Render: Update lightgroup membership in objects and world if lightgroup is renamed

As discussed, this only updates objects in and the world of the scene to which the view layer belongs, which also avoids the problem of not having a BMain available.

Differential Revision: https://developer.blender.org/D14740

3 files changed, 29 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_layer.h b/source/blender/blenkernel/BKE_layer.h
index 3e4f2fe154e..9a6c3cf2b5f 100644
--- a/source/blender/blenkernel/BKE_layer.h
+++ b/source/blender/blenkernel/BKE_layer.h
@@ -590,7 +590,8 @@ void BKE_view_layer_set_active_lightgroup(struct ViewLayer *view_layer,
                                           struct ViewLayerLightgroup *lightgroup);
 struct ViewLayer *BKE_view_layer_find_with_lightgroup(
     struct Scene *scene, struct ViewLayerLightgroup *view_layer_lightgroup);
-void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+void BKE_view_layer_rename_lightgroup(struct Scene *scene,
+                                      ViewLayer *view_layer,
                                       ViewLayerLightgroup *lightgroup,
                                       const char *name);
 
diff --git a/source/blender/blenkernel/intern/layer.c b/source/blender/blenkernel/intern/layer.c
index ac582ff69ca..dabc76f29ca 100644
--- a/source/blender/blenkernel/intern/layer.c
+++ b/source/blender/blenkernel/intern/layer.c
@@ -39,6 +39,7 @@
 #include "DNA_view3d_types.h"
 #include "DNA_windowmanager_types.h"
 #include "DNA_workspace_types.h"
+#include "DNA_world_types.h"
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_debug.h"
@@ -2588,12 +2589,36 @@ ViewLayer *BKE_view_layer_find_with_lightgroup(struct Scene *scene,
   return NULL;
 }
 
-void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+void BKE_view_layer_rename_lightgroup(Scene *scene,
+                                      ViewLayer *view_layer,
                                       ViewLayerLightgroup *lightgroup,
                                       const char *name)
 {
+  char old_name[64];
+  BLI_strncpy_utf8(old_name, lightgroup->name, sizeof(old_name));
   BLI_strncpy_utf8(lightgroup->name, name, sizeof(lightgroup->name));
   viewlayer_lightgroup_make_name_unique(view_layer, lightgroup);
+
+  if (scene != NULL) {
+    /* Update objects in the scene to refer to the new name instead. */
+    FOREACH_SCENE_OBJECT_BEGIN (scene, ob) {
+      if (!ID_IS_LINKED(ob) && ob->lightgroup != NULL) {
+        LightgroupMembership *lgm = ob->lightgroup;
+        if (STREQ(lgm->name, old_name)) {
+          BLI_strncpy_utf8(lgm->name, lightgroup->name, sizeof(lgm->name));
+        }
+      }
+    }
+    FOREACH_SCENE_OBJECT_END;
+
+    /* Update the scene's world to refer to the new name instead. */
+    if (scene->world != NULL && !ID_IS_LINKED(scene->world) && scene->world->lightgroup != NULL) {
+      LightgroupMembership *lgm = scene->world->lightgroup;
+      if (STREQ(lgm->name, old_name)) {
+        BLI_strncpy_utf8(lgm->name, lightgroup->name, sizeof(lgm->name));
+      }
+    }
+  }
 }
 
 void BKE_lightgroup_membership_get(struct LightgroupMembership *lgm, char *name)
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index daf4c99845d..f24aec3447b 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -2501,7 +2501,7 @@ static void rna_ViewLayerLightgroup_name_set(PointerRNA *ptr, const char *value)
   Scene *scene = (Scene *)ptr->owner_id;
   ViewLayer *view_layer = BKE_view_layer_find_with_lightgroup(scene, lightgroup);
 
-  BKE_view_layer_rename_lightgroup(view_layer, lightgroup, value);
+  BKE_view_layer_rename_lightgroup(scene, view_layer, lightgroup, value);
 }
 
 /* Fake value, used internally (not saved to DNA). */