Simulation: add depsgraph relations for ids referenced by node tree

I'll really have to refactor `ntreeUpdateTree` soon to avoid scanning
all node trees multiple times.

13 files changed, 287 insertions, 99 deletions

diff --git a/source/blender/blenkernel/BKE_simulation.h b/source/blender/blenkernel/BKE_simulation.h
index 5aa71b6381d..6cbe77e8de3 100644
--- a/source/blender/blenkernel/BKE_simulation.h
+++ b/source/blender/blenkernel/BKE_simulation.h
@@ -32,6 +32,7 @@ void *BKE_simulation_add(struct Main *bmain, const char *name);
 void BKE_simulation_data_update(struct Depsgraph *depsgraph,
                                 struct Scene *scene,
                                 struct Simulation *simulation);
+void BKE_simulation_update_dependencies(struct Simulation *simulation, struct Main *bmain);
 
 SimulationState *BKE_simulation_state_add(Simulation *simulation,
                                           const char *type,
diff --git a/source/blender/blenkernel/intern/node.c b/source/blender/blenkernel/intern/node.c
index 7dbf38657a1..ca1354e9fea 100644
--- a/source/blender/blenkernel/intern/node.c
+++ b/source/blender/blenkernel/intern/node.c
@@ -61,6 +61,7 @@
 #include "BKE_lib_query.h"
 #include "BKE_main.h"
 #include "BKE_node.h"
+#include "BKE_simulation.h"
 
 #include "BLI_ghash.h"
 #include "BLI_threads.h"
@@ -3638,6 +3639,16 @@ void ntreeUpdateAllUsers(Main *main, ID *ngroup)
   FOREACH_NODETREE_END;
 }
 
+static void ntreeUpdateSimulationDependencies(Main *main, bNodeTree *simulation_ntree)
+{
+  FOREACH_NODETREE_BEGIN (main, ntree, owner_id) {
+    if (GS(owner_id->name) == ID_SIM && ntree == simulation_ntree) {
+      BKE_simulation_update_dependencies((Simulation *)owner_id, main);
+    }
+  }
+  FOREACH_NODETREE_END;
+}
+
 void ntreeUpdateTree(Main *bmain, bNodeTree *ntree)
 {
   bNode *node;
@@ -3695,6 +3706,11 @@ void ntreeUpdateTree(Main *bmain, bNodeTree *ntree)
     ntree_validate_links(ntree);
   }
 
+  if (bmain != NULL && ntree->typeinfo == ntreeType_Simulation &&
+      (ntree->id.flag & LIB_EMBEDDED_DATA)) {
+    ntreeUpdateSimulationDependencies(bmain, ntree);
+  }
+
   /* clear update flags */
   for (node = ntree->nodes.first; node; node = node->next) {
     node->update = 0;
diff --git a/source/blender/blenkernel/intern/simulation.cc b/source/blender/blenkernel/intern/simulation.cc
index ac9c13e157c..b1c7f50a2af 100644
--- a/source/blender/blenkernel/intern/simulation.cc
+++ b/source/blender/blenkernel/intern/simulation.cc
@@ -285,6 +285,14 @@ void BKE_simulation_data_update(Depsgraph *depsgraph, Scene *scene, Simulation *
   blender::sim::update_simulation_in_depsgraph(depsgraph, scene, simulation);
 }
 
+void BKE_simulation_update_dependencies(Simulation *simulation, Main *bmain)
+{
+  bool dependencies_changed = blender::sim::update_simulation_dependencies(simulation);
+  if (dependencies_changed) {
+    DEG_relations_tag_update(bmain);
+  }
+}
+
 using StateTypeMap = blender::Map<std::string, std::unique_ptr<SimulationStateType>>;
 
 template<typename T>
diff --git a/source/blender/depsgraph/intern/builder/deg_builder_relations.cc b/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
index 2fb67010bb0..e0e35c88af2 100644
--- a/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
+++ b/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
@@ -2634,6 +2634,25 @@ void DepsgraphRelationBuilder::build_simulation(Simulation *simulation)
   OperationKey nodetree_key(
       &simulation->nodetree->id, NodeType::PARAMETERS, OperationCode::PARAMETERS_EXIT);
   add_relation(nodetree_key, simulation_eval_key, "NodeTree -> Simulation", 0);
+
+  LISTBASE_FOREACH (
+      PersistentDataHandleItem *, handle_item, &simulation->persistent_data_handles) {
+    if (handle_item->id == nullptr) {
+      continue;
+    }
+    build_id(handle_item->id);
+    if (GS(handle_item->id->name) == ID_OB) {
+      Object *object = (Object *)handle_item->id;
+      if (handle_item->flag & SIM_HANDLE_DEPENDS_ON_TRANSFORM) {
+        ComponentKey object_transform_key(&object->id, NodeType::TRANSFORM);
+        add_relation(object_transform_key, simulation_eval_key, "Object Transform -> Simulation");
+      }
+      if (handle_item->flag & SIM_HANDLE_DEPENDS_ON_GEOMETRY) {
+        ComponentKey object_geometry_key(&object->id, NodeType::GEOMETRY);
+        add_relation(object_geometry_key, simulation_eval_key, "Object Geometry -> Simulation");
+      }
+    }
+  }
 }
 
 void DepsgraphRelationBuilder::build_scene_sequencer(Scene *scene)
diff --git a/source/blender/makesdna/DNA_simulation_types.h b/source/blender/makesdna/DNA_simulation_types.h
index 5bb0e50e089..c0be66dcb30 100644
--- a/source/blender/makesdna/DNA_simulation_types.h
+++ b/source/blender/makesdna/DNA_simulation_types.h
@@ -72,7 +72,7 @@ typedef struct PersistentDataHandleItem {
   struct PersistentDataHandleItem *prev;
   struct ID *id;
   int handle;
-  char _pad[4];
+  int flag;
 } PersistentDataHandleItem;
 
 /* Simulation.flag */
@@ -80,6 +80,12 @@ enum {
   SIM_DS_EXPAND = (1 << 0),
 };
 
+/* PersistentDataHandleItem.flag */
+enum {
+  SIM_HANDLE_DEPENDS_ON_TRANSFORM = (1 << 0),
+  SIM_HANDLE_DEPENDS_ON_GEOMETRY = (1 << 1),
+};
+
 #define SIM_TYPE_NAME_PARTICLE_SIMULATION "Particle Simulation"
 #define SIM_TYPE_NAME_PARTICLE_MESH_EMITTER "Particle Mesh Emitter"
 
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 6f0192bb810..0359b2ed959 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -38,6 +38,7 @@
 #include "BKE_animsys.h"
 #include "BKE_image.h"
 #include "BKE_node.h"
+#include "BKE_simulation.h"
 #include "BKE_texture.h"
 
 #include "RNA_access.h"
@@ -2848,6 +2849,14 @@ static void rna_NodeSocketStandard_value_update(struct bContext *C, PointerRNA *
   }
 }
 
+static void rna_NodeSocketStandard_value_and_relation_update(struct bContext *C, PointerRNA *ptr)
+{
+  rna_NodeSocketStandard_value_update(C, ptr);
+  bNodeTree *ntree = (bNodeTree *)ptr->owner_id;
+  Main *bmain = CTX_data_main(C);
+  ntreeUpdateTree(bmain, ntree);
+}
+
 /* ******** Node Types ******** */
 
 static void rna_NodeInternalSocketTemplate_name_get(PointerRNA *ptr, char *value)
@@ -8862,7 +8871,8 @@ static void rna_def_node_socket_object(BlenderRNA *brna,
   RNA_def_property_pointer_sdna(prop, NULL, "value");
   RNA_def_property_struct_type(prop, "Object");
   RNA_def_property_ui_text(prop, "Default Value", "Input value used for unconnected socket");
-  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_NodeSocketStandard_value_update");
+  RNA_def_property_update(
+      prop, NC_NODE | NA_EDITED, "rna_NodeSocketStandard_value_and_relation_update");
   RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_REFCOUNT | PROP_CONTEXT_UPDATE);
 
   /* socket interface */
@@ -8896,7 +8906,8 @@ static void rna_def_node_socket_image(BlenderRNA *brna,
   RNA_def_property_pointer_sdna(prop, NULL, "value");
   RNA_def_property_struct_type(prop, "Image");
   RNA_def_property_ui_text(prop, "Default Value", "Input value used for unconnected socket");
-  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_NodeSocketStandard_value_update");
+  RNA_def_property_update(
+      prop, NC_NODE | NA_EDITED, "rna_NodeSocketStandard_value_and_relation_update");
   RNA_def_property_flag(prop, PROP_EDITABLE | PROP_ID_REFCOUNT | PROP_CONTEXT_UPDATE);
 
   /* socket interface */
diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 80720f5206a..bb2aaf35e52 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -278,6 +278,7 @@ set(SRC
   intern/node_common.c
   intern/node_exec.c
   intern/node_socket.cc
+  intern/node_tree_dependencies.cc
   intern/node_tree_multi_function.cc
   intern/node_tree_ref.cc
   intern/node_util.c
@@ -292,6 +293,7 @@ set(SRC
   NOD_composite.h
   NOD_derived_node_tree.hh
   NOD_function.h
+  NOD_node_tree_dependencies.hh
   NOD_node_tree_multi_function.hh
   NOD_node_tree_ref.hh
   NOD_shader.h
diff --git a/source/blender/nodes/NOD_node_tree_dependencies.hh b/source/blender/nodes/NOD_node_tree_dependencies.hh
new file mode 100644
index 00000000000..ca7059caa5f
--- /dev/null
+++ b/source/blender/nodes/NOD_node_tree_dependencies.hh
@@ -0,0 +1,79 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __NOD_NODE_TREE_DEPENDENCIES_H__
+#define __NOD_NODE_TREE_DEPENDENCIES_H__
+
+#include "BLI_vector_set.hh"
+
+#include "DNA_ID.h"
+#include "DNA_object_types.h"
+
+struct bNodeTree;
+
+namespace blender::nodes {
+
+class NodeTreeDependencies {
+ private:
+  VectorSet<Object *> transform_deps_;
+  VectorSet<Object *> geometry_deps_;
+  VectorSet<ID *> id_deps_;
+
+ public:
+  void add_transform_dependency(Object *object)
+  {
+    if (object == nullptr) {
+      return;
+    }
+    transform_deps_.add(object);
+    id_deps_.add(&object->id);
+  }
+
+  void add_geometry_dependency(Object *object)
+  {
+    if (object == nullptr) {
+      return;
+    }
+    geometry_deps_.add(object);
+    id_deps_.add(&object->id);
+  }
+
+  bool depends_on(ID *id) const
+  {
+    return id_deps_.contains(id);
+  }
+
+  Span<Object *> transform_dependencies()
+  {
+    return transform_deps_;
+  }
+
+  Span<Object *> geometry_dependencies()
+  {
+    return geometry_deps_;
+  }
+
+  Span<ID *> id_dependencies()
+  {
+    return id_deps_;
+  }
+};
+
+NodeTreeDependencies find_node_tree_dependencies(bNodeTree &ntree);
+
+}  // namespace blender::nodes
+
+#endif /* __NOD_NODE_TREE_DEPENDENCIES_H__ */
diff --git a/source/blender/nodes/intern/node_tree_dependencies.cc b/source/blender/nodes/intern/node_tree_dependencies.cc
new file mode 100644
index 00000000000..efe75a10f7e
--- /dev/null
+++ b/source/blender/nodes/intern/node_tree_dependencies.cc
@@ -0,0 +1,57 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "NOD_node_tree_dependencies.hh"
+
+#include "DNA_node_types.h"
+
+#include "BKE_node.h"
+
+namespace blender::nodes {
+
+static void add_dependencies_of_node_tree(bNodeTree &ntree, NodeTreeDependencies &r_dependencies)
+{
+  /* TODO: Do a bit more sophisticated parsing to see which dependencies are really required. */
+  LISTBASE_FOREACH (bNode *, node, &ntree.nodes) {
+    LISTBASE_FOREACH (bNodeSocket *, socket, &node->inputs) {
+      if (socket->type == SOCK_OBJECT) {
+        Object *object = ((bNodeSocketValueObject *)socket->default_value)->value;
+        if (object != nullptr) {
+          r_dependencies.add_transform_dependency(object);
+          if (object->type == OB_MESH) {
+            r_dependencies.add_geometry_dependency(object);
+          }
+        }
+      }
+    }
+
+    if (node->type == NODE_GROUP) {
+      bNodeTree *group = (bNodeTree *)node->id;
+      if (group != nullptr) {
+        add_dependencies_of_node_tree(*group, r_dependencies);
+      }
+    }
+  }
+}
+
+NodeTreeDependencies find_node_tree_dependencies(bNodeTree &ntree)
+{
+  NodeTreeDependencies dependencies;
+  add_dependencies_of_node_tree(ntree, dependencies);
+  return dependencies;
+}
+
+}  // namespace blender::nodes
diff --git a/source/blender/simulation/SIM_simulation_update.hh b/source/blender/simulation/SIM_simulation_update.hh
index 40b62bfb58a..efdfde8a4de 100644
--- a/source/blender/simulation/SIM_simulation_update.hh
+++ b/source/blender/simulation/SIM_simulation_update.hh
@@ -27,6 +27,8 @@ void update_simulation_in_depsgraph(Depsgraph *depsgraph,
                                     Scene *scene_cow,
                                     Simulation *simulation_cow);
 
-}
+bool update_simulation_dependencies(Simulation *simulation);
+
+}  // namespace blender::sim
 
 #endif /* __SIM_SIMULATION_UPDATE_HH__ */
diff --git a/source/blender/simulation/intern/simulation_collect_influences.cc b/source/blender/simulation/intern/simulation_collect_influences.cc
index bbc28077dff..876d0b50fc1 100644
--- a/source/blender/simulation/intern/simulation_collect_influences.cc
+++ b/source/blender/simulation/intern/simulation_collect_influences.cc
@@ -436,28 +436,10 @@ static void prepare_particle_attribute_builders(nodes::MFNetworkTreeMap &network
   }
 }
 
-static void find_used_persistent_data(const nodes::DerivedNodeTree &tree,
-                                      UsedPersistentData &r_used_persistent_data)
-{
-  const bNodeSocketType *socktype = nodeSocketTypeFind("NodeSocketObject");
-  BLI_assert(socktype != nullptr);
-
-  for (const nodes::DInputSocket *dsocket : tree.input_sockets()) {
-    const bNodeSocket *bsocket = dsocket->bsocket();
-    if (bsocket->typeinfo == socktype) {
-      Object *object = ((const bNodeSocketValueObject *)bsocket->default_value)->value;
-      if (object != nullptr) {
-        r_used_persistent_data.add(DEG_get_original_id(&object->id));
-      }
-    }
-  }
-}
-
 void collect_simulation_influences(Simulation &simulation,
                                    ResourceCollector &resources,
                                    SimulationInfluences &r_influences,
-                                   RequiredStates &r_required_states,
-                                   UsedPersistentData &r_used_persistent_data)
+                                   RequiredStates &r_required_states)
 {
   nodes::NodeTreeRefMap tree_refs;
   const nodes::DerivedNodeTree tree{simulation.nodetree, tree_refs};
@@ -481,8 +463,6 @@ void collect_simulation_influences(Simulation &simulation,
   for (const nodes::DNode *dnode : get_particle_simulation_nodes(tree)) {
     r_required_states.add(dnode_to_path(*dnode), SIM_TYPE_NAME_PARTICLE_SIMULATION);
   }
-
-  find_used_persistent_data(tree, r_used_persistent_data);
 }
 
 }  // namespace blender::sim
diff --git a/source/blender/simulation/intern/simulation_collect_influences.hh b/source/blender/simulation/intern/simulation_collect_influences.hh
index 13744c3bc1a..42cbea6977e 100644
--- a/source/blender/simulation/intern/simulation_collect_influences.hh
+++ b/source/blender/simulation/intern/simulation_collect_influences.hh
@@ -58,29 +58,10 @@ class RequiredStates {
   }
 };
 
-class UsedPersistentData {
- private:
-  VectorSet<ID *> used_ids_;
-
- public:
-  void add(ID *id)
-  {
-    BLI_assert(id != nullptr);
-    BLI_assert((id->tag & LIB_TAG_NO_MAIN) == 0);
-    used_ids_.add(id);
-  }
-
-  const VectorSet<ID *> &used_ids() const
-  {
-    return used_ids_;
-  }
-};
-
 void collect_simulation_influences(Simulation &simulation,
                                    ResourceCollector &resources,
                                    SimulationInfluences &r_influences,
-                                   RequiredStates &r_required_states,
-                                   UsedPersistentData &r_used_persistent_data);
+                                   RequiredStates &r_required_states);
 
 }  // namespace blender::sim
 
diff --git a/source/blender/simulation/intern/simulation_update.cc b/source/blender/simulation/intern/simulation_update.cc
index 9258d9cac07..3303145b891 100644
--- a/source/blender/simulation/intern/simulation_update.cc
+++ b/source/blender/simulation/intern/simulation_update.cc
@@ -33,6 +33,8 @@
 #include "BLI_set.hh"
 #include "BLI_vector.hh"
 
+#include "NOD_node_tree_dependencies.hh"
+
 #include "particle_function.hh"
 #include "simulation_collect_influences.hh"
 #include "simulation_solver.hh"
@@ -90,56 +92,6 @@ static void update_simulation_state_list(Simulation *simulation,
   add_missing_states(simulation, required_states);
 }
 
-/* TODO: It might be better to do this as part of ntreeUpdateTree, so that the information
- * about referenced data blocks is available when building the depsgraph. */
-static void update_persistent_data_handles(Simulation &simulation_orig,
-                                           const UsedPersistentData &used_persistent_data)
-{
-  Set<ID *> contained_ids;
-  Set<int> used_handles;
-
-  /* Remove handles that have been invalidated. */
-  LISTBASE_FOREACH_MUTABLE (
-      PersistentDataHandleItem *, handle_item, &simulation_orig.persistent_data_handles) {
-    if (handle_item->id == nullptr) {
-      BLI_remlink(&simulation_orig.persistent_data_handles, handle_item);
-      MEM_freeN(handle_item);
-      continue;
-    }
-    if (!used_persistent_data.used_ids().contains(handle_item->id)) {
-      id_us_min(handle_item->id);
-      BLI_remlink(&simulation_orig.persistent_data_handles, handle_item);
-      MEM_freeN(handle_item);
-      continue;
-    }
-    contained_ids.add_new(handle_item->id);
-    used_handles.add_new(handle_item->handle);
-  }
-
-  /* Add new handles that are not in the list yet. */
-  int next_handle = 0;
-  for (ID *id : used_persistent_data.used_ids()) {
-    if (contained_ids.contains(id)) {
-      continue;
-    }
-
-    /* Find the next available handle. */
-    while (used_handles.contains(next_handle)) {
-      next_handle++;
-    }
-    used_handles.add_new(next_handle);
-
-    PersistentDataHandleItem *handle_item = (PersistentDataHandleItem *)MEM_callocN(
-        sizeof(*handle_item), AT);
-    /* Cannot store const pointers in DNA. */
-    id_us_plus(id);
-    handle_item->id = id;
-    handle_item->handle = next_handle;
-
-    BLI_addtail(&simulation_orig.persistent_data_handles, handle_item);
-  }
-}
-
 void update_simulation_in_depsgraph(Depsgraph *depsgraph,
                                     Scene *scene_cow,
                                     Simulation *simulation_cow)
@@ -159,11 +111,8 @@ void update_simulation_in_depsgraph(Depsgraph *depsgraph,
   ResourceCollector resources;
   SimulationInfluences influences;
   RequiredStates required_states;
-  UsedPersistentData used_persistent_data;
 
-  collect_simulation_influences(
-      *simulation_cow, resources, influences, required_states, used_persistent_data);
-  update_persistent_data_handles(*simulation_orig, used_persistent_data);
+  collect_simulation_influences(*simulation_cow, resources, influences, required_states);
 
   bke::PersistentDataHandleMap handle_map;
   LISTBASE_FOREACH (
@@ -191,4 +140,81 @@ void update_simulation_in_depsgraph(Depsgraph *depsgraph,
   }
 }
 
+/* Returns true when dependencies have changed. */
+bool update_simulation_dependencies(Simulation *simulation)
+{
+  nodes::NodeTreeDependencies dependencies = nodes::find_node_tree_dependencies(
+      *simulation->nodetree);
+
+  ListBase *handle_list = &simulation->persistent_data_handles;
+
+  bool dependencies_changed = false;
+
+  Map<ID *, PersistentDataHandleItem *> handle_item_by_id;
+  Map<PersistentDataHandleItem *, int> old_flag_by_handle_item;
+  Set<int> used_handles;
+
+  /* Remove unused handle items and clear flags that are reinitialized later. */
+  LISTBASE_FOREACH_MUTABLE (PersistentDataHandleItem *, handle_item, handle_list) {
+    if (dependencies.depends_on(handle_item->id)) {
+      handle_item_by_id.add_new(handle_item->id, handle_item);
+      used_handles.add_new(handle_item->handle);
+      old_flag_by_handle_item.add_new(handle_item, handle_item->flag);
+      handle_item->flag &= ~(SIM_HANDLE_DEPENDS_ON_TRANSFORM | SIM_HANDLE_DEPENDS_ON_GEOMETRY);
+    }
+    else {
+      if (handle_item->id != nullptr) {
+        id_us_min(handle_item->id);
+      }
+      BLI_remlink(handle_list, handle_item);
+      MEM_freeN(handle_item);
+      dependencies_changed = true;
+    }
+  }
+
+  /* Add handle items for new id dependencies. */
+  int next_handle = 0;
+  for (ID *id : dependencies.id_dependencies()) {
+    handle_item_by_id.lookup_or_add_cb(id, [&]() {
+      while (used_handles.contains(next_handle)) {
+        next_handle++;
+      }
+      used_handles.add_new(next_handle);
+
+      PersistentDataHandleItem *handle_item = (PersistentDataHandleItem *)MEM_callocN(
+          sizeof(*handle_item), AT);
+      id_us_plus(id);
+      handle_item->id = id;
+      handle_item->handle = next_handle;
+      BLI_addtail(handle_list, handle_item);
+
+      return handle_item;
+    });
+  }
+
+  /* Set appropriate dependency flags. */
+  for (Object *object : dependencies.transform_dependencies()) {
+    PersistentDataHandleItem *handle_item = handle_item_by_id.lookup(&object->id);
+    handle_item->flag |= SIM_HANDLE_DEPENDS_ON_TRANSFORM;
+  }
+  for (Object *object : dependencies.geometry_dependencies()) {
+    PersistentDataHandleItem *handle_item = handle_item_by_id.lookup(&object->id);
+    handle_item->flag |= SIM_HANDLE_DEPENDS_ON_GEOMETRY;
+  }
+
+  if (!dependencies_changed) {
+    /* Check if any flags have changed. */
+    LISTBASE_FOREACH (PersistentDataHandleItem *, handle_item, handle_list) {
+      int old_flag = old_flag_by_handle_item.lookup_default(handle_item, 0);
+      int new_flag = handle_item->flag;
+      if (old_flag != new_flag) {
+        dependencies_changed = true;
+        break;
+      }
+    }
+  }
+
+  return dependencies_changed;
+}
+
 }  // namespace blender::sim