the geometry. This tends to complicate code and cause bugs,
especially as geometry is created procedurally and tied less closely
to an object.

The "Copy Vertex Groups to Linked" operator is removed, since they
are stored on the geometry anyway.

This patch leaves the object-level python API for vertex groups in
place. Creating a geometry-level RNA API can be a separate step;
the changes in this commit are invasive enough as it is.

Note that opening a file saved in 3.0 in an earlier version means
the vertex groups will not be available.

Differential Revision: https://developer.blender.org/D11689

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index a92401d3ba0..c4186ad3180 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -39,6 +39,7 @@
 #include "BLI_ghash.h"
 #include "BLI_hash.h"
 #include "BLI_linklist.h"
+#include "BLI_listbase.h"
 #include "BLI_math.h"
 #include "BLI_memarena.h"
 #include "BLI_string.h"
@@ -125,6 +126,8 @@ static void mesh_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
 
   mesh_dst->mat = MEM_dupallocN(mesh_src->mat);
 
+  BKE_defgroup_copy_list(&mesh_dst->vertex_group_names, &mesh_src->vertex_group_names);
+
   const eCDAllocType alloc_type = (flag & LIB_ID_COPY_CD_REFERENCE) ? CD_REFERENCE : CD_DUPLICATE;
   CustomData_copy(&mesh_src->vdata, &mesh_dst->vdata, mask.vmask, alloc_type, mesh_dst->totvert);
   CustomData_copy(&mesh_src->edata, &mesh_dst->edata, mask.emask, alloc_type, mesh_dst->totedge);
@@ -155,6 +158,8 @@ static void mesh_free_data(ID *id)
 {
   Mesh *mesh = (Mesh *)id;
 
+  BLI_freelistN(&mesh->vertex_group_names);
+
   BKE_mesh_runtime_clear_cache(mesh);
   mesh_clear_geometry(mesh);
   MEM_SAFE_FREE(mesh->mat);
@@ -229,6 +234,8 @@ static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address
       BKE_animdata_blend_write(writer, mesh->adt);
     }
 
+    BKE_defbase_blend_write(writer, &mesh->vertex_group_names);
+
     BLO_write_pointer_array(writer, mesh->totcol, mesh->mat);
     BLO_write_raw(writer, sizeof(MSelect) * mesh->totselect, mesh->mselect);
 
@@ -288,6 +295,7 @@ static void mesh_blend_read_data(BlendDataReader *reader, ID *id)
   /* Normally BKE_defvert_blend_read should be called in CustomData_blend_read,
    * but for backwards compatibility in do_versions to work we do it here. */
   BKE_defvert_blend_read(reader, mesh->totvert, mesh->dvert);
+  BLO_read_list(reader, &mesh->vertex_group_names);
 
   CustomData_blend_read(reader, &mesh->vdata, mesh->totvert);
   CustomData_blend_read(reader, &mesh->edata, mesh->totedge);
@@ -923,6 +931,12 @@ void BKE_mesh_copy_parameters(Mesh *me_dst, const Mesh *me_src)
   me_dst->texflag = me_src->texflag;
   copy_v3_v3(me_dst->loc, me_src->loc);
   copy_v3_v3(me_dst->size, me_src->size);
+
+  /* Some callers call this on existing meshes, so free the existing vertex groups first. */
+  BLI_freelistN(&me_dst->vertex_group_names);
+  BKE_defgroup_copy_list(&me_dst->vertex_group_names, &me_src->vertex_group_names);
+
+  me_dst->vertex_group_active_index = me_src->vertex_group_active_index;
 }
 
 /**