Render Layers and Collections (merge from render-layers)

Design Documents
----------------

* https://wiki.blender.org/index.php/Dev:2.8/Source/Layers

* https://wiki.blender.org/index.php/Dev:2.8/Source/DataDesignRevised

User Commit Log
---------------

* New Layer and Collection system to replace render layers and viewport layers.

* A layer is a set of collections of objects (and their drawing options) required for specific tasks.

* A collection is a set of objects, equivalent of the old layers in Blender. A collection can be shared across multiple layers.

* All Scenes have a master collection that all other collections are children of.

* New collection "context" tab (in Properties Editor)

* New temporary viewport "collections" panel to control per-collection
visibility

Missing User Features
---------------------

* Collection "Filter"
  Option to add objects based on their names

* Collection Manager operators
  The existing buttons  are placeholders

* Collection Manager drawing
  The editor main region is empty

* Collection Override

* Per-Collection engine settings
  This will come as a separate commit, as part of the clay-engine branch

Dev Commit Log
--------------

* New DNA file (DNA_layer_types.h) with the new structs
  We are replacing Base by a new extended Base while keeping it backward
  compatible with some legacy settings (i.e., lay, flag_legacy).

  Renamed all Base to BaseLegacy to make it clear the areas of code that
  still need to be converted

  Note: manual changes were required on - deg_builder_nodes.h, rna_object.c, KX_Light.cpp

* Unittesting for main syncronization requirements
  - read, write, add/copy/remove objects, copy scene, collection
  link/unlinking, context)

* New Editor: Collection Manager
  Based on patch by Julian Eisel
  This is extracted from the layer-manager branch. With the following changes:

    - Renamed references of layer manager to collections manager

    - I doesn't include the editors/space_collections/ draw and util files

    - The drawing code itself will be implemented separately by Julian

* Base / Object:
  A little note about them. Original Blender code would try to keep them
  in sync through the code, juggling flags back and forth. This will now
  be handled by Depsgraph, keeping Object and Bases more separated
  throughout the non-rendering code.

  Scene.base is being cleared in doversion, and the old viewport drawing
  code was poorly converted to use the new bases while the new viewport
  code doesn't get merged and replace the old one.

Python API Changes
------------------

```
- scene.layers
+ # no longer exists

- scene.objects
+ scene.scene_layers.active.objects

- scene.objects.active
+ scene.render_layers.active.objects.active

- bpy.context.scene.objects.link()
+ bpy.context.scene_collection.objects.link()

- bpy_extras.object_utils.object_data_add(context, obdata, operator=None, use_active_layer=True, name=None)
+ bpy_extras.object_utils.object_data_add(context, obdata, operator=None, name=None)

- bpy.context.object.select
+ bpy.context.object.select = True
+ bpy.context.object.select = False
+ bpy.context.object.select_get()
+ bpy.context.object.select_set(action='SELECT')
+ bpy.context.object.select_set(action='DESELECT')

-AddObjectHelper.layers
+ # no longer exists
```

5 files changed, 350 insertions, 25 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 060d290df32..e669bf3b4a6 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -72,6 +72,7 @@
 #include "DNA_ipo_types.h"
 #include "DNA_key_types.h"
 #include "DNA_lattice_types.h"
+#include "DNA_layer_types.h"
 #include "DNA_lamp_types.h"
 #include "DNA_linestyle_types.h"
 #include "DNA_meta_types.h"
@@ -102,6 +103,8 @@
 #include "DNA_movieclip_types.h"
 #include "DNA_mask_types.h"
 
+#include "RNA_access.h"
+
 #include "MEM_guardedalloc.h"
 
 #include "BLI_endian_switch.h"
@@ -5630,11 +5633,29 @@ static bool scene_validate_setscene__liblink(Scene *sce, const int totscene)
 }
 #endif
 
+static void lib_link_scene_collection(FileData *fd, Library *lib, SceneCollection *sc)
+{
+	for (LinkData *link = sc->objects.first; link; link = link->next) {
+		link->data = newlibadr_us(fd, lib, link->data);
+		BLI_assert(link->data);
+	}
+
+	for (LinkData *link = sc->filter_objects.first; link; link = link->next) {
+		link->data = newlibadr_us(fd, lib, link->data);
+		BLI_assert(link->data);
+	}
+
+	for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
+		lib_link_scene_collection(fd, lib, nsc);
+	}
+}
+
 static void lib_link_scene(FileData *fd, Main *main)
 {
 	Scene *sce;
-	Base *base, *next;
+	BaseLegacy *base_legacy, *base_legacy_next;
 	Sequence *seq;
+	SceneLayer *sl;
 	SceneRenderLayer *srl;
 	FreestyleModuleConfig *fmc;
 	FreestyleLineSet *fls;
@@ -5684,17 +5705,17 @@ static void lib_link_scene(FileData *fd, Main *main)
 			
 			sce->toolsettings->particle.shape_object = newlibadr(fd, sce->id.lib, sce->toolsettings->particle.shape_object);
 			
-			for (base = sce->base.first; base; base = next) {
-				next = base->next;
+			for (base_legacy = sce->base.first; base_legacy; base_legacy = base_legacy_next) {
+				base_legacy_next = base_legacy->next;
 				
-				base->object = newlibadr_us(fd, sce->id.lib, base->object);
+				base_legacy->object = newlibadr_us(fd, sce->id.lib, base_legacy->object);
 				
-				if (base->object == NULL) {
+				if (base_legacy->object == NULL) {
 					blo_reportf_wrap(fd->reports, RPT_WARNING, TIP_("LIB: object lost from scene: '%s'"),
 					                 sce->id.name + 2);
-					BLI_remlink(&sce->base, base);
-					if (base == sce->basact) sce->basact = NULL;
-					MEM_freeN(base);
+					BLI_remlink(&sce->base, base_legacy);
+					if (base_legacy == sce->basact) sce->basact = NULL;
+					MEM_freeN(base_legacy);
 				}
 			}
 			
@@ -5780,6 +5801,15 @@ static void lib_link_scene(FileData *fd, Main *main)
 			/* Motion Tracking */
 			sce->clip = newlibadr_us(fd, sce->id.lib, sce->clip);
 
+			lib_link_scene_collection(fd, sce->id.lib, sce->collection);
+
+			for (sl = sce->render_layers.first; sl; sl = sl->next) {
+				for (Base *base = sl->object_bases.first; base; base = base->next) {
+					/* we only bump the use count for the collection objects */
+					base->object = newlibadr(fd, sce->id.lib, base->object);
+				}
+			}
+
 #ifdef USE_SETSCENE_CHECK
 			if (sce->set != NULL) {
 				/* link flag for scenes with set would be reset later,
@@ -5883,12 +5913,42 @@ static void direct_link_view_settings(FileData *fd, ColorManagedViewSettings *vi
 		direct_link_curvemapping(fd, view_settings->curve_mapping);
 }
 
+static void direct_link_scene_collection(FileData *fd, SceneCollection *sc)
+{
+	link_list(fd, &sc->objects);
+	link_list(fd, &sc->filter_objects);
+	link_list(fd, &sc->scene_collections);
+
+	for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
+		direct_link_scene_collection(fd, nsc);
+	}
+}
+
+static void direct_link_layer_collections(FileData *fd, ListBase *lb)
+{
+	link_list(fd, lb);
+	for (LayerCollection *lc = lb->first; lc; lc = lc->next) {
+		lc->scene_collection = newdataadr(fd, lc->scene_collection);
+
+		link_list(fd, &lc->object_bases);
+
+		for (LinkData *link = lc->object_bases.first; link; link = link->next) {
+			link->data = newdataadr(fd, link->data);
+		}
+
+		link_list(fd, &lc->overrides);
+
+		direct_link_layer_collections(fd, &lc->layer_collections);
+	}
+}
+
 static void direct_link_scene(FileData *fd, Scene *sce)
 {
 	Editing *ed;
 	Sequence *seq;
 	MetaStack *ms;
 	RigidBodyWorld *rbw;
+	SceneLayer *sl;
 	SceneRenderLayer *srl;
 	
 	sce->theDag = NULL;
@@ -6139,6 +6199,19 @@ static void direct_link_scene(FileData *fd, Scene *sce)
 	sce->preview = direct_link_preview_image(fd, sce->preview);
 
 	direct_link_curvemapping(fd, &sce->r.mblur_shutter_curve);
+
+	/* this runs before the very first doversion */
+	if (sce->collection) {
+		sce->collection = newdataadr(fd, sce->collection);
+		direct_link_scene_collection(fd, sce->collection);
+	}
+
+	link_list(fd, &sce->render_layers);
+	for (sl = sce->render_layers.first; sl; sl = sl->next) {
+		link_list(fd, &sl->object_bases);
+		sl->basact = newdataadr(fd, sl->basact);
+		direct_link_layer_collections(fd, &sl->layer_collections);
+	}
 }
 
 /* ************ READ WM ***************** */
@@ -6482,6 +6555,10 @@ static void lib_link_screen(FileData *fd, Main *main)
 						
 						slogic->gpd = newlibadr_us(fd, sc->id.lib, slogic->gpd);
 					}
+					else if (sl->spacetype == SPACE_COLLECTIONS) {
+						SpaceCollections *slayer = (SpaceCollections *)sl;
+						slayer->flag |= SC_COLLECTION_DATA_REFRESH;
+					}
 				}
 			}
 			sc->id.tag &= ~LIB_TAG_NEED_LINK;
@@ -6867,6 +6944,10 @@ void blo_lib_link_screen_restore(Main *newmain, bScreen *curscreen, Scene *cursc
 					
 					slogic->gpd = restore_pointer_by_name(id_map, (ID *)slogic->gpd, USER_REAL);
 				}
+				else if (sl->spacetype == SPACE_COLLECTIONS) {
+					SpaceCollections *slayer = (SpaceCollections *)sl;
+					slayer->flag |= SC_COLLECTION_DATA_REFRESH;
+				}
 			}
 		}
 	}
@@ -7261,6 +7342,10 @@ static bool direct_link_screen(FileData *fd, bScreen *sc)
 				sclip->scopes.track_preview = NULL;
 				sclip->scopes.ok = 0;
 			}
+			else if (sl->spacetype == SPACE_COLLECTIONS) {
+				SpaceCollections *slayer = (SpaceCollections *)sl;
+				slayer->flag |= SC_COLLECTION_DATA_REFRESH;
+			}
 		}
 		
 		BLI_listbase_clear(&sa->actionzones);
@@ -7457,7 +7542,7 @@ static void lib_link_group(FileData *fd, Main *main)
 			if (add_us) {
 				id_us_ensure_real(&group->id);
 			}
-			BKE_group_object_unlink(group, NULL, NULL, NULL);	/* removes NULL entries */
+			BKE_group_object_unlink(group, NULL);	/* removes NULL entries */
 		}
 	}
 }
@@ -8389,6 +8474,7 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 	blo_do_versions_250(fd, lib, main);
 	blo_do_versions_260(fd, lib, main);
 	blo_do_versions_270(fd, lib, main);
+	blo_do_versions_280(fd, lib, main);
 
 	/* WATCH IT!!!: pointers from libdata have not been converted yet here! */
 	/* WATCH IT 2!: Userdef struct init see do_versions_userdef() above! */
@@ -8400,8 +8486,8 @@ static void do_versions_after_linking(Main *main)
 {
 //	printf("%s for %s (%s), %d.%d\n", __func__, main->curlib ? main->curlib->name : main->name,
 //	       main->curlib ? "LIB" : "MAIN", main->versionfile, main->subversionfile);
-
 	do_versions_after_linking_270(main);
+	do_versions_after_linking_280(main);
 }
 
 static void lib_link_all(FileData *fd, Main *main)
@@ -9484,9 +9570,24 @@ static void expand_object(FileData *fd, Main *mainvar, Object *ob)
 	}
 }
 
+static void expand_scene_collection(FileData *fd, Main *mainvar, SceneCollection *sc)
+{
+	for (LinkData *link = sc->objects.first; link; link = link->next) {
+		expand_doit(fd, mainvar, link->data);
+	}
+
+	for (LinkData *link = sc->filter_objects.first; link; link = link->next) {
+		expand_doit(fd, mainvar, link->data);
+	}
+
+	for (SceneCollection *nsc= sc->scene_collections.first; nsc; nsc = nsc->next) {
+		expand_scene_collection(fd, mainvar, nsc);
+	}
+}
+
 static void expand_scene(FileData *fd, Main *mainvar, Scene *sce)
 {
-	Base *base;
+	BaseLegacy *base;
 	SceneRenderLayer *srl;
 	FreestyleModuleConfig *module;
 	FreestyleLineSet *lineset;
@@ -9553,6 +9654,8 @@ static void expand_scene(FileData *fd, Main *mainvar, Scene *sce)
 	}
 
 	expand_doit(fd, mainvar, sce->clip);
+
+	expand_scene_collection(fd, mainvar, sce->collection);
 }
 
 static void expand_camera(FileData *fd, Main *mainvar, Camera *ca)
@@ -9799,7 +9902,7 @@ static bool object_in_any_scene(Main *mainvar, Object *ob)
 static void give_base_to_objects(Main *mainvar, Scene *scene, View3D *v3d, Library *lib, const short flag)
 {
 	Object *ob;
-	Base *base;
+	BaseLegacy *base;
 	const unsigned int active_lay = (flag & FILE_ACTIVELAY) ? BKE_screen_view3d_layer_active(v3d, scene) : 0;
 	const bool is_link = (flag & FILE_LINK) != 0;
 
@@ -9820,7 +9923,7 @@ static void give_base_to_objects(Main *mainvar, Scene *scene, View3D *v3d, Libra
 			}
 
 			if (do_it) {
-				base = MEM_callocN(sizeof(Base), __func__);
+				base = MEM_callocN(sizeof(BaseLegacy), __func__);
 				BLI_addtail(&scene->base, base);
 
 				if (active_lay) {
@@ -9835,7 +9938,7 @@ static void give_base_to_objects(Main *mainvar, Scene *scene, View3D *v3d, Libra
 
 				base->object = ob;
 				base->lay = ob->lay;
-				base->flag = ob->flag;
+				BKE_scene_base_flag_sync_from_object(base);
 
 				CLAMP_MIN(ob->id.us, 0);
 				id_us_plus_no_lib((ID *)ob);
@@ -9851,7 +9954,7 @@ static void give_base_to_groups(
         Main *mainvar, Scene *scene, View3D *v3d, Library *UNUSED(lib), const short UNUSED(flag))
 {
 	Group *group;
-	Base *base;
+	BaseLegacy *base;
 	Object *ob;
 	const unsigned int active_lay = BKE_screen_view3d_layer_active(v3d, scene);
 
@@ -9868,8 +9971,8 @@ static void give_base_to_groups(
 
 			/* assign the base */
 			base = BKE_scene_base_add(scene, ob);
-			base->flag |= SELECT;
-			base->object->flag = base->flag;
+			base->flag_legacy |= SELECT;
+			BKE_scene_base_flag_sync_from_base(base);
 			DAG_id_tag_update(&ob->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
 			scene->basact = base;
 
@@ -9951,10 +10054,10 @@ static ID *link_named_part(
 static void link_object_postprocess(ID *id, Scene *scene, View3D *v3d, const short flag)
 {
 	if (scene) {
-		Base *base;
+		BaseLegacy *base;
 		Object *ob;
 
-		base = MEM_callocN(sizeof(Base), "app_nam_part");
+		base = MEM_callocN(sizeof(BaseLegacy), "app_nam_part");
 		BLI_addtail(&scene->base, base);
 
 		ob = (Object *)id;
@@ -9967,12 +10070,12 @@ static void link_object_postprocess(ID *id, Scene *scene, View3D *v3d, const sho
 		ob->mode = OB_MODE_OBJECT;
 		base->lay = ob->lay;
 		base->object = ob;
-		base->flag = ob->flag;
+		base->flag_legacy = ob->flag;
 		id_us_plus_no_lib((ID *)ob);
 
 		if (flag & FILE_AUTOSELECT) {
-			base->flag |= SELECT;
-			base->object->flag = base->flag;
+			base->flag_legacy |= SELECT;
+			BKE_scene_base_flag_sync_from_base(base);
 			/* do NOT make base active here! screws up GUI stuff, if you want it do it on src/ level */
 		}
 	}
diff --git a/source/blender/blenloader/intern/readfile.h b/source/blender/blenloader/intern/readfile.h
index d97bef13a78..50cdeca16b5 100644
--- a/source/blender/blenloader/intern/readfile.h
+++ b/source/blender/blenloader/intern/readfile.h
@@ -34,6 +34,8 @@
 #define __READFILE_H__
 
 #include "zlib.h"
+#include "DNA_sdna_types.h"
+#include "DNA_space_types.h"
 #include "DNA_windowmanager_types.h"  /* for ReportType */
 
 struct OldNewMap;
@@ -169,8 +171,10 @@ void blo_do_versions_pre250(struct FileData *fd, struct Library *lib, struct Mai
 void blo_do_versions_250(struct FileData *fd, struct Library *lib, struct Main *main);
 void blo_do_versions_260(struct FileData *fd, struct Library *lib, struct Main *main);
 void blo_do_versions_270(struct FileData *fd, struct Library *lib, struct Main *main);
+void blo_do_versions_280(struct FileData *fd, struct Library *lib, struct Main *main);
 
 void do_versions_after_linking_270(struct Main *main);
+void do_versions_after_linking_280(struct Main *main);
 
 #endif
 
diff --git a/source/blender/blenloader/intern/versioning_250.c b/source/blender/blenloader/intern/versioning_250.c
index 1956a17d57b..943e5479d9a 100644
--- a/source/blender/blenloader/intern/versioning_250.c
+++ b/source/blender/blenloader/intern/versioning_250.c
@@ -736,7 +736,7 @@ void blo_do_versions_250(FileData *fd, Library *lib, Main *main)
 	if (main->versionfile < 250) {
 		bScreen *screen;
 		Scene *scene;
-		Base *base;
+		BaseLegacy *base;
 		Material *ma;
 		Camera *cam;
 		Mesh *me;
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
new file mode 100644
index 00000000000..a4e69c9d514
--- /dev/null
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -0,0 +1,181 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s): Dalai Felinto
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ *
+ */
+
+/** \file blender/blenloader/intern/versioning_280.c
+ *  \ingroup blenloader
+ */
+
+/* allow readfile to use deprecated functionality */
+#define DNA_DEPRECATED_ALLOW
+
+#include "DNA_object_types.h"
+#include "DNA_layer_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_genfile.h"
+
+#include "BKE_collection.h"
+#include "BKE_layer.h"
+#include "BKE_main.h"
+#include "BKE_scene.h"
+
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+
+#include "BLO_readfile.h"
+#include "readfile.h"
+
+#include "MEM_guardedalloc.h"
+
+void do_versions_after_linking_280(Main *main)
+{
+	if (!MAIN_VERSION_ATLEAST(main, 280, 0)) {
+		for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+			/* since we don't have access to FileData we check the (always valid) first render layer instead */
+			if (scene->render_layers.first == NULL) {
+				SceneCollection *sc_master = BKE_collection_master(scene);
+				BLI_strncpy(sc_master->name, "Master Collection", sizeof(sc_master->name));
+
+				SceneCollection *collections[20] = {NULL};
+				bool is_visible[20];
+
+				int lay_used = 0;
+				for (int i = 0; i < 20; i++) {
+					char name[MAX_NAME];
+
+					BLI_snprintf(name, sizeof(collections[i]->name), "%d", i + 1);
+					collections[i] = BKE_collection_add(scene, sc_master, name);
+
+					is_visible[i] = (scene->lay & (1 << i));
+				}
+
+				for (BaseLegacy *base = scene->base.first; base; base = base->next) {
+					lay_used |= base->lay & ((1 << 20) - 1); /* ignore localview */
+
+					for (int i = 0; i < 20; i++) {
+						if ((base->lay & (1 << i)) != 0) {
+							BKE_collection_object_add(scene, collections[i], base->object);
+						}
+					}
+				}
+
+				scene->active_layer = 0;
+
+				if (!BKE_scene_uses_blender_game(scene)) {
+					for (SceneRenderLayer *srl = scene->r.layers.first; srl; srl = srl->next) {
+
+						SceneLayer *sl = BKE_scene_layer_add(scene, srl->name);
+						BKE_scene_layer_engine_set(sl, scene->r.engine);
+
+						if (srl->mat_override) {
+							BKE_collection_override_datablock_add((LayerCollection *)sl->layer_collections.first, "material", (ID *)srl->mat_override);
+						}
+
+						if (srl->light_override && BKE_scene_uses_blender_internal(scene)) {
+							/* not sure how we handle this, pending until we design the override system */
+							TODO_LAYER_OVERRIDE;
+						}
+
+						if (srl->lay != scene->lay) {
+							/* unlink master collection  */
+							BKE_collection_unlink(sl, sl->layer_collections.first);
+
+							/* add new collection bases */
+							for (int i = 0; i < 20; i++) {
+								if ((srl->lay & (1 << i)) != 0) {
+									BKE_collection_link(sl, collections[i]);
+								}
+							}
+						}
+
+						/* TODO: passes, samples, mask_layesr, exclude, ... */
+					}
+
+					if (BLI_findlink(&scene->render_layers, scene->r.actlay)) {
+						scene->active_layer = scene->r.actlay;
+					}
+				}
+
+				SceneLayer *sl = BKE_scene_layer_add(scene, "Render Layer");
+
+				/* In this particular case we can safely assume the data struct */
+				LayerCollection *lc = ((LayerCollection *)sl->layer_collections.first)->layer_collections.first;
+				for (int i = 0; i < 20; i++) {
+					if (!is_visible[i]) {
+						lc->flag &= ~COLLECTION_VISIBLE;
+					}
+					lc = lc->next;
+				}
+
+				/* but we still need to make the flags synced */
+				BKE_scene_layer_base_flag_recalculate(sl);
+
+				/* convert active base */
+				if (scene->basact) {
+					sl->basact = BKE_scene_layer_base_find(sl, scene->basact->object);
+				}
+
+				/* convert selected bases */
+				for (BaseLegacy *base = scene->base.first; base; base = base->next) {
+					Base *ob_base = BKE_scene_layer_base_find(sl, base->object);
+					if ((base->flag_legacy & SELECT) != 0) {
+						if ((ob_base->flag & BASE_SELECTABLED) != 0) {
+							ob_base->flag |= BASE_SELECTED;
+						}
+					}
+					else {
+						ob_base->flag &= ~BASE_SELECTED;
+					}
+				}
+
+				/* TODO: copy scene render data to layer */
+
+				/* Cleanup */
+				for (int i = 0; i < 20; i++) {
+					if ((lay_used & (1 << i)) == 0) {
+						BKE_collection_remove(scene, collections[i]);
+					}
+				}
+
+				/* remove bases once and for all */
+				for (BaseLegacy *base = scene->base.first; base; base = base->next) {
+					id_us_min(&base->object->id);
+				}
+				BLI_freelistN(&scene->base);
+				scene->basact = NULL;
+			}
+		}
+	}
+}
+
+void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *main)
+{
+	if (!MAIN_VERSION_ATLEAST(main, 280, 0)) {
+		if (!DNA_struct_elem_find(fd->filesdna, "Scene", "ListBase", "render_layers")) {
+			for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+				/* Master Collection */
+				scene->collection = MEM_callocN(sizeof(SceneCollection), "Master Collection");
+				BLI_strncpy(scene->collection->name, "Master Collection", sizeof(scene->collection->name));
+			}
+		}
+	}
+}
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index 5011f9836b7..4ddf83d306b 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -120,6 +120,7 @@
 #include "DNA_key_types.h"
 #include "DNA_lattice_types.h"
 #include "DNA_lamp_types.h"
+#include "DNA_layer_types.h"
 #include "DNA_linestyle_types.h"
 #include "DNA_meta_types.h"
 #include "DNA_mesh_types.h"
@@ -2626,10 +2627,34 @@ static void write_paint(WriteData *wd, Paint *p)
 	}
 }
 
+static void write_scene_collection(WriteData *wd, SceneCollection *sc)
+{
+	writestruct(wd, DATA, SceneCollection, 1, sc);
+
+	writelist(wd, DATA, LinkData, &sc->objects);
+	writelist(wd, DATA, LinkData, &sc->filter_objects);
+
+	for (SceneCollection *nsc = sc->scene_collections.first; nsc; nsc = nsc->next) {
+		write_scene_collection(wd, nsc);
+	}
+}
+
+static void write_layer_collections(WriteData *wd, ListBase *lb)
+{
+	for (LayerCollection *lc = lb->first; lc; lc = lc->next) {
+		writestruct(wd, DATA, LayerCollection, 1, lc);
+
+		writelist(wd, DATA, LinkData, &lc->object_bases);
+		writelist(wd, DATA, CollectionOverride, &lc->overrides);
+
+		write_layer_collections(wd, &lc->layer_collections);
+	}
+}
+
 static void write_scenes(WriteData *wd, ListBase *scebase)
 {
 	Scene *sce;
-	Base *base;
+	BaseLegacy *base;
 	Editing *ed;
 	Sequence *seq;
 	MetaStack *ms;
@@ -2641,6 +2666,7 @@ static void write_scenes(WriteData *wd, ListBase *scebase)
 	ToolSettings *tos;
 	FreestyleModuleConfig *fmc;
 	FreestyleLineSet *fls;
+	SceneLayer *sl;
 
 	sce = scebase->first;
 	while (sce) {
@@ -2656,7 +2682,7 @@ static void write_scenes(WriteData *wd, ListBase *scebase)
 		/* direct data */
 		base = sce->base.first;
 		while (base) {
-			writestruct(wd, DATA, Base, 1, base);
+			writestruct(wd, DATA, BaseLegacy, 1, base);
 			base = base->next;
 		}
 
@@ -2846,6 +2872,14 @@ static void write_scenes(WriteData *wd, ListBase *scebase)
 		write_previews(wd, sce->preview);
 		write_curvemapping_curves(wd, &sce->r.mblur_shutter_curve);
 
+		write_scene_collection(wd, sce->collection);
+
+		for (sl = sce->render_layers.first; sl; sl = sl->next) {
+			writestruct(wd, DATA, SceneLayer, 1, sl);
+			writelist(wd, DATA, Base, &sl->object_bases);
+			write_layer_collections(wd, &sl->layer_collections);
+		}
+
 		sce = sce->id.next;
 	}
 
@@ -3167,6 +3201,9 @@ static void write_screens(WriteData *wd, ListBase *scrbase)
 				else if (sl->spacetype == SPACE_INFO) {
 					writestruct(wd, DATA, SpaceInfo, 1, sl);
 				}
+				else if (sl->spacetype == SPACE_COLLECTIONS) {
+					writestruct(wd, DATA, SpaceCollections, 1, sl);
+				}
 
 				sl = sl->next;
 			}