Collections: Operator to duplicate a collection

When duplicating a layer collection directly linked to the view layer we copy
the collection and link it.

For all the not directly linked layer collectionns, we try to sync the layer
collection flags, overrides, ...

Also we make sure the new collection is right after the original collection.

We also expose this in RNA, via collection.duplicate().

1 files changed, 50 insertions, 5 deletions

diff --git a/source/blender/blenkernel/intern/collection.c b/source/blender/blenkernel/intern/collection.c
index ca77969ccaa..729be02bfc7 100644
--- a/source/blender/blenkernel/intern/collection.c
+++ b/source/blender/blenkernel/intern/collection.c
@@ -68,10 +68,9 @@ static SceneCollection *collection_master_from_id(const ID *owner_id)
 }
 
 /**
- * Add a collection to a collection ListBase and syncronize all render layers
- * The ListBase is NULL when the collection is to be added to the master collection
+ * Add a new collection, but don't handle syncing with layer collections
  */
-SceneCollection *BKE_collection_add(ID *owner_id, SceneCollection *sc_parent, const int type, const char *name_custom)
+static SceneCollection *collection_add(ID *owner_id, SceneCollection *sc_parent, const int type, const char *name_custom)
 {
 	SceneCollection *sc_master = collection_master_from_id(owner_id);
 	SceneCollection *sc = MEM_callocN(sizeof(SceneCollection), "New Collection");
@@ -99,8 +98,6 @@ SceneCollection *BKE_collection_add(ID *owner_id, SceneCollection *sc_parent, co
 	BLI_addtail(&sc_parent->scene_collections, sc);
 	BKE_collection_rename((Scene *)owner_id, sc, name);
 
-	BKE_layer_sync_new_scene_collection(owner_id, sc_parent, sc);
-
 	if (name != name_custom) {
 		MEM_freeN((char *)name);
 	}
@@ -109,6 +106,17 @@ SceneCollection *BKE_collection_add(ID *owner_id, SceneCollection *sc_parent, co
 }
 
 /**
+ * Add a collection to a collection ListBase and syncronize all render layers
+ * The ListBase is NULL when the collection is to be added to the master collection
+ */
+SceneCollection *BKE_collection_add(ID *owner_id, SceneCollection *sc_parent, const int type, const char *name_custom)
+{
+	SceneCollection *scene_collection = collection_add(owner_id, sc_parent, type, name_custom);
+	BKE_layer_sync_new_scene_collection(owner_id, sc_parent, scene_collection);
+	return scene_collection;
+}
+
+/**
  * Free the collection items recursively
  */
 static void collection_free(SceneCollection *sc, const bool do_id_user)
@@ -270,6 +278,43 @@ void BKE_collection_copy_data(SceneCollection *sc_dst, SceneCollection *sc_src,
 	}
 }
 
+/**
+ * Makes a shallow copy of a SceneCollection
+ *
+ * Add a new collection in the same level as the old one, copy any nested collections
+ * but link the objects to the new collection (as oppose to copy them).
+ */
+SceneCollection *BKE_collection_duplicate(ID *owner_id, SceneCollection *scene_collection)
+{
+	SceneCollection *scene_collection_master = BKE_collection_master(owner_id);
+	SceneCollection *scene_collection_parent = find_collection_parent(scene_collection, scene_collection_master);
+
+	/* It's not allowed to copy the master collection. */
+	if (scene_collection_master == scene_collection) {
+		return NULL;
+	}
+
+	SceneCollection *scene_collection_new = collection_add(
+	                                            owner_id,
+	                                            scene_collection_parent,
+	                                            scene_collection->type,
+	                                            scene_collection->name);
+
+	if (scene_collection_new != scene_collection->next) {
+		BLI_remlink(&scene_collection_parent->scene_collections, scene_collection_new);
+		BLI_insertlinkafter(&scene_collection_parent->scene_collections, scene_collection, scene_collection_new);
+	}
+
+	BKE_collection_copy_data(scene_collection_new, scene_collection, 0);
+	BKE_layer_sync_new_scene_collection(owner_id, scene_collection_parent, scene_collection_new);
+
+	/* Make sure every linked instance of the new collection has the same values (flags, overrides, ...) as the
+	 * corresponding original collection. */
+	BKE_layer_collection_sync_flags(owner_id, scene_collection_new, scene_collection);
+
+	return scene_collection_new;
+}
+
 static SceneCollection *master_collection_from_id(const ID *owner_id)
 {
 	switch (GS(owner_id->name)) {