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, 215 insertions, 49 deletions

diff --git a/source/blender/blenkernel/intern/layer.c b/source/blender/blenkernel/intern/layer.c
index f841181f7c4..363dc53496f 100644
--- a/source/blender/blenkernel/intern/layer.c
+++ b/source/blender/blenkernel/intern/layer.c
@@ -35,12 +35,14 @@
 #include "BKE_collection.h"
 #include "BKE_freestyle.h"
 #include "BKE_global.h"
+#include "BKE_group.h"
 #include "BKE_idprop.h"
 #include "BKE_layer.h"
 #include "BKE_main.h"
 #include "BKE_node.h"
 #include "BKE_workspace.h"
 
+#include "DNA_group_types.h"
 #include "DNA_ID.h"
 #include "DNA_layer_types.h"
 #include "DNA_object_types.h"
@@ -102,11 +104,7 @@ ViewLayer *BKE_view_layer_context_active_PLACEHOLDER(const Scene *scene)
 	return BKE_view_layer_from_scene_get(scene);
 }
 
-/**
- * Add a new renderlayer
- * by default, a renderlayer has the master collection
- */
-ViewLayer *BKE_view_layer_add(Scene *scene, const char *name)
+static ViewLayer *view_layer_add(const char *name, SceneCollection *master_scene_collection)
 {
 	if (!name) {
 		name = DATA_("View Layer");
@@ -118,15 +116,10 @@ ViewLayer *BKE_view_layer_add(Scene *scene, const char *name)
 
 	view_layer->properties = IDP_New(IDP_GROUP, &val, ROOT_PROP);
 	layer_engine_settings_init(view_layer->properties, false);
-
-	BLI_addtail(&scene->view_layers, view_layer);
-
-	/* unique name */
 	BLI_strncpy_utf8(view_layer->name, name, sizeof(view_layer->name));
-	BLI_uniquename(&scene->view_layers, view_layer, DATA_("ViewLayer"), '.', offsetof(ViewLayer, name), sizeof(view_layer->name));
 
-	SceneCollection *sc = BKE_collection_master(scene);
-	layer_collection_add(view_layer, NULL, sc);
+	/* Link the master collection by default. */
+	layer_collection_add(view_layer, NULL, master_scene_collection);
 
 	/* Pure rendering pipeline settings. */
 	view_layer->layflag = 0x7FFF;   /* solid ztra halo edge strand */
@@ -138,6 +131,35 @@ ViewLayer *BKE_view_layer_add(Scene *scene, const char *name)
 }
 
 /**
+ * Add a new view layer
+ * by default, a view layer has the master collection
+ */
+ViewLayer *BKE_view_layer_add(Scene *scene, const char *name)
+{
+	SceneCollection *sc = BKE_collection_master(&scene->id);
+	ViewLayer *view_layer = view_layer_add(name, sc);
+
+	BLI_addtail(&scene->view_layers, view_layer);
+
+	/* unique name */
+	BLI_uniquename(&scene->view_layers, view_layer, DATA_("ViewLayer"), '.', offsetof(ViewLayer, name), sizeof(view_layer->name));
+
+	return view_layer;
+}
+
+/**
+ * Add a ViewLayer for a Group
+ * It should be added only once
+ */
+ViewLayer *BKE_view_layer_group_add(Group *group)
+{
+	BLI_assert(group->view_layer == NULL);
+	SceneCollection *sc = BKE_collection_master(&group->id);
+	ViewLayer *view_layer = view_layer_add(group->id.name + 2, sc);
+	return view_layer;
+}
+
+/**
  * Free (or release) any data used by this ViewLayer.
  */
 void BKE_view_layer_free(ViewLayer *view_layer)
@@ -204,6 +226,22 @@ void BKE_view_layer_selected_objects_tag(ViewLayer *view_layer, const int tag)
 	}
 }
 
+/**
+ * Return the first ViewLayer for a given id
+ */
+ViewLayer *BKE_view_layer_first_from_id(const ID *owner_id)
+{
+	switch (GS(owner_id->name)) {
+		case ID_SCE:
+			return ((Scene *)owner_id)->view_layers.first;
+		case ID_GR:
+			return ((Group *)owner_id)->view_layer;
+		default:
+			BLI_assert(!"ID doesn't support view layers");
+			return NULL;
+	}
+}
+
 static bool find_scene_collection_in_scene_collections(ListBase *lb, const LayerCollection *lc)
 {
 	for (LayerCollection *lcn = lb->first; lcn; lcn = lcn->next) {
@@ -238,14 +276,25 @@ Object *BKE_view_layer_camera_find(ViewLayer *view_layer)
 /**
  * Find the ViewLayer a LayerCollection belongs to
  */
-ViewLayer *BKE_view_layer_find_from_collection(const Scene *scene, LayerCollection *lc)
-{
-	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
-		if (find_scene_collection_in_scene_collections(&view_layer->layer_collections, lc)) {
-			return view_layer;
+ViewLayer *BKE_view_layer_find_from_collection(const ID *owner_id, LayerCollection *lc)
+{
+	switch (GS(owner_id->name)) {
+		case ID_GR:
+			return ((Group *)owner_id)->view_layer;
+		case ID_SCE:
+		{
+			Scene *scene = (Scene *)owner_id;
+			for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+				if (find_scene_collection_in_scene_collections(&view_layer->layer_collections, lc)) {
+					return view_layer;
+				}
+			}
+			return NULL;
 		}
+		default:
+			BLI_assert(!"ID doesn't support scene layers");
+			return NULL;
 	}
-	return NULL;
 }
 
 /* Base */
@@ -272,6 +321,112 @@ void BKE_view_layer_base_select(struct ViewLayer *view_layer, Base *selbase)
 	}
 }
 
+/****************************************************************************/
+/* Copying functions for datablocks that use ViewLayer/SceneCollection */
+
+/* Find the equivalent SceneCollection in the new tree */
+static SceneCollection *scene_collection_from_new_tree(SceneCollection *sc_reference, SceneCollection *sc_dst, SceneCollection *sc_src)
+{
+	if (sc_src == sc_reference) {
+		return sc_dst;
+	}
+
+	for (SceneCollection *nsc_src = sc_src->scene_collections.first, *nsc_dst = sc_dst->scene_collections.first;
+	     nsc_src;
+	     nsc_src = nsc_src->next, nsc_dst = nsc_dst->next)
+	{
+		SceneCollection *found = scene_collection_from_new_tree(sc_reference, nsc_dst, nsc_src);
+		if (found != NULL) {
+			return found;
+		}
+	}
+	return NULL;
+}
+
+static void layer_collections_sync_flags(ListBase *layer_collections_dst, const ListBase *layer_collections_src)
+{
+	LayerCollection *layer_collection_dst = (LayerCollection *)layer_collections_dst->first;
+	const LayerCollection *layer_collection_src = (const LayerCollection *)layer_collections_src->first;
+	while (layer_collection_dst != NULL) {
+		layer_collection_dst->flag = layer_collection_src->flag;
+
+		if (layer_collection_dst->properties != NULL) {
+			IDP_FreeProperty(layer_collection_dst->properties);
+			MEM_SAFE_FREE(layer_collection_dst->properties);
+		}
+
+		if (layer_collection_src->properties != NULL) {
+			layer_collection_dst->properties = IDP_CopyProperty(layer_collection_src->properties);
+		}
+
+		layer_collections_sync_flags(&layer_collection_dst->layer_collections,
+		                             &layer_collection_src->layer_collections);
+
+		layer_collection_dst = layer_collection_dst->next;
+		layer_collection_src = layer_collection_src->next;
+	}
+}
+
+/* recreate the LayerCollection tree */
+static void layer_collections_recreate(
+        ViewLayer *view_layer_dst, ListBase *lb_src, SceneCollection *mc_dst, SceneCollection *mc_src)
+{
+	for (LayerCollection *lc_src = lb_src->first; lc_src; lc_src = lc_src->next) {
+		SceneCollection *sc_dst = scene_collection_from_new_tree(lc_src->scene_collection, mc_dst, mc_src);
+		BLI_assert(sc_dst);
+
+		/* instead of synchronizing both trees we simply re-create it */
+		BKE_collection_link(view_layer_dst, sc_dst);
+	}
+}
+
+/**
+ * Only copy internal data of ViewLayer from source to already allocated/initialized destination.
+ *
+ * \param mc_src Master Collection the source ViewLayer links in.
+ * \param mc_dst Master Collection the destination ViewLayer links in.
+ * \param flag  Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
+ */
+void BKE_view_layer_copy_data(ViewLayer *view_layer_dst, ViewLayer *view_layer_src, SceneCollection* mc_dst, SceneCollection* mc_src,
+                               const int flag)
+{
+	IDPropertyTemplate val = {0};
+
+	if (view_layer_dst->id_properties != NULL) {
+		view_layer_dst->id_properties = IDP_CopyProperty_ex(view_layer_dst->id_properties, flag);
+	}
+	BKE_freestyle_config_copy(&view_layer_dst->freestyle_config, &view_layer_src->freestyle_config, flag);
+
+	view_layer_dst->stats = NULL;
+	view_layer_dst->properties_evaluated = NULL;
+	view_layer_dst->properties = IDP_New(IDP_GROUP, &val, ROOT_PROP);
+	IDP_MergeGroup_ex(view_layer_dst->properties, view_layer_src->properties, true, flag);
+
+	/* we start fresh with no overrides and no visibility flags set
+	 * instead of syncing both trees we simply unlink and relink the scene collection */
+	BLI_listbase_clear(&view_layer_dst->layer_collections);
+	BLI_listbase_clear(&view_layer_dst->object_bases);
+	BLI_listbase_clear(&view_layer_dst->drawdata);
+
+	layer_collections_recreate(view_layer_dst, &view_layer_src->layer_collections, mc_dst, mc_src);
+
+	/* Now we handle the syncing for visibility, selectability, ... */
+	layer_collections_sync_flags(&view_layer_dst->layer_collections, &view_layer_src->layer_collections);
+
+	Object *active_ob = OBACT(view_layer_src);
+	for (Base *base_src = view_layer_src->object_bases.first, *base_dst = view_layer_dst->object_bases.first;
+	     base_src;
+	     base_src = base_src->next, base_dst = base_dst->next)
+	{
+		base_dst->flag = base_src->flag;
+		base_dst->flag_legacy = base_src->flag_legacy;
+
+		if (base_dst->object == active_ob) {
+			view_layer_dst->basact = base_dst;
+		}
+	}
+}
+
 static void view_layer_object_base_unref(ViewLayer *view_layer, Base *base)
 {
 	base->refcount--;
@@ -416,7 +571,7 @@ LayerCollection *BKE_layer_collection_get_active_ensure(Scene *scene, ViewLayer
 	if (lc == NULL) {
 		BLI_assert(BLI_listbase_is_empty(&view_layer->layer_collections));
 		/* When there is no collection linked to this ViewLayer, create one. */
-		SceneCollection *sc = BKE_collection_add(scene, NULL, NULL);
+		SceneCollection *sc = BKE_collection_add(&scene->id, NULL, COLLECTION_TYPE_NONE, NULL);
 		lc = BKE_collection_link(view_layer, sc);
 		/* New collection has to be the active one. */
 		BLI_assert(lc == BKE_layer_collection_get_active(view_layer));
@@ -552,15 +707,15 @@ static void layer_collection_swap(
 }
 
 /**
- * Move \a lc_src into \a lc_dst. Both have to be stored in \a sl.
+ * Move \a lc_src into \a lc_dst. Both have to be stored in \a view_layer.
  * If \a lc_src is directly linked to the ViewLayer it's unlinked
  */
-bool BKE_layer_collection_move_into(const Scene *scene, LayerCollection *lc_dst, LayerCollection *lc_src)
+bool BKE_layer_collection_move_into(const ID *owner_id, LayerCollection *lc_dst, LayerCollection *lc_src)
 {
-	ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, lc_src);
+	ViewLayer *view_layer = BKE_view_layer_find_from_collection(owner_id, lc_src);
 	bool is_directly_linked = false;
 
-	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(scene, lc_dst))) {
+	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(owner_id, lc_dst))) {
 		return false;
 	}
 
@@ -596,7 +751,7 @@ bool BKE_layer_collection_move_into(const Scene *scene, LayerCollection *lc_dst,
 			layer_collection_swap(view_layer, &view_layer->layer_collections, NULL, lc_temp, lc_src);
 		}
 
-		if (!BKE_collection_move_into(scene, lc_dst->scene_collection, lc_src->scene_collection)) {
+		if (!BKE_collection_move_into(owner_id, lc_dst->scene_collection, lc_src->scene_collection)) {
 			if (!is_directly_linked) {
 				/* Swap back and remove */
 				layer_collection_swap(view_layer, NULL, NULL, lc_temp, lc_src);
@@ -622,13 +777,13 @@ bool BKE_layer_collection_move_into(const Scene *scene, LayerCollection *lc_dst,
  * Move \a lc_src above \a lc_dst. Both have to be stored in \a view_layer.
  * If \a lc_src is directly linked to the ViewLayer it's unlinked
  */
-bool BKE_layer_collection_move_above(const Scene *scene, LayerCollection *lc_dst, LayerCollection *lc_src)
+bool BKE_layer_collection_move_above(const ID *owner_id, LayerCollection *lc_dst, LayerCollection *lc_src)
 {
-	ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, lc_src);
+	ViewLayer *view_layer = BKE_view_layer_find_from_collection(owner_id, lc_src);
 	const bool is_directly_linked_src = BLI_findindex(&view_layer->layer_collections, lc_src) != -1;
 	const bool is_directly_linked_dst = BLI_findindex(&view_layer->layer_collections, lc_dst) != -1;
 
-	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(scene, lc_dst))) {
+	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(owner_id, lc_dst))) {
 		return false;
 	}
 
@@ -671,7 +826,7 @@ bool BKE_layer_collection_move_above(const Scene *scene, LayerCollection *lc_dst
 			layer_collection_swap(view_layer, &view_layer->layer_collections, NULL, lc_temp, lc_src);
 		}
 
-		if (!BKE_collection_move_above(scene, lc_dst->scene_collection, lc_src->scene_collection)) {
+		if (!BKE_collection_move_above(owner_id, lc_dst->scene_collection, lc_src->scene_collection)) {
 			if (!is_directly_linked_src) {
 				/* Swap back and remove */
 				layer_collection_swap(view_layer, NULL, NULL, lc_temp, lc_src);
@@ -694,16 +849,16 @@ bool BKE_layer_collection_move_above(const Scene *scene, LayerCollection *lc_dst
 }
 
 /**
- * Move \a lc_src below \a lc_dst. Both have to be stored in \a sl.
+ * Move \a lc_src below \a lc_dst. Both have to be stored in \a view_layer.
  * If \a lc_src is directly linked to the ViewLayer it's unlinked
  */
-bool BKE_layer_collection_move_below(const Scene *scene, LayerCollection *lc_dst, LayerCollection *lc_src)
+bool BKE_layer_collection_move_below(const ID *owner_id, LayerCollection *lc_dst, LayerCollection *lc_src)
 {
-	ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, lc_src);
+	ViewLayer *view_layer = BKE_view_layer_find_from_collection(owner_id, lc_src);
 	const bool is_directly_linked_src = BLI_findindex(&view_layer->layer_collections, lc_src) != -1;
 	const bool is_directly_linked_dst = BLI_findindex(&view_layer->layer_collections, lc_dst) != -1;
 
-	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(scene, lc_dst))) {
+	if ((!view_layer) || (view_layer != BKE_view_layer_find_from_collection(owner_id, lc_dst))) {
 		return false;
 	}
 
@@ -746,7 +901,7 @@ bool BKE_layer_collection_move_below(const Scene *scene, LayerCollection *lc_dst
 			layer_collection_swap(view_layer, &view_layer->layer_collections, NULL, lc_temp, lc_src);
 		}
 
-		if (!BKE_collection_move_below(scene, lc_dst->scene_collection, lc_src->scene_collection)) {
+		if (!BKE_collection_move_below(owner_id, lc_dst->scene_collection, lc_src->scene_collection)) {
 			if (!is_directly_linked_src) {
 				/* Swap back and remove */
 				layer_collection_swap(view_layer, NULL, NULL, lc_temp, lc_src);
@@ -809,9 +964,9 @@ static bool layer_collection_resync(ViewLayer *view_layer, LayerCollection *lc,
  * Update the scene layers so that any LayerCollection that points
  * to \a sc is re-synced again
  */
-void BKE_layer_collection_resync(const Scene *scene, const SceneCollection *sc)
+void BKE_layer_collection_resync(const ID *owner_id, const SceneCollection *sc)
 {
-	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+	for (ViewLayer *view_layer = BKE_view_layer_first_from_id(owner_id); view_layer; view_layer = view_layer->next) {
 		for (LayerCollection *lc = view_layer->layer_collections.first; lc; lc = lc->next) {
 			layer_collection_resync(view_layer, lc, sc);
 		}
@@ -1025,9 +1180,9 @@ static LayerCollection *find_layer_collection_by_scene_collection(LayerCollectio
 /**
  * Add a new LayerCollection for all the ViewLayers that have sc_parent
  */
-void BKE_layer_sync_new_scene_collection(Scene *scene, const SceneCollection *sc_parent, SceneCollection *sc)
+void BKE_layer_sync_new_scene_collection(ID *owner_id, const SceneCollection *sc_parent, SceneCollection *sc)
 {
-	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+	for (ViewLayer *view_layer = BKE_view_layer_first_from_id(owner_id); view_layer; view_layer = view_layer->next) {
 		for (LayerCollection *lc = view_layer->layer_collections.first; lc; lc = lc->next) {
 			LayerCollection *lc_parent = find_layer_collection_by_scene_collection(lc, sc_parent);
 			if (lc_parent) {
@@ -1040,9 +1195,9 @@ void BKE_layer_sync_new_scene_collection(Scene *scene, const SceneCollection *sc
 /**
  * Add a corresponding ObjectBase to all the equivalent LayerCollection
  */
-void BKE_layer_sync_object_link(const Scene *scene, SceneCollection *sc, Object *ob)
+void BKE_layer_sync_object_link(const ID *owner_id, SceneCollection *sc, Object *ob)
 {
-	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+	for (ViewLayer *view_layer = BKE_view_layer_first_from_id(owner_id); view_layer; view_layer = view_layer->next) {
 		for (LayerCollection *lc = view_layer->layer_collections.first; lc; lc = lc->next) {
 			LayerCollection *found = find_layer_collection_by_scene_collection(lc, sc);
 			if (found) {
@@ -1056,9 +1211,9 @@ void BKE_layer_sync_object_link(const Scene *scene, SceneCollection *sc, Object
  * Remove the equivalent object base to all layers that have this collection
  * also remove all reference to ob in the filter_objects
  */
-void BKE_layer_sync_object_unlink(const Scene *scene, SceneCollection *sc, Object *ob)
+void BKE_layer_sync_object_unlink(const ID *owner_id, SceneCollection *sc, Object *ob)
 {
-	for (ViewLayer *view_layer = scene->view_layers.first; view_layer; view_layer = view_layer->next) {
+	for (ViewLayer *view_layer = BKE_view_layer_first_from_id(owner_id); view_layer; view_layer = view_layer->next) {
 		for (LayerCollection *lc = view_layer->layer_collections.first; lc; lc = lc->next) {
 			LayerCollection *found = find_layer_collection_by_scene_collection(lc, sc);
 			if (found) {
@@ -1074,9 +1229,9 @@ void BKE_layer_sync_object_unlink(const Scene *scene, SceneCollection *sc, Objec
 /**
  * Add a new datablock override
  */
-void BKE_override_view_layer_datablock_add(ViewLayer *view_layer, int id_type, const char *data_path, const ID *id)
+void BKE_override_view_layer_datablock_add(ViewLayer *view_layer, int id_type, const char *data_path, const ID *owner_id)
 {
-	UNUSED_VARS(view_layer, id_type, data_path, id);
+	UNUSED_VARS(view_layer, id_type, data_path, owner_id);
 	TODO_LAYER_OVERRIDE;
 }
 
@@ -1934,32 +2089,43 @@ static void idproperty_reset(IDProperty **props, IDProperty *props_ref)
 }
 
 void BKE_layer_eval_layer_collection_pre(const struct EvaluationContext *UNUSED(eval_ctx),
-                                         Scene *scene, ViewLayer *view_layer)
+                                         ID *owner_id, ViewLayer *view_layer)
 {
-	DEBUG_PRINT("%s on scene:%s %s (%p)\n", __func__, scene->id.name, view_layer->name, view_layer);
+	DEBUG_PRINT("%s on %s (%p)\n", __func__, view_layer->name, view_layer);
+	Scene *scene = (GS(owner_id->name) == ID_SCE) ? (Scene *)owner_id : NULL;
+
 	for (Base *base = view_layer->object_bases.first; base != NULL; base = base->next) {
 		base->flag &= ~(BASE_VISIBLED | BASE_SELECTABLED);
-		idproperty_reset(&base->collection_properties, scene->collection_properties);
+		idproperty_reset(&base->collection_properties, scene ? scene->collection_properties : NULL);
 	}
 
 	/* Sync properties from scene to scene layer. */
-	idproperty_reset(&view_layer->properties_evaluated, scene->layer_properties);
+	idproperty_reset(&view_layer->properties_evaluated, scene ? scene->layer_properties : NULL);
 	IDP_MergeGroup(view_layer->properties_evaluated, view_layer->properties, true);
 
 	/* TODO(sergey): Is it always required? */
 	view_layer->flag |= VIEW_LAYER_ENGINE_DIRTY;
 }
 
+static const char *collection_type_lookup[] =
+{
+    "None", /* COLLECTION_TYPE_NONE */
+    "Group Internal", /* COLLECTION_TYPE_GROUP_INTERNAL */
+};
+
 void BKE_layer_eval_layer_collection(const struct EvaluationContext *UNUSED(eval_ctx),
                                      LayerCollection *layer_collection,
                                      LayerCollection *parent_layer_collection)
 {
-	DEBUG_PRINT("%s on %s (%p), parent %s (%p)\n",
+	DEBUG_PRINT("%s on %s (%p) [%s], parent %s (%p) [%s]\n",
 	            __func__,
 	            layer_collection->scene_collection->name,
 	            layer_collection->scene_collection,
+	            collection_type_lookup[layer_collection->scene_collection->type],
 	            (parent_layer_collection != NULL) ? parent_layer_collection->scene_collection->name : "NONE",
-	            (parent_layer_collection != NULL) ? parent_layer_collection->scene_collection : NULL);
+	            (parent_layer_collection != NULL) ? parent_layer_collection->scene_collection : NULL,
+	            (parent_layer_collection != NULL) ? collection_type_lookup[parent_layer_collection->scene_collection->type] : "");
+	BLI_assert(layer_collection != parent_layer_collection);
 
 	/* visibility */
 	layer_collection->flag_evaluated = layer_collection->flag;