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
```

1 files changed, 189 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_layer.h b/source/blender/blenkernel/BKE_layer.h
new file mode 100644
index 00000000000..850c63f535f
--- /dev/null
+++ b/source/blender/blenkernel/BKE_layer.h
@@ -0,0 +1,189 @@
+/*
+ * ***** 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 *****
+ */
+
+#ifndef __BKE_LAYER_H__
+#define __BKE_LAYER_H__
+
+/** \file blender/blenkernel/BKE_layer.h
+ *  \ingroup bke
+ */
+
+#include "BKE_collection.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define TODO_LAYER_SYNC /* syncing of SceneCollection and LayerCollection trees*/
+#define TODO_LAYER_SYNC_FILTER /* syncing of filter_objects across all trees */
+#define TODO_LAYER_OVERRIDE /* CollectionOverride */
+#define TODO_LAYER_CONTEXT /* get/set current (context) SceneLayer */
+#define TODO_LAYER_BASE /* BaseLegacy to Base related TODO */
+#define TODO_LAYER_OPERATORS /* collection mamanger and property panel operators */
+#define TODO_LAYER /* generic todo */
+
+struct Base;
+struct ID;
+struct LayerCollection;
+struct Main;
+struct Object;
+struct Scene;
+struct SceneCollection;
+struct SceneLayer;
+
+struct SceneLayer *BKE_scene_layer_add(struct Scene *scene, const char *name);
+
+bool BKE_scene_layer_remove(struct Main *bmain, struct Scene *scene, struct SceneLayer *sl);
+
+void BKE_scene_layer_free(struct SceneLayer *sl);
+
+void BKE_scene_layer_engine_set(struct SceneLayer *sl, const char *engine);
+
+void BKE_scene_layer_selected_objects_tag(struct SceneLayer *sl, const int tag);
+
+struct SceneLayer *BKE_scene_layer_find_from_collection(struct Scene *scene, struct LayerCollection *lc);
+struct Base *BKE_scene_layer_base_find(struct SceneLayer *sl, struct Object *ob);
+void BKE_scene_layer_base_deselect_all(struct SceneLayer *sl);
+void BKE_scene_layer_base_select(struct SceneLayer *sl, struct Base *selbase);
+void BKE_scene_layer_base_flag_recalculate(struct SceneLayer *sl);
+
+void BKE_layer_collection_free(struct SceneLayer *sl, struct LayerCollection *lc);
+
+struct LayerCollection *BKE_layer_collection_active(struct SceneLayer *sl);
+
+int BKE_layer_collection_count(struct SceneLayer *sl);
+
+int BKE_layer_collection_findindex(struct SceneLayer *sl, struct LayerCollection *lc);
+
+struct LayerCollection *BKE_collection_link(struct SceneLayer *sl, struct SceneCollection *sc);
+
+void BKE_collection_unlink(struct SceneLayer *sl, struct LayerCollection *lc);
+
+bool BKE_scene_layer_has_collection(struct SceneLayer *sl, struct SceneCollection *sc);
+bool BKE_scene_has_object(struct Scene *scene, struct Object *ob);
+
+/* syncing */
+
+void BKE_layer_sync_new_scene_collection(struct Scene *scene, const struct SceneCollection *sc_parent, struct SceneCollection *sc);
+void BKE_layer_sync_object_link(struct Scene *scene, struct SceneCollection *sc, struct Object *ob);
+void BKE_layer_sync_object_unlink(struct Scene *scene, struct SceneCollection *sc, struct Object *ob);
+
+/* override */
+
+void BKE_collection_override_datablock_add(struct LayerCollection *lc, const char *data_path, struct ID *id);
+
+/* iterators */
+
+void BKE_selected_objects_Iterator_begin(Iterator *iter, void *data_in);
+void BKE_selected_objects_Iterator_next(Iterator *iter);
+void BKE_selected_objects_Iterator_end(Iterator *iter);
+
+void BKE_visible_objects_Iterator_begin(Iterator *iter, void *data_in);
+void BKE_visible_objects_Iterator_next(Iterator *iter);
+void BKE_visible_objects_Iterator_end(Iterator *iter);
+
+void BKE_visible_bases_Iterator_begin(Iterator *iter, void *data_in);
+void BKE_visible_bases_Iterator_next(Iterator *iter);
+void BKE_visible_bases_Iterator_end(Iterator *iter);
+
+#define FOREACH_SELECTED_OBJECT(sl, _ob)                                      \
+	ITER_BEGIN(BKE_selected_objects_Iterator_begin,                           \
+	           BKE_selected_objects_Iterator_next,                            \
+	           BKE_selected_objects_Iterator_end,                             \
+	           sl, _ob)
+
+#define FOREACH_SELECTED_OBJECT_END                                           \
+	ITER_END
+
+#define FOREACH_VISIBLE_OBJECT(sl, _ob)                                       \
+	ITER_BEGIN(BKE_visible_objects_Iterator_begin,                            \
+	           BKE_visible_objects_Iterator_next,                             \
+	           BKE_visible_objects_Iterator_end,                              \
+	           sl, _ob)
+
+#define FOREACH_VISIBLE_OBJECT_END                                            \
+	ITER_END
+
+
+#define FOREACH_VISIBLE_BASE(sl, _object_base)                                \
+	ITER_BEGIN(BKE_visible_bases_Iterator_begin,                              \
+	           BKE_visible_bases_Iterator_next,                               \
+	           BKE_visible_bases_Iterator_end,                                \
+	           sl, _object_base)
+
+#define FOREACH_VISIBLE_BASE_END                                              \
+	ITER_END
+
+
+#define FOREACH_OBJECT(sl, _ob)                                               \
+{                                                                             \
+	Base *base;                                                               \
+	for (base = sl->object_bases.first; base; base = base->next) {            \
+	    _ob = base->object;
+
+#define FOREACH_OBJECT_END                                                    \
+    }                                                                         \
+}
+
+#define FOREACH_OBJECT_FLAG(scene, sl, flag, _ob)                             \
+{                                                                             \
+	IteratorBeginCb func_begin;                                               \
+	IteratorCb func_next, func_end;                                           \
+	void *data_in;                                                            \
+	                                                                          \
+	if (flag == SELECT) {                                                     \
+	    func_begin = &BKE_selected_objects_Iterator_begin;                    \
+	    func_next = &BKE_selected_objects_Iterator_next;                      \
+	    func_end = &BKE_selected_objects_Iterator_end;                        \
+	    data_in = sl;                                                         \
+    }                                                                         \
+	else {                                                                    \
+	    func_begin = BKE_scene_objects_Iterator_begin;                        \
+	    func_next = BKE_scene_objects_Iterator_next;                          \
+	    func_end = BKE_scene_objects_Iterator_end;                            \
+	    data_in = scene;                                                      \
+    }                                                                         \
+	ITER_BEGIN(func_begin, func_next, func_end, data_in, _ob)
+
+
+#define FOREACH_OBJECT_FLAG_END                                               \
+	ITER_END                                                                  \
+}
+
+/* temporary hacky solution waiting for final depsgraph evaluation */
+#define DEG_OBJECT_ITER(sl_, ob_)                                             \
+{                                                                             \
+	/* flush all the data to objects*/                                        \
+	Base *base_;                                                              \
+	for (base_ = sl->object_bases.first; base_; base_ = base_->next) {        \
+	    ob_ = base_->object;			                                      \
+	    ob_->base_flag = base_->flag;
+
+#define DEG_OBJECT_ITER_END                                                   \
+    }                                                                         \
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __BKE_LAYER_H__ */