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, 80 insertions, 62 deletions

diff --git a/source/blender/blenkernel/intern/group.c b/source/blender/blenkernel/intern/group.c
index f4555ceac38..7c2eefe657c 100644
--- a/source/blender/blenkernel/intern/group.c
+++ b/source/blender/blenkernel/intern/group.c
@@ -45,32 +45,53 @@
 #include "BLI_blenlib.h"
 #include "BLI_utildefines.h"
 
+#include "BKE_collection.h"
 #include "BKE_global.h"
 #include "BKE_group.h"
 #include "BKE_icons.h"
+#include "BKE_layer.h"
 #include "BKE_library.h"
 #include "BKE_main.h"
 #include "BKE_object.h"
 #include "BKE_scene.h"
 
-static void free_group_object(GroupObject *go)
-{
-	MEM_freeN(go);
-}
-
 /** Free (or release) any data used by this group (does not free the group itself). */
 void BKE_group_free(Group *group)
 {
-	/* don't free group itself */
-	GroupObject *go;
-
 	/* No animdata here. */
+	BKE_previewimg_free(&group->preview);
 
-	while ((go = BLI_pophead(&group->gobject))) {
-		free_group_object(go);
+	if (group->view_layer != NULL) {
+		BKE_view_layer_free(group->view_layer);
+		group->view_layer = NULL;
 	}
 
-	BKE_previewimg_free(&group->preview);
+	if (group->collection != NULL) {
+		BKE_collection_master_free(&group->id, false);
+		MEM_freeN(group->collection);
+		group->collection = NULL;
+	}
+}
+
+/**
+ * Run when adding new groups or during doversion.
+ */
+void BKE_group_init(Group *group)
+{
+	group->collection = MEM_callocN(sizeof(SceneCollection), __func__);
+	BLI_strncpy(group->collection->name, "Master Collection", sizeof(group->collection->name));
+	group->view_layer = NULL; /* groups are not calloced. */
+	group->view_layer = BKE_view_layer_group_add(group);
+
+	/* Unlink the master collection. */
+	BKE_collection_unlink(group->view_layer, group->view_layer->layer_collections.first);
+
+	/* Create and link a new default collection. */
+	SceneCollection *defaut_collection = BKE_collection_add(&group->id,
+	                                                        NULL,
+	                                                        COLLECTION_TYPE_GROUP_INTERNAL,
+	                                                        "Default Collection");
+	BKE_collection_link(group->view_layer, defaut_collection);
 }
 
 Group *BKE_group_add(Main *bmain, const char *name)
@@ -83,7 +104,7 @@ Group *BKE_group_add(Main *bmain, const char *name)
 	group->layer = (1 << 20) - 1;
 
 	group->preview = NULL;
-
+	BKE_group_init(group);
 	return group;
 }
 
@@ -97,7 +118,8 @@ Group *BKE_group_add(Main *bmain, const char *name)
  */
 void BKE_group_copy_data(Main *UNUSED(bmain), Group *group_dst, const Group *group_src, const int flag)
 {
-	BLI_duplicatelist(&group_dst->gobject, &group_src->gobject);
+	/* We never handle usercount here for own data. */
+	const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
 	/* Do not copy group's preview (same behavior as for objects). */
 	if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0 && false) {  /* XXX TODO temp hack */
@@ -106,6 +128,18 @@ void BKE_group_copy_data(Main *UNUSED(bmain), Group *group_dst, const Group *gro
 	else {
 		group_dst->preview = NULL;
 	}
+
+	group_dst->collection = MEM_dupallocN(group_src->collection);
+	SceneCollection *master_collection_src = BKE_collection_master(&group_src->id);
+	SceneCollection *master_collection_dst = BKE_collection_master(&group_dst->id);
+
+	/* Recursively creates a new SceneCollection tree. */
+	BKE_collection_copy_data(master_collection_dst, master_collection_src,
+	                         flag_subdata);
+
+	BKE_view_layer_copy_data(group_dst->view_layer, group_src->view_layer,
+	                          master_collection_dst, master_collection_src,
+	                          flag_subdata);
 }
 
 Group *BKE_group_copy(Main *bmain, const Group *group)
@@ -123,23 +157,19 @@ void BKE_group_make_local(Main *bmain, Group *group, const bool lib_local)
 /* external */
 static bool group_object_add_internal(Group *group, Object *ob)
 {
-	GroupObject *go;
-	
 	if (group == NULL || ob == NULL) {
 		return false;
 	}
-	
-	/* check if the object has been added already */
-	if (BLI_findptr(&group->gobject, ob, offsetof(GroupObject, ob))) {
+
+	/* For now always add to master collection of the group. */
+	SceneCollection *scene_collection = GROUP_MASTER_COLLECTION(group);
+
+	/* If the object has been added already it returns false. */
+	if (BKE_collection_object_add(&group->id, scene_collection, ob) == false) {
 		return false;
 	}
-	
-	go = MEM_callocN(sizeof(GroupObject), "groupobject");
-	BLI_addtail(&group->gobject, go);
-	
-	go->ob = ob;
-	id_us_ensure_real(&go->ob->id);
-	
+
+	id_us_ensure_real(&ob->id);
 	return true;
 }
 
@@ -157,24 +187,17 @@ bool BKE_group_object_add(Group *group, Object *object)
 }
 
 /* also used for (ob == NULL) */
-static int group_object_unlink_internal(Group *group, Object *ob)
+static bool group_object_unlink_internal(Group *group, Object *ob)
 {
-	GroupObject *go, *gon;
-	int removed = 0;
-	if (group == NULL) return 0;
-	
-	go = group->gobject.first;
-	while (go) {
-		gon = go->next;
-		if (go->ob == ob) {
-			BLI_remlink(&group->gobject, go);
-			free_group_object(go);
-			removed = 1;
-			/* should break here since an object being in a group twice cant happen? */
-		}
-		go = gon;
+	if (group == NULL) {
+		return false;
 	}
-	return removed;
+
+	if (BKE_collections_object_remove(NULL, &group->id, ob, false)) {
+		return true;
+	}
+
+	return false;
 }
 
 static bool group_object_cyclic_check_internal(Object *object, Group *group)
@@ -191,12 +214,13 @@ static bool group_object_cyclic_check_internal(Object *object, Group *group)
 		if (dup_group == group)
 			return true;
 		else {
-			GroupObject *gob;
-			for (gob = dup_group->gobject.first; gob; gob = gob->next) {
-				if (group_object_cyclic_check_internal(gob->ob, group)) {
+			FOREACH_GROUP_OBJECT(dup_group, group_object)
+			{
+				if (group_object_cyclic_check_internal(group_object, dup_group)) {
 					return true;
 				}
 			}
+			FOREACH_GROUP_OBJECT_END
 		}
 
 		/* un-flag the object, it's allowed to have the same group multiple times in parallel */
@@ -234,7 +258,7 @@ bool BKE_group_object_exists(Group *group, Object *ob)
 		return false;
 	}
 	else {
-		return (BLI_findptr(&group->gobject, ob, offsetof(GroupObject, ob)) != NULL);
+		return (BLI_findptr(&group->view_layer->object_bases, ob, offsetof(Base, object)));
 	}
 }
 
@@ -255,17 +279,13 @@ Group *BKE_group_object_find(Group *group, Object *ob)
 
 bool BKE_group_is_animated(Group *group, Object *UNUSED(parent))
 {
-	GroupObject *go;
-
-#if 0 /* XXX OLD ANIMSYS, NLASTRIPS ARE NO LONGER USED */
-	if (parent->nlastrips.first)
-		return 1;
-#endif
-
-	for (go = group->gobject.first; go; go = go->next)
-		if (go->ob && go->ob->proxy)
+	FOREACH_GROUP_OBJECT(group, object)
+	{
+		if (object->proxy) {
 			return true;
-
+		}
+	}
+	FOREACH_GROUP_OBJECT_END
 	return false;
 }
 
@@ -317,8 +337,6 @@ static void group_replaces_nla(Object *parent, Object *target, char mode)
 /* note: does not work for derivedmesh and render... it recreates all again in convertblender.c */
 void BKE_group_handle_recalc_and_update(const struct EvaluationContext *eval_ctx, Scene *scene, Object *UNUSED(parent), Group *group)
 {
-	GroupObject *go;
-	
 #if 0 /* warning, isn't clearing the recalc flag on the object which causes it to run all the time,
 	   * not just on frame change.
 	   * This isn't working because the animation data is only re-evaluated on frame change so commenting for now
@@ -352,12 +370,12 @@ void BKE_group_handle_recalc_and_update(const struct EvaluationContext *eval_ctx
 #endif
 	{
 		/* only do existing tags, as set by regular depsgraph */
-		for (go = group->gobject.first; go; go = go->next) {
-			if (go->ob) {
-				if (go->ob->id.tag & LIB_TAG_ID_RECALC_ALL) {
-					BKE_object_handle_update(eval_ctx, scene, go->ob);
-				}
+		FOREACH_GROUP_OBJECT(group, object)
+		{
+			if (object->id.tag & LIB_TAG_ID_RECALC_ALL) {
+				BKE_object_handle_update(eval_ctx, scene, object);
 			}
 		}
+		FOREACH_GROUP_OBJECT_END
 	}
 }