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, 3 insertions, 17 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index ecbb3d1cfab..ba8cf8debe9 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -900,7 +900,7 @@ static Mesh *prepare_geometry_set_for_mesh_modifier(Mesh *mesh, GeometrySet &r_g
   {
     /* Add the mesh to the geometry set. */
     MeshComponent &mesh_component = r_geometry_set.get_component_for_write<MeshComponent>();
-    mesh_component.replace_mesh_but_keep_vertex_group_names(mesh, GeometryOwnershipType::Editable);
+    mesh_component.replace(mesh, GeometryOwnershipType::Editable);
   }
   {
     /* Combine mesh and all instances into a single mesh that can be passed to the modifier. */
@@ -948,8 +948,7 @@ static Mesh *modifier_modify_mesh_and_geometry_set(ModifierData *md,
     /* Replace only the mesh rather than the whole component, because the entire #MeshComponent
      * might have been replaced by data from a different object in the node tree, which means the
      * component contains vertex group name data for that object that should not be removed. */
-    mesh_component.replace_mesh_but_keep_vertex_group_names(input_mesh,
-                                                            GeometryOwnershipType::Editable);
+    mesh_component.replace(input_mesh, GeometryOwnershipType::Editable);
 
     /* Let the modifier change the geometry set. */
     mti->modifyGeometrySet(md, &mectx, &geometry_set);
@@ -993,12 +992,6 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
   /* This geometry set contains the non-mesh data that might be generated by modifiers. */
   GeometrySet geometry_set_final;
 
-  /* Add the initial mesh component, with a copy of the vertex group names from the object,
-   * since they need to be stored in the geometry set for evaluation. */
-  MeshComponent &initial_mesh_component =
-      geometry_set_final.get_component_for_write<MeshComponent>();
-  initial_mesh_component.copy_vertex_group_names_from_object(*ob);
-
   BLI_assert((mesh_input->id.tag & LIB_TAG_COPIED_ON_WRITE_EVAL_RESULT) == 0);
 
   /* Deformed vertex locations array. Deform only modifier need this type of
@@ -1602,12 +1595,6 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
   /* This geometry set contains the non-mesh data that might be generated by modifiers. */
   GeometrySet geometry_set_final;
 
-  /* Add the initial mesh component, with a copy of the vertex group names from the object,
-   * since they need to be stored in the geometry set for evaluation. */
-  MeshComponent &initial_mesh_component =
-      geometry_set_final.get_component_for_write<MeshComponent>();
-  initial_mesh_component.copy_vertex_group_names_from_object(*ob);
-
   /* Deformed vertex locations array. Deform only modifier need this type of
    * float array rather than MVert*. Tracked along with mesh_final as an
    * optimization to avoid copying coordinates back and forth if there are
@@ -1951,8 +1938,7 @@ static void mesh_build_data(struct Depsgraph *depsgraph,
 
   /* Add the final mesh as read-only non-owning component to the geometry set. */
   MeshComponent &mesh_component = geometry_set_eval->get_component_for_write<MeshComponent>();
-  mesh_component.replace_mesh_but_keep_vertex_group_names(mesh_eval,
-                                                          GeometryOwnershipType::ReadOnly);
+  mesh_component.replace(mesh_eval, GeometryOwnershipType::ReadOnly);
   ob->runtime.geometry_set_eval = geometry_set_eval;
 
   ob->runtime.mesh_deform_eval = mesh_deform_eval;