Groups and collection: create group from collection

You could still create groups as before, with Ctl + G. This will create a group
with a single visible collection.

However you can also create a group from an existing collection. Just go to
the menu you get in the outliner when clicking in a collection and pick
"Create Group".

Remember to instance the group afterwards, or link it into a new scene or file.

The group and the collection are not kept in sync afterwards. You need to manually
edit the group for further changes.

9 files changed, 381 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h
index c305a05ddd0..48b4ff881ae 100644
--- a/source/blender/blenkernel/BKE_collection.h
+++ b/source/blender/blenkernel/BKE_collection.h
@@ -58,6 +58,8 @@ bool BKE_collection_object_remove(struct Main *bmain, struct ID *owner_id, struc
 bool BKE_collections_object_remove(struct Main *bmain, struct ID *owner_id, struct Object *object, const bool free_us);
 void BKE_collection_object_move(struct ID *owner_id, struct SceneCollection *sc_dst, struct SceneCollection *sc_src, struct Object *ob);
 
+struct Group *BKE_collection_group_create(struct Main *bmain, struct Scene *scene, struct LayerCollection *lc);
+
 void BKE_collection_reinsert_after(const struct Scene *scene, struct SceneCollection *sc_reinsert, struct SceneCollection *sc_after);
 void BKE_collection_reinsert_into(struct SceneCollection *sc_reinsert, struct SceneCollection *sc_into);
 
diff --git a/source/blender/blenkernel/intern/collection.c b/source/blender/blenkernel/intern/collection.c
index aa5b9e7eb25..8d69563f5ff 100644
--- a/source/blender/blenkernel/intern/collection.c
+++ b/source/blender/blenkernel/intern/collection.c
@@ -34,6 +34,7 @@
 #include "BLI_string_utils.h"
 
 #include "BKE_collection.h"
+#include "BKE_group.h"
 #include "BKE_idprop.h"
 #include "BKE_layer.h"
 #include "BKE_library.h"
@@ -48,6 +49,9 @@
 
 #include "MEM_guardedalloc.h"
 
+/* Prototypes. */
+static bool is_collection_in_tree(const struct SceneCollection *sc_reference, struct SceneCollection *sc_parent);
+
 static SceneCollection *collection_master_from_id(const ID *owner_id)
 {
 	switch (GS(owner_id->name)) {
@@ -407,6 +411,82 @@ bool BKE_collections_object_remove(Main *bmain, ID *owner_id, Object *ob, const
 	return removed;
 }
 
+static void layer_collection_sync(LayerCollection *lc_dst, LayerCollection *lc_src)
+{
+	lc_dst->flag = lc_src->flag;
+
+	/* Pending: sync overrides. */
+	IDP_MergeGroup(lc_dst->properties, lc_src->properties, true);
+
+	/* Continue recursively. */
+	LayerCollection *lc_dst_nested, *lc_src_nested;
+	lc_src_nested = lc_src->layer_collections.first;
+	for (lc_dst_nested = lc_dst->layer_collections.first;
+	     lc_dst_nested && lc_src_nested;
+	     lc_dst_nested = lc_dst_nested->next, lc_src_nested = lc_src_nested->next)
+	{
+		layer_collection_sync(lc_dst_nested, lc_src_nested);
+	}
+}
+
+/**
+ * Leave only the master collection in, remove everything else.
+ * @param group
+ */
+static void collection_group_cleanup(Group *group)
+{
+	/* Unlink all the LayerCollections. */
+	while (group->view_layer->layer_collections.last != NULL) {
+		BKE_collection_unlink(group->view_layer, group->view_layer->layer_collections.last);
+	}
+
+	/* Remove all the SceneCollections but the master. */
+	collection_free(group->collection, false);
+}
+
+/**
+ * Create a group from a collection
+ *
+ * Any ViewLayer that may have this the related SceneCollection linked is converted
+ * to a Group Collection.
+ */
+Group *BKE_collection_group_create(Main *bmain, Scene *scene, LayerCollection *lc_src)
+{
+	SceneCollection *sc_dst, *sc_src = lc_src->scene_collection;
+	LayerCollection *lc_dst;
+
+	/* The master collection can't be converted. */
+	if (sc_src == BKE_collection_master(&scene->id)) {
+		return NULL;
+	}
+
+	/* If a sub-collection of sc_dst is directly linked into a ViewLayer we can't convert. */
+	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+		for (LayerCollection *lc_child = view_layer->layer_collections.first; lc_child; lc_child = lc_child->next) {
+			if (is_collection_in_tree(lc_child->scene_collection, sc_src)) {
+				return NULL;
+			}
+		}
+	}
+
+	/* Create new group with the same data as the original collection. */
+	Group *group = BKE_group_add(bmain, sc_src->name);
+	collection_group_cleanup(group);
+
+	sc_dst = BKE_collection_add(&group->id, NULL, COLLECTION_TYPE_GROUP_INTERNAL, sc_src->name);
+	BKE_collection_copy_data(sc_dst, sc_src, 0);
+	FOREACH_SCENE_COLLECTION(&group->id, sc_group)
+	{
+		sc_group->type = COLLECTION_TYPE_GROUP_INTERNAL;
+	}
+	FOREACH_SCENE_COLLECTION_END
+
+	lc_dst = BKE_collection_link(group->view_layer, sc_dst);
+	layer_collection_sync(lc_dst, lc_src);
+
+	return group;
+}
+
 /* ---------------------------------------------------------------------- */
 /* Outliner drag and drop */
 
diff --git a/source/blender/editors/space_outliner/outliner_tools.c b/source/blender/editors/space_outliner/outliner_tools.c
index 203942b3c9b..99fd539293f 100644
--- a/source/blender/editors/space_outliner/outliner_tools.c
+++ b/source/blender/editors/space_outliner/outliner_tools.c
@@ -664,6 +664,7 @@ typedef enum eOutliner_PropCollectionOps {
 	OL_COLLECTION_OP_COLLECTION_NEW,
 	OL_COLLECTION_OP_COLLECTION_DEL,
 	OL_COLLECTION_OP_COLLECTION_UNLINK,
+	OL_COLLECTION_OP_GROUP_CREATE,
 } eOutliner_PropCollectionOps;
 
 static void pchan_cb(int event, TreeElement *te, TreeStoreElem *UNUSED(tselem), void *UNUSED(arg))
@@ -878,6 +879,17 @@ static void collection_cb(int event, TreeElement *te, TreeStoreElem *UNUSED(tsel
 			TODO_LAYER_OPERATORS; /* this shouldn't be in the menu in those cases */
 		}
 	}
+	else if (event == OL_COLLECTION_OP_GROUP_CREATE) {
+		Main *bmain = CTX_data_main(C);
+		BKE_collection_group_create(bmain, scene, lc);
+		DEG_relations_tag_update(bmain);
+		/* TODO(sergey): Use proper flag for tagging here. */
+		DEG_id_tag_update(&scene->id, 0);
+		WM_event_add_notifier(C, NC_SCENE | ND_LAYER, scene);
+	}
+	else {
+		BLI_assert(!"Collection operation not fully implemented!");
+	}
 }
 
 static void outliner_do_data_operation(SpaceOops *soops, int type, int event, ListBase *lb,
@@ -1808,6 +1820,7 @@ static EnumPropertyItem prop_collection_op_none_types[] = {
 	{OL_COLLECTION_OP_COLLECTION_NEW, "COLLECTION_NEW", ICON_NEW, "New Collection", "Add a new nested collection"},
 	{OL_COLLECTION_OP_COLLECTION_UNLINK, "COLLECTION_UNLINK", ICON_UNLINKED, "Unlink", "Unlink collection"},
 	{OL_COLLECTION_OP_COLLECTION_DEL, "COLLECTION_DEL", ICON_X, "Delete Collection", "Delete the collection"},
+	{OL_COLLECTION_OP_GROUP_CREATE, "GROUP_CREATE", ICON_GROUP, "Create Group", "Turn the collection into a group collection"},
 	{0, NULL, 0, NULL, NULL}
 };
 
diff --git a/source/blender/makesrna/intern/rna_layer.c b/source/blender/makesrna/intern/rna_layer.c
index df6c2188799..557b9a11997 100644
--- a/source/blender/makesrna/intern/rna_layer.c
+++ b/source/blender/makesrna/intern/rna_layer.c
@@ -738,6 +738,32 @@ static void rna_LayerCollection_enable_set(
 	WM_event_add_notifier(C, NC_SCENE | ND_LAYER_CONTENT, scene);
 }
 
+static Group *rna_LayerCollection_create_group(
+        ID *id, LayerCollection *layer_collection, Main *bmain, bContext *C, ReportList *reports)
+{
+	Group *group;
+	Scene *scene = (Scene *)id;
+	SceneCollection *scene_collection = layer_collection->scene_collection;
+
+	/* The master collection can't be converted. */
+	if (scene_collection == BKE_collection_master(&scene->id)) {
+		BKE_report(reports, RPT_ERROR, "The master collection can't be converted to group");
+		return NULL;
+	}
+
+	group = BKE_collection_group_create(bmain, scene, layer_collection);
+	if (group == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "Failed to convert collection %s", scene_collection->name);
+		return NULL;
+	}
+
+	DEG_relations_tag_update(bmain);
+	/* TODO(sergey): Use proper flag for tagging here. */
+	DEG_id_tag_update(&scene->id, 0);
+	WM_event_add_notifier(C, NC_SCENE | ND_LAYER, scene);
+	return group;
+}
+
 static int rna_LayerCollections_active_collection_index_get(PointerRNA *ptr)
 {
 	ViewLayer *view_layer = (ViewLayer *)ptr->data;
@@ -2019,6 +2045,12 @@ static void rna_def_layer_collection(BlenderRNA *brna)
 	parm = RNA_def_boolean(func, "value", 1, "Enable", "");
 	RNA_def_function_flag(func, FUNC_USE_SELF_ID | FUNC_USE_MAIN | FUNC_USE_CONTEXT | FUNC_USE_REPORTS);
 
+	func = RNA_def_function(srna, "create_group", "rna_LayerCollection_create_group");
+	RNA_def_function_ui_description(func, "Enable or disable a collection");
+	RNA_def_function_flag(func, FUNC_USE_SELF_ID | FUNC_USE_MAIN | FUNC_USE_CONTEXT | FUNC_USE_REPORTS);
+	parm = RNA_def_pointer(func, "result", "Group", "", "Newly created Group");
+	RNA_def_function_return(func, parm);
+
 	/* Flags */
 	prop = RNA_def_property(srna, "is_enabled", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_negative_sdna(prop, NULL, "flag", COLLECTION_DISABLED);
diff --git a/tests/python/view_layer/CMakeLists.txt b/tests/python/view_layer/CMakeLists.txt
index e5b271dcb1e..22cfcd344f3 100644
--- a/tests/python/view_layer/CMakeLists.txt
+++ b/tests/python/view_layer/CMakeLists.txt
@@ -87,6 +87,10 @@ VIEW_LAYER_TEST(evaluation_selectability_c)
 VIEW_LAYER_TEST(evaluation_selectability_d)
 VIEW_LAYER_TEST(evaluation_selectability_e)
 VIEW_LAYER_TEST(evaluation_selectability_f)
+VIEW_LAYER_TEST(group_a)
+VIEW_LAYER_TEST(group_b)
+VIEW_LAYER_TEST(group_c)
+VIEW_LAYER_TEST(group_d)
 VIEW_LAYER_TEST(object_add_cylinder)
 VIEW_LAYER_TEST(object_add_empty)
 VIEW_LAYER_TEST(object_add_torus)
diff --git a/tests/python/view_layer/test_group_a.py b/tests/python/view_layer/test_group_a.py
new file mode 100644
index 00000000000..6e1b83efbe5
--- /dev/null
+++ b/tests/python/view_layer/test_group_a.py
@@ -0,0 +1,46 @@
+# ############################################################
+# Importing - Same For All Render Layer Tests
+# ############################################################
+
+import unittest
+import os
+import sys
+
+from view_layer_common import *
+
+
+# ############################################################
+# Testing
+# ############################################################
+
+class UnitTesting(ViewLayerTesting):
+    def test_group_create_basic(self):
+        """
+        See if the creation of new groups is not crashing anything.
+        """
+        import bpy
+        scene = bpy.context.scene
+        layer_collection = bpy.context.layer_collection
+
+        # Cleanup Viewport view layer
+        # technically this shouldn't be needed but
+        # for now we need it because depsgraph build all the view layers
+        # at once.
+
+        while len(scene.view_layers) > 1:
+            scene.view_layers.remove(scene.view_layers[1])
+
+        # create group
+        group = layer_collection.create_group()
+
+        # update depsgraph
+        scene.update()
+
+
+# ############################################################
+# Main - Same For All Render Layer Tests
+# ############################################################
+
+if __name__ == '__main__':
+    UnitTesting._extra_arguments = setup_extra_arguments(__file__)
+    unittest.main()
diff --git a/tests/python/view_layer/test_group_b.py b/tests/python/view_layer/test_group_b.py
new file mode 100644
index 00000000000..6a4478aeba8
--- /dev/null
+++ b/tests/python/view_layer/test_group_b.py
@@ -0,0 +1,72 @@
+# ############################################################
+# Importing - Same For All Render Layer Tests
+# ############################################################
+
+import unittest
+import os
+import sys
+
+from view_layer_common import *
+
+
+# ############################################################
+# Testing
+# ############################################################
+
+class UnitTesting(ViewLayerTesting):
+    def test_group_create_basic(self):
+        """
+        See if the creation of new groups is preserving visibility flags
+        from the original collections.
+        """
+        import bpy
+        scene = bpy.context.scene
+
+        # clean slate
+        self.cleanup_tree()
+
+        master_collection = scene.master_collection
+        grandma = master_collection.collections.new('бабушка')
+        mom = grandma.collections.new('матушка')
+
+        child = bpy.data.objects.new("Child", None)
+        mom.objects.link(child)
+
+        grandma_layer_collection = scene.view_layers[0].collections.link(grandma)
+        mom_layer_collection = grandma_layer_collection.collections[0]
+
+        grandma_layer_collection.hide = False
+        grandma_layer_collection.hide = False
+        mom_layer_collection.hide = True
+        mom_layer_collection.hide_select = False
+
+        # update depsgraph
+        scene.update()
+
+        # create group
+        group = grandma_layer_collection.create_group()
+
+        # update depsgraph
+        scene.update()
+
+        # compare
+        self.assertEqual(len(group.view_layer.collections), 1)
+        grandma_group_layer = group.view_layer.collections[0]
+
+        self.assertEqual(grandma_group_layer.hide, False)
+        self.assertEqual(grandma_group_layer.hide_select, False)
+
+        self.assertEqual(len(grandma_group_layer.collections), 1)
+        mom_group_layer = grandma_group_layer.collections[0]
+
+        self.assertEqual(mom_group_layer.hide, True)
+        self.assertEqual(mom_group_layer.hide_select, False)
+
+
+# ############################################################
+# Main - Same For All Render Layer Tests
+# ############################################################
+
+if __name__ == '__main__':
+    UnitTesting._extra_arguments = setup_extra_arguments(__file__)
+    unittest.main()
diff --git a/tests/python/view_layer/test_group_c.py b/tests/python/view_layer/test_group_c.py
new file mode 100644
index 00000000000..69feab1a56e
--- /dev/null
+++ b/tests/python/view_layer/test_group_c.py
@@ -0,0 +1,56 @@
+# ############################################################
+# Importing - Same For All Render Layer Tests
+# ############################################################
+
+import unittest
+import os
+import sys
+
+from view_layer_common import *
+
+
+# ############################################################
+# Testing
+# ############################################################
+
+class UnitTesting(ViewLayerTesting):
+    def test_group_create_basic(self):
+        """
+        More advanced creation of group from a collection not directly linked
+        to the scene layer.
+        """
+        import bpy
+        scene = bpy.context.scene
+
+        # clean slate
+        self.cleanup_tree()
+
+        children = [bpy.data.objects.new("Child", None) for i in range(3)]
+        master_collection = scene.master_collection
+
+        grandma_scene_collection = master_collection.collections.new('Grand-Mother')
+        mom_scene_collection = grandma_scene_collection.collections.new('Mother')
+
+        grandma_scene_collection.objects.link(children[0])
+        mom_scene_collection.objects.link(children[1])
+
+        grandma_layer_collection = scene.view_layers[0].collections.link(grandma_scene_collection)
+        mom_layer_collection = grandma_layer_collection.collections[mom_scene_collection.name]
+
+        # update depsgraph
+        scene.update()
+
+        # create group
+        group = mom_layer_collection.create_group()
+
+        # update depsgraph
+        scene.update()
+
+
+# ############################################################
+# Main - Same For All Render Layer Tests
+# ############################################################
+
+if __name__ == '__main__':
+    UnitTesting._extra_arguments = setup_extra_arguments(__file__)
+    unittest.main()
diff --git a/tests/python/view_layer/test_group_d.py b/tests/python/view_layer/test_group_d.py
new file mode 100644
index 00000000000..6f54ca5340a
--- /dev/null
+++ b/tests/python/view_layer/test_group_d.py
@@ -0,0 +1,76 @@
+# ############################################################
+# Importing - Same For All Render Layer Tests
+# ############################################################
+
+import unittest
+import os
+import sys
+
+from view_layer_common import *
+
+
+# ############################################################
+# Testing
+# ############################################################
+
+class UnitTesting(ViewLayerTesting):
+    def test_group_write_load(self):
+        """
+        See if saving/loading is working for groups
+        """
+        import bpy
+        scene = bpy.context.scene
+        layer_collection = bpy.context.layer_collection
+
+        while len(scene.view_layers) > 1:
+            scene.view_layers.remove(scene.view_layers[1])
+
+        # create group
+        group = layer_collection.create_group()
+
+        self.assertEqual(1, len(bpy.data.groups))
+        self.assertEqual(1, bpy.data.groups[0].users)
+        self.assertEqual(3, len(bpy.data.groups[0].objects))
+
+        import os
+        import tempfile
+        with tempfile.TemporaryDirectory() as dirpath:
+            filepath = os.path.join(dirpath, 'layers.blend')
+
+            for i in range(3):
+                # save and re-open file
+                bpy.ops.wm.save_mainfile('EXEC_DEFAULT', filepath=filepath)
+                bpy.ops.wm.open_mainfile('EXEC_DEFAULT', filepath=filepath)
+
+                self.assertEqual(1, len(bpy.data.groups))
+                self.assertEqual(1, bpy.data.groups[0].users)
+                self.assertEqual(3, len(bpy.data.groups[0].objects))
+
+
+            # empty the group of objects
+            group = bpy.data.groups[0]
+            while group.objects:
+                group.view_layer.collections[0].collection.objects.unlink(group.objects[0])
+
+            # save and re-open file
+            bpy.ops.wm.save_mainfile('EXEC_DEFAULT', filepath=filepath)
+            bpy.ops.wm.open_mainfile('EXEC_DEFAULT', filepath=filepath)
+
+            self.assertEqual(1, len(bpy.data.groups))
+            self.assertEqual(0, bpy.data.groups[0].users)
+            self.assertEqual(0, len(bpy.data.groups[0].objects))
+
+            # save and re-open file
+            bpy.ops.wm.save_mainfile('EXEC_DEFAULT', filepath=filepath)
+            bpy.ops.wm.open_mainfile('EXEC_DEFAULT', filepath=filepath)
+
+            self.assertEqual(0, len(bpy.data.groups))
+
+
+# ############################################################
+# Main - Same For All Render Layer Tests
+# ############################################################
+
+if __name__ == '__main__':
+    UnitTesting._extra_arguments = setup_extra_arguments(__file__)
+    unittest.main()