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, 16 insertions, 13 deletions

diff --git a/source/blender/editors/mesh/meshtools.c b/source/blender/editors/mesh/meshtools.c
index ca68c47cf8e..27fb21e1dfb 100644
--- a/source/blender/editors/mesh/meshtools.c
+++ b/source/blender/editors/mesh/meshtools.c
@@ -475,16 +475,17 @@ int ED_mesh_join_objects_exec(bContext *C, wmOperator *op)
       me = ob_iter->data;
 
       /* Join this object's vertex groups to the base one's */
-      for (dg = ob_iter->defbase.first; dg; dg = dg->next) {
+      for (dg = me->vertex_group_names.first; dg; dg = dg->next) {
         /* See if this group exists in the object (if it doesn't, add it to the end) */
         if (!BKE_object_defgroup_find_name(ob, dg->name)) {
           odg = MEM_mallocN(sizeof(bDeformGroup), "join deformGroup");
           memcpy(odg, dg, sizeof(bDeformGroup));
-          BLI_addtail(&ob->defbase, odg);
+          BLI_addtail(&mesh_active->vertex_group_names, odg);
         }
       }
-      if (ob->defbase.first && ob->actdef == 0) {
-        ob->actdef = 1;
+      if (!BLI_listbase_is_empty(&mesh_active->vertex_group_names) &&
+          me->vertex_group_active_index == 0) {
+        me->vertex_group_active_index = 1;
       }
 
       /* Join this object's face maps to the base one's. */
@@ -1473,19 +1474,21 @@ bool ED_mesh_pick_vert(
 
 MDeformVert *ED_mesh_active_dvert_get_em(Object *ob, BMVert **r_eve)
 {
-  if (ob->mode & OB_MODE_EDIT && ob->type == OB_MESH && ob->defbase.first) {
+  if (ob->mode & OB_MODE_EDIT && ob->type == OB_MESH) {
     Mesh *me = ob->data;
-    BMesh *bm = me->edit_mesh->bm;
-    const int cd_dvert_offset = CustomData_get_offset(&bm->vdata, CD_MDEFORMVERT);
+    if (!BLI_listbase_is_empty(&me->vertex_group_names)) {
+      BMesh *bm = me->edit_mesh->bm;
+      const int cd_dvert_offset = CustomData_get_offset(&bm->vdata, CD_MDEFORMVERT);
 
-    if (cd_dvert_offset != -1) {
-      BMVert *eve = BM_mesh_active_vert_get(bm);
+      if (cd_dvert_offset != -1) {
+        BMVert *eve = BM_mesh_active_vert_get(bm);
 
-      if (eve) {
-        if (r_eve) {
-          *r_eve = eve;
+        if (eve) {
+          if (r_eve) {
+            *r_eve = eve;
+          }
+          return BM_ELEM_CD_GET_VOID_P(eve, cd_dvert_offset);
         }
-        return BM_ELEM_CD_GET_VOID_P(eve, cd_dvert_offset);
       }
     }
   }