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

13 files changed, 43 insertions, 38 deletions

diff --git a/source/blender/modifiers/intern/MOD_armature.c b/source/blender/modifiers/intern/MOD_armature.c
index 649d36e3d57..828b8b79664 100644
--- a/source/blender/modifiers/intern/MOD_armature.c
+++ b/source/blender/modifiers/intern/MOD_armature.c
@@ -37,6 +37,7 @@
 #include "BKE_action.h"
 #include "BKE_armature.h"
 #include "BKE_context.h"
+#include "BKE_deform.h"
 #include "BKE_editmesh.h"
 #include "BKE_lib_id.h"
 #include "BKE_lib_query.h"
@@ -122,7 +123,8 @@ static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphConte
       /* If neither vertex groups nor envelopes are used, the modifier has no bone dependencies. */
       if ((amd->deformflag & ARM_DEF_VGROUP) != 0) {
         /* Enumerate groups that match existing bones. */
-        LISTBASE_FOREACH (bDeformGroup *, dg, &ctx->object->defbase) {
+        const ListBase *defbase = BKE_object_defgroup_list(ctx->object);
+        LISTBASE_FOREACH (bDeformGroup *, dg, defbase) {
           if (BKE_pose_channel_find_name(amd->object->pose, dg->name) != NULL) {
             /* Can't check BONE_NO_DEFORM because it can be animated. */
             DEG_add_bone_relation(
diff --git a/source/blender/modifiers/intern/MOD_curve.c b/source/blender/modifiers/intern/MOD_curve.c
index 20dbb299767..aae6d257766 100644
--- a/source/blender/modifiers/intern/MOD_curve.c
+++ b/source/blender/modifiers/intern/MOD_curve.c
@@ -167,7 +167,7 @@ static void deformVertsEM(ModifierData *md,
   int defgrp_index = -1;
 
   if (ctx->object->type == OB_MESH && cmd->name[0] != '\0') {
-    defgrp_index = BKE_object_defgroup_name_index(ctx->object, cmd->name);
+    defgrp_index = BKE_id_defgroup_name_index(&mesh->id, cmd->name);
     if (defgrp_index != -1) {
       use_dverts = true;
     }
diff --git a/source/blender/modifiers/intern/MOD_mask.cc b/source/blender/modifiers/intern/MOD_mask.cc
index a77f6cfe8ba..9aa8e3dd7c8 100644
--- a/source/blender/modifiers/intern/MOD_mask.cc
+++ b/source/blender/modifiers/intern/MOD_mask.cc
@@ -119,7 +119,7 @@ static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphConte
 
 /* A vertex will be in the mask if a selected bone influences it more than a certain threshold. */
 static void compute_vertex_mask__armature_mode(MDeformVert *dvert,
-                                               Object *ob,
+                                               Mesh *mesh,
                                                Object *armature_ob,
                                                float threshold,
                                                MutableSpan<bool> r_vertex_mask)
@@ -127,7 +127,7 @@ static void compute_vertex_mask__armature_mode(MDeformVert *dvert,
   /* Element i is true if there is a selected bone that uses vertex group i. */
   Vector<bool> selected_bone_uses_group;
 
-  for (bDeformGroup *def : ListBaseWrapper<bDeformGroup>(ob->defbase)) {
+  LISTBASE_FOREACH (bDeformGroup *, def, &mesh->vertex_group_names) {
     bPoseChannel *pchan = BKE_pose_channel_find_name(armature_ob->pose, def->name);
     bool bone_for_group_exists = pchan && pchan->bone && (pchan->bone->flag & BONE_SELECTED);
     selected_bone_uses_group.append(bone_for_group_exists);
@@ -325,10 +325,9 @@ void copy_masked_polys_to_new_mesh(const Mesh &src_mesh,
  * 2. Find edges and polygons only using those vertices.
  * 3. Create a new mesh that only uses the found vertices, edges and polygons.
  */
-static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
+static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *UNUSED(ctx), Mesh *mesh)
 {
   MaskModifierData *mmd = reinterpret_cast<MaskModifierData *>(md);
-  Object *ob = ctx->object;
   const bool invert_mask = mmd->flag & MOD_MASK_INV;
 
   /* Return empty or input mesh when there are no vertex groups. */
@@ -339,7 +338,7 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
 
   /* Quick test to see if we can return early. */
   if (!(ELEM(mmd->mode, MOD_MASK_MODE_ARM, MOD_MASK_MODE_VGROUP)) || (mesh->totvert == 0) ||
-      BLI_listbase_is_empty(&ob->defbase)) {
+      BLI_listbase_is_empty(&mesh->vertex_group_names)) {
     return mesh;
   }
 
@@ -348,15 +347,15 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
     Object *armature_ob = mmd->ob_arm;
 
     /* Return input mesh if there is no armature with bones. */
-    if (ELEM(NULL, armature_ob, armature_ob->pose, ob->defbase.first)) {
+    if (ELEM(NULL, armature_ob, armature_ob->pose)) {
       return mesh;
     }
 
     vertex_mask = Array<bool>(mesh->totvert);
-    compute_vertex_mask__armature_mode(dvert, ob, armature_ob, mmd->threshold, vertex_mask);
+    compute_vertex_mask__armature_mode(dvert, mesh, armature_ob, mmd->threshold, vertex_mask);
   }
   else {
-    int defgrp_index = BKE_object_defgroup_name_index(ob, mmd->vgroup);
+    int defgrp_index = BKE_id_defgroup_name_index(&mesh->id, mmd->vgroup);
 
     /* Return input mesh if the vertex group does not exist. */
     if (defgrp_index == -1) {
diff --git a/source/blender/modifiers/intern/MOD_nodes.cc b/source/blender/modifiers/intern/MOD_nodes.cc
index 9af2472f2c6..87fce26c45e 100644
--- a/source/blender/modifiers/intern/MOD_nodes.cc
+++ b/source/blender/modifiers/intern/MOD_nodes.cc
@@ -1018,8 +1018,7 @@ static void modifyGeometry(ModifierData *md,
 static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
 {
   GeometrySet geometry_set = GeometrySet::create_with_mesh(mesh, GeometryOwnershipType::Editable);
-  geometry_set.get_component_for_write<MeshComponent>().copy_vertex_group_names_from_object(
-      *ctx->object);
+
   modifyGeometry(md, ctx, geometry_set);
 
   if (ctx->flag & MOD_APPLY_TO_BASE_MESH) {
diff --git a/source/blender/modifiers/intern/MOD_solidify_extrude.c b/source/blender/modifiers/intern/MOD_solidify_extrude.c
index a2fcbe35dcc..e97190b1878 100644
--- a/source/blender/modifiers/intern/MOD_solidify_extrude.c
+++ b/source/blender/modifiers/intern/MOD_solidify_extrude.c
@@ -242,9 +242,8 @@ Mesh *MOD_solidify_extrude_modifyMesh(ModifierData *md, const ModifierEvalContex
   MDeformVert *dvert;
   const bool defgrp_invert = (smd->flag & MOD_SOLIDIFY_VGROUP_INV) != 0;
   int defgrp_index;
-  const int shell_defgrp_index = BKE_object_defgroup_name_index(ctx->object,
-                                                                smd->shell_defgrp_name);
-  const int rim_defgrp_index = BKE_object_defgroup_name_index(ctx->object, smd->rim_defgrp_name);
+  const int shell_defgrp_index = BKE_id_defgroup_name_index(&mesh->id, smd->shell_defgrp_name);
+  const int rim_defgrp_index = BKE_id_defgroup_name_index(&mesh->id, smd->rim_defgrp_name);
 
   /* array size is doubled in case of using a shell */
   const uint stride = do_shell ? 2 : 1;
diff --git a/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c b/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
index 1a7daa10e0f..b872f04b60f 100644
--- a/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
+++ b/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
@@ -181,9 +181,8 @@ Mesh *MOD_solidify_nonmanifold_modifyMesh(ModifierData *md,
   MDeformVert *dvert;
   const bool defgrp_invert = (smd->flag & MOD_SOLIDIFY_VGROUP_INV) != 0;
   int defgrp_index;
-  const int shell_defgrp_index = BKE_object_defgroup_name_index(ctx->object,
-                                                                smd->shell_defgrp_name);
-  const int rim_defgrp_index = BKE_object_defgroup_name_index(ctx->object, smd->rim_defgrp_name);
+  const int shell_defgrp_index = BKE_id_defgroup_name_index(&mesh->id, smd->shell_defgrp_name);
+  const int rim_defgrp_index = BKE_id_defgroup_name_index(&mesh->id, smd->rim_defgrp_name);
 
   MOD_get_vgroup(ctx->object, mesh, smd->defgrp_name, &dvert, &defgrp_index);
 
diff --git a/source/blender/modifiers/intern/MOD_util.c b/source/blender/modifiers/intern/MOD_util.c
index 9aed4fbfc5f..5b97d0eb259 100644
--- a/source/blender/modifiers/intern/MOD_util.c
+++ b/source/blender/modifiers/intern/MOD_util.c
@@ -254,15 +254,22 @@ Mesh *MOD_deform_mesh_eval_get(Object *ob,
 void MOD_get_vgroup(
     Object *ob, struct Mesh *mesh, const char *name, MDeformVert **dvert, int *defgrp_index)
 {
-  *defgrp_index = BKE_object_defgroup_name_index(ob, name);
-  *dvert = NULL;
-
-  if (*defgrp_index != -1) {
-    if (ob->type == OB_LATTICE) {
+  if (mesh) {
+    *defgrp_index = BKE_id_defgroup_name_index(&mesh->id, name);
+    if (*defgrp_index != -1) {
+      *dvert = mesh->dvert;
+    }
+    else {
+      *dvert = NULL;
+    }
+  }
+  else {
+    *defgrp_index = BKE_object_defgroup_name_index(ob, name);
+    if (*defgrp_index != -1 && ob->type == OB_LATTICE) {
       *dvert = BKE_lattice_deform_verts_get(ob);
     }
-    else if (mesh) {
-      *dvert = mesh->dvert;
+    else {
+      *dvert = NULL;
     }
   }
 }
diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.c b/source/blender/modifiers/intern/MOD_weightvg_util.c
index c5e2ecb9660..696c4c855c7 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.c
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.c
@@ -230,7 +230,7 @@ void weightvg_do_mask(const ModifierEvalContext *ctx,
 
     MEM_freeN(tex_co);
   }
-  else if ((ref_didx = BKE_object_defgroup_name_index(ob, defgrp_name)) != -1) {
+  else if ((ref_didx = BKE_id_defgroup_name_index(&mesh->id, defgrp_name)) != -1) {
     MDeformVert *dvert = NULL;
 
     /* Check whether we want to set vgroup weights from a constant weight factor or a vertex
diff --git a/source/blender/modifiers/intern/MOD_weightvgedit.c b/source/blender/modifiers/intern/MOD_weightvgedit.c
index b5f72c88800..093fa118ee0 100644
--- a/source/blender/modifiers/intern/MOD_weightvgedit.c
+++ b/source/blender/modifiers/intern/MOD_weightvgedit.c
@@ -194,12 +194,12 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   /* Check if we can just return the original mesh.
    * Must have verts and therefore verts assigned to vgroups to do anything useful!
    */
-  if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+  if ((numVerts == 0) || BLI_listbase_is_empty(&mesh->vertex_group_names)) {
     return mesh;
   }
 
   /* Get vgroup idx from its name. */
-  const int defgrp_index = BKE_object_defgroup_name_index(ctx->object, wmd->defgrp_name);
+  const int defgrp_index = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name);
   if (defgrp_index == -1) {
     return mesh;
   }
diff --git a/source/blender/modifiers/intern/MOD_weightvgmix.c b/source/blender/modifiers/intern/MOD_weightvgmix.c
index a71a2f3b480..7aae089fa18 100644
--- a/source/blender/modifiers/intern/MOD_weightvgmix.c
+++ b/source/blender/modifiers/intern/MOD_weightvgmix.c
@@ -245,19 +245,19 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   /* Check if we can just return the original mesh.
    * Must have verts and therefore verts assigned to vgroups to do anything useful!
    */
-  if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+  if ((numVerts == 0) || BLI_listbase_is_empty(&mesh->vertex_group_names)) {
     return mesh;
   }
 
   /* Get vgroup idx from its name. */
-  const int defgrp_index = BKE_object_defgroup_name_index(ctx->object, wmd->defgrp_name_a);
+  const int defgrp_index = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name_a);
   if (defgrp_index == -1) {
     return mesh;
   }
   /* Get second vgroup idx from its name, if given. */
   int defgrp_index_other = -1;
   if (wmd->defgrp_name_b[0] != '\0') {
-    defgrp_index_other = BKE_object_defgroup_name_index(ctx->object, wmd->defgrp_name_b);
+    defgrp_index_other = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name_b);
     if (defgrp_index_other == -1) {
       return mesh;
     }
diff --git a/source/blender/modifiers/intern/MOD_weightvgproximity.c b/source/blender/modifiers/intern/MOD_weightvgproximity.c
index b0d2f52f78c..6e78774269a 100644
--- a/source/blender/modifiers/intern/MOD_weightvgproximity.c
+++ b/source/blender/modifiers/intern/MOD_weightvgproximity.c
@@ -468,7 +468,7 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   /* Check if we can just return the original mesh.
    * Must have verts and therefore verts assigned to vgroups to do anything useful!
    */
-  if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+  if ((numVerts == 0) || BLI_listbase_is_empty(&mesh->vertex_group_names)) {
     return mesh;
   }
 
@@ -479,11 +479,10 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   }
 
   /* Get vgroup idx from its name. */
-  defgrp_index = BKE_object_defgroup_name_index(ob, wmd->defgrp_name);
+  defgrp_index = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name);
   if (defgrp_index == -1) {
     return mesh;
   }
-
   const bool has_mdef = CustomData_has_layer(&mesh->vdata, CD_MDEFORMVERT);
   /* If no vertices were ever added to an object's vgroup, dvert might be NULL. */
   /* As this modifier never add vertices to vgroup, just return. */
diff --git a/source/blender/modifiers/intern/MOD_weld.c b/source/blender/modifiers/intern/MOD_weld.c
index 1590f342666..fe2d699aea8 100644
--- a/source/blender/modifiers/intern/MOD_weld.c
+++ b/source/blender/modifiers/intern/MOD_weld.c
@@ -1573,11 +1573,12 @@ struct WeldVertexCluster {
   uint merged_verts;
 };
 
-static Mesh *weldModifier_doWeld(WeldModifierData *wmd, const ModifierEvalContext *ctx, Mesh *mesh)
+static Mesh *weldModifier_doWeld(WeldModifierData *wmd,
+                                 const ModifierEvalContext *UNUSED(ctx),
+                                 Mesh *mesh)
 {
   Mesh *result = mesh;
 
-  Object *ob = ctx->object;
   BLI_bitmap *v_mask = NULL;
   int v_mask_act = 0;
 
@@ -1590,7 +1591,7 @@ static Mesh *weldModifier_doWeld(WeldModifierData *wmd, const ModifierEvalContex
   totvert = mesh->totvert;
 
   /* Vertex Group. */
-  const int defgrp_index = BKE_object_defgroup_name_index(ob, wmd->defgrp_name);
+  const int defgrp_index = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name);
   if (defgrp_index != -1) {
     MDeformVert *dvert, *dv;
     dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
diff --git a/source/blender/modifiers/intern/MOD_wireframe.c b/source/blender/modifiers/intern/MOD_wireframe.c
index 16bf1f7d763..e188a61e975 100644
--- a/source/blender/modifiers/intern/MOD_wireframe.c
+++ b/source/blender/modifiers/intern/MOD_wireframe.c
@@ -76,7 +76,7 @@ static Mesh *WireframeModifier_do(WireframeModifierData *wmd, Object *ob, Mesh *
   Mesh *result;
   BMesh *bm;
 
-  const int defgrp_index = BKE_object_defgroup_name_index(ob, wmd->defgrp_name);
+  const int defgrp_index = BKE_id_defgroup_name_index(&mesh->id, wmd->defgrp_name);
 
   bm = BKE_mesh_to_bmesh_ex(mesh,
                             &(struct BMeshCreateParams){0},