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, 27 insertions, 13 deletions

diff --git a/source/blender/editors/space_outliner/outliner_draw.c b/source/blender/editors/space_outliner/outliner_draw.c
index 8b4ed61f148..4ac5ad6e8d2 100644
--- a/source/blender/editors/space_outliner/outliner_draw.c
+++ b/source/blender/editors/space_outliner/outliner_draw.c
@@ -250,9 +250,16 @@ static void restrictbutton_gp_layer_flag_cb(bContext *C, void *UNUSED(poin), voi
 static void enablebutton_collection_flag_cb(bContext *C, void *poin, void *poin2)
 {
 	Main *bmain = CTX_data_main(C);
-	Scene *scene = poin;
+	Scene *scene = CTX_data_scene(C);
+	ID *id = poin;
 	LayerCollection *layer_collection = poin2;
-	ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, layer_collection);
+	ViewLayer *view_layer = BKE_view_layer_find_from_collection(id, layer_collection);
+
+	/* TODO: This breaks when you see the collections of a group. (dfelinto) */
+	if (view_layer == NULL) {
+		WM_reportf(RPT_INFO, "Enable/disable of group collections disabled for now");
+		return;
+	}
 
 	/* We need to toggle the flag since this is called after the flag is already set. */
 	layer_collection->flag ^= COLLECTION_DISABLED;
@@ -273,11 +280,16 @@ static void enablebutton_collection_flag_cb(bContext *C, void *poin, void *poin2
 
 static void restrictbutton_collection_flag_cb(bContext *C, void *poin, void *UNUSED(poin2))
 {
-	Scene *scene = poin;
+	ID *id = (ID *)poin;
+
 	/* hide and deselect bases that are directly influenced by this LayerCollection */
 	/* TODO(sergey): Use proper flag for tagging here. */
-	DEG_id_tag_update(&scene->id, 0);
-	WM_event_add_notifier(C, NC_SCENE | ND_OB_SELECT, scene);
+	DEG_id_tag_update(id, 0);
+
+	if (GS(id->name) == ID_SCE) {
+		WM_event_add_notifier(C, NC_SCENE | ND_OB_SELECT, id);
+	}
+
 	WM_event_add_notifier(C, NC_SCENE | ND_LAYER_CONTENT, NULL);
 }
 
@@ -595,22 +607,24 @@ static void outliner_draw_restrictbuts(uiBlock *block, Scene *scene, ARegion *ar
 				                      (int)(ar->v2d.cur.xmax - OL_TOG_RESTRICT_ENABLEX), te->ys, UI_UNIT_X,
 				                      UI_UNIT_Y, &collection->flag, 0, 0, 0, 0,
 				                      TIP_("Enable/Disable collection from depsgraph"));
-				UI_but_func_set(bt, enablebutton_collection_flag_cb, scene, collection);
+				UI_but_func_set(bt, enablebutton_collection_flag_cb, tselem->id, collection);
 				UI_but_flag_enable(bt, UI_BUT_DRAG_LOCK);
 
 				bt = uiDefIconButBitS(block, UI_BTYPE_ICON_TOGGLE_N, COLLECTION_VISIBLE, 0, ICON_RESTRICT_VIEW_OFF,
 				                      (int)(ar->v2d.cur.xmax - OL_TOG_RESTRICT_VIEWX), te->ys, UI_UNIT_X,
 				                      UI_UNIT_Y, &collection->flag, 0, 0, 0, 0,
 				                      TIP_("Restrict/Allow 3D View visibility of objects in the collection"));
-				UI_but_func_set(bt, restrictbutton_collection_flag_cb, scene, collection);
+				UI_but_func_set(bt, restrictbutton_collection_flag_cb, tselem->id, collection);
 				UI_but_flag_enable(bt, UI_BUT_DRAG_LOCK);
 
-				bt = uiDefIconButBitS(block, UI_BTYPE_ICON_TOGGLE_N, COLLECTION_SELECTABLE, 0, ICON_RESTRICT_SELECT_OFF,
-				                      (int)(ar->v2d.cur.xmax - OL_TOG_RESTRICT_SELECTX), te->ys, UI_UNIT_X,
-				                      UI_UNIT_Y, &collection->flag, 0, 0, 0, 0,
-				                      TIP_("Restrict/Allow 3D View selection of objects in the collection"));
-				UI_but_func_set(bt, restrictbutton_collection_flag_cb, scene, collection);
-				UI_but_flag_enable(bt, UI_BUT_DRAG_LOCK);
+				if (collection->scene_collection->type == COLLECTION_TYPE_NONE) {
+					bt = uiDefIconButBitS(block, UI_BTYPE_ICON_TOGGLE_N, COLLECTION_SELECTABLE, 0, ICON_RESTRICT_SELECT_OFF,
+										  (int)(ar->v2d.cur.xmax - OL_TOG_RESTRICT_SELECTX), te->ys, UI_UNIT_X,
+										  UI_UNIT_Y, &collection->flag, 0, 0, 0, 0,
+										  TIP_("Restrict/Allow 3D View selection of objects in the collection"));
+					UI_but_func_set(bt, restrictbutton_collection_flag_cb, scene, collection);
+					UI_but_flag_enable(bt, UI_BUT_DRAG_LOCK);
+				}
 
 				UI_block_emboss_set(block, UI_EMBOSS);
 			}