Merge branch 'blender-v2.92-release'

3 files changed, 40 insertions, 14 deletions

diff --git a/source/blender/blenkernel/BKE_geometry_set.hh b/source/blender/blenkernel/BKE_geometry_set.hh
index 51f7507bd6c..2bed1a36ed7 100644
--- a/source/blender/blenkernel/BKE_geometry_set.hh
+++ b/source/blender/blenkernel/BKE_geometry_set.hh
@@ -354,6 +354,8 @@ class MeshComponent : public GeometryComponent {
   void clear();
   bool has_mesh() const;
   void replace(Mesh *mesh, GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
+  void replace_mesh_but_keep_vertex_group_names(
+      Mesh *mesh, GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
   Mesh *release();
 
   void copy_vertex_group_names_from_object(const struct Object &object);
diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index d79413cfaa0..ecc41e3f0df 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -883,16 +883,15 @@ void BKE_mesh_wrapper_deferred_finalize(Mesh *me_eval,
 }
 
 /**
- * Modifies the given mesh and geometry set. The geometry set is expect to have NO mesh component.
- * After this function ends, the geometry set will still have NO mesh component. Instead, an input
- * mesh is passed separately and is returned separately.
+ * Modifies the given mesh and geometry set. The mesh is not passed as part of the mesh component
+ * in the \a geometry_set input, it is only passed in \a input_mesh and returned in the return
+ * value.
  *
- * The purpose of the geometry set is to store all non-mesh geometry components that are generated
- * by modifiers.
+ * The purpose of the geometry set is to store all geometry components that are generated
+ * by modifiers to allow outputting non-mesh data from modifiers.
  */
 static Mesh *modifier_modify_mesh_and_geometry_set(ModifierData *md,
                                                    const ModifierEvalContext &mectx,
-                                                   Object *ob,
                                                    Mesh *input_mesh,
                                                    GeometrySet &geometry_set)
 {
@@ -907,10 +906,12 @@ static Mesh *modifier_modify_mesh_and_geometry_set(ModifierData *md,
     BKE_mesh_wrapper_ensure_mdata(input_mesh);
 
     /* Adds a new mesh component to the geometry set based on the #input_mesh. */
-    BLI_assert(!geometry_set.has<MeshComponent>());
     MeshComponent &mesh_component = geometry_set.get_component_for_write<MeshComponent>();
-    mesh_component.replace(input_mesh, GeometryOwnershipType::Editable);
-    mesh_component.copy_vertex_group_names_from_object(*ob);
+    /* 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);
 
     /* Let the modifier change the geometry set. */
     mti->modifyGeometrySet(md, &mectx, &geometry_set);
@@ -919,7 +920,6 @@ static Mesh *modifier_modify_mesh_and_geometry_set(ModifierData *md,
     if (geometry_set.has<MeshComponent>()) {
       MeshComponent &mesh_component = geometry_set.get_component_for_write<MeshComponent>();
       mesh_output = mesh_component.release();
-      geometry_set.remove<MeshComponent>();
     }
 
     /* Return an empty mesh instead of null.  */
@@ -954,6 +954,13 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
   Mesh *mesh_deform = nullptr;
   /* 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
@@ -1252,7 +1259,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
       }
 
       Mesh *mesh_next = modifier_modify_mesh_and_geometry_set(
-          md, mectx, ob, mesh_final, geometry_set_final);
+          md, mectx, mesh_final, geometry_set_final);
       ASSERT_IS_VALID_MESH(mesh_next);
 
       if (mesh_next) {
@@ -1717,7 +1724,7 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
       }
 
       Mesh *mesh_next = modifier_modify_mesh_and_geometry_set(
-          md, mectx, ob, mesh_final, geometry_set_final);
+          md, mectx, mesh_final, geometry_set_final);
       ASSERT_IS_VALID_MESH(mesh_next);
 
       if (mesh_next) {
@@ -1893,9 +1900,9 @@ static void mesh_build_data(struct Depsgraph *depsgraph,
   BKE_object_eval_assign_data(ob, &mesh_eval->id, is_mesh_eval_owned);
 
   /* Add the final mesh as read-only non-owning component to the geometry set. */
-  BLI_assert(!geometry_set_eval->has<MeshComponent>());
   MeshComponent &mesh_component = geometry_set_eval->get_component_for_write<MeshComponent>();
-  mesh_component.replace(mesh_eval, GeometryOwnershipType::ReadOnly);
+  mesh_component.replace_mesh_but_keep_vertex_group_names(mesh_eval,
+                                                          GeometryOwnershipType::ReadOnly);
   ob->runtime.geometry_set_eval = geometry_set_eval;
 
   ob->runtime.mesh_deform_eval = mesh_deform_eval;
diff --git a/source/blender/blenkernel/intern/geometry_set.cc b/source/blender/blenkernel/intern/geometry_set.cc
index 833e1dd3719..dae0b757df0 100644
--- a/source/blender/blenkernel/intern/geometry_set.cc
+++ b/source/blender/blenkernel/intern/geometry_set.cc
@@ -339,6 +339,23 @@ void MeshComponent::replace(Mesh *mesh, GeometryOwnershipType ownership)
   ownership_ = ownership;
 }
 
+/* This function exists for the same reason as #vertex_group_names_. Non-nodes modifiers need to
+ * be able to replace the mesh data without losing the vertex group names, which may have come
+ * from another object. */
+void MeshComponent::replace_mesh_but_keep_vertex_group_names(Mesh *mesh,
+                                                             GeometryOwnershipType ownership)
+{
+  BLI_assert(this->is_mutable());
+  if (mesh_ != nullptr) {
+    if (ownership_ == GeometryOwnershipType::Owned) {
+      BKE_id_free(nullptr, mesh_);
+    }
+    mesh_ = nullptr;
+  }
+  mesh_ = mesh;
+  ownership_ = ownership;
+}
+
 /* Return the mesh and clear the component. The caller takes over responsibility for freeing the
  * mesh (if the component was responsible before). */
 Mesh *MeshComponent::release()