Groups and collection: initial integration

Since we are ditching layers from Blender (2.8) we need a replacement to
control groups visibility. This commit introduces collections as the building
blocks for groups, allowing users to control visibility as well as overrides
for groups.

Features
========

* Groups now have collections
    This way you can change the visibility of a collection inside a group, and add
    overrides which are part of the group and are prioritized over other overrides.

* Outliner
    Groups can inspect their collections, change visibility, and add/remove members.

    To change an override of a group collection, you need to select an instance of
    the group, and then you can choose "group" in the collection properties editor
    to edit this group active collection instead of the view layer one.

* Dupli groups overrides
    We can now have multiple instances of the same group with an original "override"
    and different overrides depending on the collection the instanced object is part
    of.

Technical
=========

* Layers
    We use the same api for groups and scene as much as possible.

Reviewers: sergey (depsgraph), mont29 (read/write and user count)
Differential Revision: https://developer.blender.org/D2892

1 files changed, 19 insertions, 10 deletions

diff --git a/source/blender/editors/space_outliner/outliner_collections.c b/source/blender/editors/space_outliner/outliner_collections.c
index adf7e1dc5d3..a32a9c5f523 100644
--- a/source/blender/editors/space_outliner/outliner_collections.c
+++ b/source/blender/editors/space_outliner/outliner_collections.c
@@ -36,6 +36,8 @@
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_build.h"
 
+#include "DNA_group_types.h"
+
 #include "ED_screen.h"
 
 #include "WM_api.h"
@@ -110,7 +112,7 @@ static int collection_link_exec(bContext *C, wmOperator *op)
 {
 	Scene *scene = CTX_data_scene(C);
 	ViewLayer *view_layer = CTX_data_view_layer(C);
-	SceneCollection *sc_master = BKE_collection_master(scene);
+	SceneCollection *sc_master = BKE_collection_master(&scene->id);
 	SceneCollection *sc;
 
 	int scene_collection_index = RNA_enum_get(op->ptr, "scene_collection");
@@ -136,7 +138,9 @@ static int collection_link_exec(bContext *C, wmOperator *op)
 
 static int collection_link_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 {
-	if (BKE_collection_master(CTX_data_scene(C))->scene_collections.first == NULL) {
+	Scene *scene = CTX_data_scene(C);
+	SceneCollection *master_collection = BKE_collection_master(&scene->id);
+	if (master_collection->scene_collections.first == NULL) {
 		RNA_enum_set(op->ptr, "scene_collection", 0);
 		return collection_link_exec(C, op);
 	}
@@ -169,7 +173,7 @@ static const EnumPropertyItem *collection_scene_collection_itemf(
 	int value = 0, totitem = 0;
 
 	Scene *scene = CTX_data_scene(C);
-	SceneCollection *sc = BKE_collection_master(scene);
+	SceneCollection *sc = BKE_collection_master(&scene->id);
 
 	collection_scene_collection_itemf_recursive(&tmp, &item, &totitem, &value, sc);
 	RNA_enum_item_end(&item, &totitem);
@@ -257,15 +261,18 @@ void OUTLINER_OT_collection_unlink(wmOperatorType *ot)
 	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+/**********************************************************************************/
+/* Add new collection. */
+
 static int collection_new_exec(bContext *C, wmOperator *UNUSED(op))
 {
+	Main *bmain = CTX_data_main(C);
 	Scene *scene = CTX_data_scene(C);
 	ViewLayer *view_layer = CTX_data_view_layer(C);
+	SceneCollection *scene_collection = BKE_collection_add(&scene->id, NULL, COLLECTION_TYPE_NONE, NULL);
+	BKE_collection_link(view_layer, scene_collection);
 
-	SceneCollection *sc = BKE_collection_add(scene, NULL, NULL);
-	BKE_collection_link(view_layer, sc);
-
-	DEG_relations_tag_update(CTX_data_main(C));
+	DEG_relations_tag_update(bmain);
 	WM_main_add_notifier(NC_SCENE | ND_LAYER, NULL);
 	return OPERATOR_FINISHED;
 }
@@ -275,7 +282,7 @@ void OUTLINER_OT_collection_new(wmOperatorType *ot)
 	/* identifiers */
 	ot->name = "New Collection";
 	ot->idname = "OUTLINER_OT_collection_new";
-	ot->description = "Add a new collection to the scene, and link it to the active layer";
+	ot->description = "Add a new collection to the scene";
 
 	/* api callbacks */
 	ot->exec = collection_new_exec;
@@ -284,6 +291,8 @@ void OUTLINER_OT_collection_new(wmOperatorType *ot)
 	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+/**********************************************************************************/
+
 /**
  * Returns true is selected element is a collection
  */
@@ -336,12 +345,12 @@ static TreeTraversalAction collection_delete_cb(TreeElement *te, void *customdat
 		return TRAVERSE_SKIP_CHILDS;
 	}
 
-	if (scene_collection == BKE_collection_master(data->scene)) {
+	if (scene_collection == BKE_collection_master(&data->scene->id)) {
 		/* skip - showing warning/error message might be missleading
 		 * when deleting multiple collections, so just do nothing */
 	}
 	else {
-		BKE_collection_remove(data->scene, scene_collection);
+		BKE_collection_remove(&data->scene->id, scene_collection);
 	}
 
 	return TRAVERSE_CONTINUE;