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, 154 insertions, 28 deletions

diff --git a/source/blender/blenkernel/intern/deform.c b/source/blender/blenkernel/intern/deform.c
index 19840a70bf0..f7ef84728b6 100644
--- a/source/blender/blenkernel/intern/deform.c
+++ b/source/blender/blenkernel/intern/deform.c
@@ -29,6 +29,8 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "DNA_gpencil_types.h"
+#include "DNA_lattice_types.h"
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "DNA_object_types.h"
@@ -64,7 +66,9 @@ bDeformGroup *BKE_object_defgroup_new(Object *ob, const char *name)
 
   BLI_strncpy(defgroup->name, name, sizeof(defgroup->name));
 
-  BLI_addtail(&ob->defbase, defgroup);
+  ListBase *defbase = BKE_object_defgroup_list_mutable(ob);
+
+  BLI_addtail(defbase, defgroup);
   BKE_object_defgroup_unique_name(defgroup, ob);
 
   BKE_object_batch_cache_dirty_tag(ob);
@@ -484,18 +488,120 @@ void BKE_defvert_flip_merged(MDeformVert *dvert, const int *flip_map, const int
   }
 }
 
+bool BKE_object_supports_vertex_groups(const Object *ob)
+{
+  const ID *id = (const ID *)ob->data;
+  if (id == NULL) {
+    return false;
+  }
+
+  return ELEM(GS(id->name), ID_ME, ID_LT, ID_GD);
+}
+
+const ListBase *BKE_id_defgroup_list_get(const ID *id)
+{
+  switch (GS(id->name)) {
+    case ID_ME: {
+      const Mesh *me = (const Mesh *)id;
+      return &me->vertex_group_names;
+    }
+    case ID_LT: {
+      const Lattice *lt = (const Lattice *)id;
+      return &lt->vertex_group_names;
+    }
+    case ID_GD: {
+      const bGPdata *gpd = (const bGPdata *)id;
+      return &gpd->vertex_group_names;
+    }
+    default: {
+      BLI_assert_unreachable();
+    }
+  }
+  return NULL;
+}
+
+static const int *object_defgroup_active_index_get_p(const Object *ob)
+{
+  BLI_assert(BKE_object_supports_vertex_groups(ob));
+  switch (ob->type) {
+    case OB_MESH: {
+      const Mesh *mesh = (const Mesh *)ob->data;
+      return &mesh->vertex_group_active_index;
+    }
+    case OB_LATTICE: {
+      const Lattice *lattice = (const Lattice *)ob->data;
+      return &lattice->vertex_group_active_index;
+    }
+    case OB_GPENCIL: {
+      const bGPdata *gpd = (const bGPdata *)ob->data;
+      return &gpd->vertex_group_active_index;
+    }
+  }
+  return NULL;
+}
+
+ListBase *BKE_id_defgroup_list_get_mutable(ID *id)
+{
+  /* Cast away const just for the accessor. */
+  return (ListBase *)BKE_id_defgroup_list_get(id);
+}
+
 bDeformGroup *BKE_object_defgroup_find_name(const Object *ob, const char *name)
 {
-  return (name && name[0] != '\0') ?
-             BLI_findstring(&ob->defbase, name, offsetof(bDeformGroup, name)) :
-             NULL;
+  if (name == NULL || name[0] == '\0') {
+    return NULL;
+  }
+  const ListBase *defbase = BKE_object_defgroup_list(ob);
+  return BLI_findstring(defbase, name, offsetof(bDeformGroup, name));
+}
+
+int BKE_id_defgroup_name_index(const ID *id, const char *name)
+{
+  if (name == NULL || name[0] == '\0') {
+    return -1;
+  }
+  const ListBase *defbase = BKE_id_defgroup_list_get(id);
+  return BLI_findstringindex(defbase, name, offsetof(bDeformGroup, name));
+}
+
+const ListBase *BKE_object_defgroup_list(const Object *ob)
+{
+  BLI_assert(BKE_object_supports_vertex_groups(ob));
+  return BKE_id_defgroup_list_get((const ID *)ob->data);
 }
 
 int BKE_object_defgroup_name_index(const Object *ob, const char *name)
 {
-  return (name && name[0] != '\0') ?
-             BLI_findstringindex(&ob->defbase, name, offsetof(bDeformGroup, name)) :
-             -1;
+  return BKE_id_defgroup_name_index((ID *)ob->data, name);
+}
+
+ListBase *BKE_object_defgroup_list_mutable(Object *ob)
+{
+  BLI_assert(BKE_object_supports_vertex_groups(ob));
+  return BKE_id_defgroup_list_get_mutable((ID *)ob->data);
+}
+
+int BKE_object_defgroup_count(const Object *ob)
+{
+  return BLI_listbase_count(BKE_object_defgroup_list(ob));
+}
+
+/**
+ * \note For historical reasons, the index starts at 1 rather than 0.
+ */
+int BKE_object_defgroup_active_index_get(const Object *ob)
+{
+  return *object_defgroup_active_index_get_p(ob);
+}
+
+/**
+ * \note For historical reasons, the index starts at 1 rather than 0.
+ */
+void BKE_object_defgroup_active_index_set(Object *ob, const int new_index)
+{
+  /* Cast away const just for the accessor. */
+  int *index = (int *)object_defgroup_active_index_get_p(ob);
+  *index = new_index;
 }
 
 /**
@@ -503,7 +609,8 @@ int BKE_object_defgroup_name_index(const Object *ob, const char *name)
  */
 int *BKE_object_defgroup_flip_map(const Object *ob, int *flip_map_len, const bool use_default)
 {
-  int defbase_tot = *flip_map_len = BLI_listbase_count(&ob->defbase);
+  const ListBase *defbase = BKE_object_defgroup_list(ob);
+  int defbase_tot = *flip_map_len = BLI_listbase_count(defbase);
 
   if (defbase_tot == 0) {
     return NULL;
@@ -517,7 +624,7 @@ int *BKE_object_defgroup_flip_map(const Object *ob, int *flip_map_len, const boo
     map[i] = -1;
   }
 
-  for (dg = ob->defbase.first, i = 0; dg; dg = dg->next, i++) {
+  for (dg = defbase->first, i = 0; dg; dg = dg->next, i++) {
     if (map[i] == -1) { /* may be calculated previously */
 
       /* in case no valid value is found, use this */
@@ -547,7 +654,8 @@ int *BKE_object_defgroup_flip_map_single(const Object *ob,
                                          const bool use_default,
                                          int defgroup)
 {
-  int defbase_tot = *flip_map_len = BLI_listbase_count(&ob->defbase);
+  const ListBase *defbase = BKE_object_defgroup_list(ob);
+  int defbase_tot = *flip_map_len = BLI_listbase_count(defbase);
 
   if (defbase_tot == 0) {
     return NULL;
@@ -561,7 +669,7 @@ int *BKE_object_defgroup_flip_map_single(const Object *ob,
     map[i] = use_default ? i : -1;
   }
 
-  dg = BLI_findlink(&ob->defbase, defgroup);
+  dg = BLI_findlink(defbase, defgroup);
 
   BLI_string_flip_side_name(name_flip, dg->name, false, sizeof(name_flip));
   if (!STREQ(name_flip, dg->name)) {
@@ -578,7 +686,8 @@ int *BKE_object_defgroup_flip_map_single(const Object *ob,
 
 int BKE_object_defgroup_flip_index(const Object *ob, int index, const bool use_default)
 {
-  bDeformGroup *dg = BLI_findlink(&ob->defbase, index);
+  const ListBase *defbase = BKE_object_defgroup_list(ob);
+  bDeformGroup *dg = BLI_findlink(defbase, index);
   int flip_index = -1;
 
   if (dg) {
@@ -595,9 +704,10 @@ int BKE_object_defgroup_flip_index(const Object *ob, int index, const bool use_d
 
 static bool defgroup_find_name_dupe(const char *name, bDeformGroup *dg, Object *ob)
 {
+  const ListBase *defbase = BKE_object_defgroup_list(ob);
   bDeformGroup *curdef;
 
-  for (curdef = ob->defbase.first; curdef; curdef = curdef->next) {
+  for (curdef = defbase->first; curdef; curdef = curdef->next) {
     if (dg != curdef) {
       if (STREQ(curdef->name, name)) {
         return true;
@@ -1189,7 +1299,10 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
 {
   int idx_src;
   int idx_dst;
-  int tot_dst = BLI_listbase_count(&ob_dst->defbase);
+  const ListBase *src_list = BKE_object_defgroup_list(ob_src);
+  ListBase *dst_defbase = BKE_object_defgroup_list_mutable(ob_dst);
+
+  int tot_dst = BLI_listbase_count(dst_defbase);
 
   const size_t elem_size = sizeof(*((MDeformVert *)NULL));
 
@@ -1218,7 +1331,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
       }
       else if (use_delete && idx_dst > idx_src) {
         while (idx_dst-- > idx_src) {
-          BKE_object_defgroup_remove(ob_dst, ob_dst->defbase.last);
+          BKE_object_defgroup_remove(ob_dst, dst_defbase->last);
         }
       }
       if (r_map) {
@@ -1255,7 +1368,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
 
       if (use_delete) {
         /* Remove all unused dst vgroups first, simpler in this case. */
-        for (dg_dst = ob_dst->defbase.first; dg_dst;) {
+        for (dg_dst = dst_defbase->first; dg_dst;) {
           bDeformGroup *dg_dst_next = dg_dst->next;
 
           if (BKE_object_defgroup_name_index(ob_src, dg_dst->name) == -1) {
@@ -1265,7 +1378,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
         }
       }
 
-      for (idx_src = 0, dg_src = ob_src->defbase.first; idx_src < num_layers_src;
+      for (idx_src = 0, dg_src = src_list->first; idx_src < num_layers_src;
            idx_src++, dg_src = dg_src->next) {
         if (!use_layers_src[idx_src]) {
           continue;
@@ -1274,7 +1387,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
         if ((idx_dst = BKE_object_defgroup_name_index(ob_dst, dg_src->name)) == -1) {
           if (use_create) {
             BKE_object_defgroup_add_name(ob_dst, dg_src->name);
-            idx_dst = ob_dst->actdef - 1;
+            idx_dst = BKE_object_defgroup_active_index_get(ob_dst) - 1;
           }
           else {
             /* If we are not allowed to create missing dst vgroups, just skip matching src one. */
@@ -1340,8 +1453,12 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
    * This implies we may have to handle data layout itself while having NULL data itself,
    * and even have to support NULL data_src in transfer data code
    * (we always create a data_dst, though).
+   *
+   * Note: Above comment is outdated, but this function was written when that was true.
    */
-  if (BLI_listbase_is_empty(&ob_src->defbase)) {
+
+  const ListBase *src_defbase = BKE_object_defgroup_list(ob_src);
+  if (BLI_listbase_is_empty(src_defbase)) {
     if (use_delete) {
       BKE_object_defgroup_remove_all(ob_dst);
     }
@@ -1361,35 +1478,37 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
 
     if (fromlayers >= 0) {
       idx_src = fromlayers;
-      if (idx_src >= BLI_listbase_count(&ob_src->defbase)) {
+      if (idx_src >= BLI_listbase_count(src_defbase)) {
         /* This can happen when vgroups are removed from source object...
          * Remapping would be really tricky here, we'd need to go over all objects in
          * Main every time we delete a vgroup... for now, simpler and safer to abort. */
         return false;
       }
     }
-    else if ((idx_src = ob_src->actdef - 1) == -1) {
+    else if ((idx_src = BKE_object_defgroup_active_index_get(ob_src) - 1) == -1) {
       return false;
     }
 
     if (tolayers >= 0) {
       /* NOTE: in this case we assume layer exists! */
       idx_dst = tolayers;
-      BLI_assert(idx_dst < BLI_listbase_count(&ob_dst->defbase));
+      const ListBase *dst_defbase = BKE_object_defgroup_list(ob_dst);
+      BLI_assert(idx_dst < BLI_listbase_count(dst_defbase));
+      UNUSED_VARS_NDEBUG(dst_defbase);
     }
     else if (tolayers == DT_LAYERS_ACTIVE_DST) {
-      if ((idx_dst = ob_dst->actdef - 1) == -1) {
+      if ((idx_dst = BKE_object_defgroup_active_index_get(ob_dst) - 1) == -1) {
         bDeformGroup *dg_src;
         if (!use_create) {
           return true;
         }
-        dg_src = BLI_findlink(&ob_src->defbase, idx_src);
+        dg_src = BLI_findlink(src_defbase, idx_src);
         BKE_object_defgroup_add_name(ob_dst, dg_src->name);
-        idx_dst = ob_dst->actdef - 1;
+        idx_dst = BKE_object_defgroup_active_index_get(ob_dst) - 1;
       }
     }
     else if (tolayers == DT_LAYERS_INDEX_DST) {
-      int num = BLI_listbase_count(&ob_src->defbase);
+      int num = BLI_listbase_count(src_defbase);
       idx_dst = idx_src;
       if (num <= idx_dst) {
         if (!use_create) {
@@ -1402,13 +1521,13 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
       }
     }
     else if (tolayers == DT_LAYERS_NAME_DST) {
-      bDeformGroup *dg_src = BLI_findlink(&ob_src->defbase, idx_src);
+      bDeformGroup *dg_src = BLI_findlink(src_defbase, idx_src);
       if ((idx_dst = BKE_object_defgroup_name_index(ob_dst, dg_src->name)) == -1) {
         if (!use_create) {
           return true;
         }
         BKE_object_defgroup_add_name(ob_dst, dg_src->name);
-        idx_dst = ob_dst->actdef - 1;
+        idx_dst = BKE_object_defgroup_active_index_get(ob_dst) - 1;
       }
     }
     else {
@@ -1531,6 +1650,13 @@ void BKE_defvert_weight_to_rgb(float r_rgb[3], const float weight)
 /** \name .blend file I/O
  * \{ */
 
+void BKE_defbase_blend_write(BlendWriter *writer, const ListBase *defbase)
+{
+  LISTBASE_FOREACH (bDeformGroup *, defgroup, defbase) {
+    BLO_write_struct(writer, bDeformGroup, defgroup);
+  }
+}
+
 void BKE_defvert_blend_write(BlendWriter *writer, int count, MDeformVert *dvlist)
 {
   if (dvlist == NULL) {