This adds initial support for reordering collections from the Outliner
using drag & drop.
Although drag & drop support is limited to collections for now, this
lays most foundations for general drag & drop reordering support in the
Outliner. There are some design questions to be answered though:
* Would reordering of other data types (like objects) be a purely visual change or would it affect the order in which they are stored? (Would that make a difference for the user?)
* Should/can we allow mixing of different data types? (e.g. mixing render layers with objects)
* How could we realize this technically?
Notes:
* "Sort Alphabetically" has to be disabled to use this ("View" menu).
* Reordering only works with collections on the same hierarchy level.
* Added some visual feedback that should work quite well, it's by far not a final design though: {F493806}
* Modified collection orders are stored in .blends.
* Reordering can be undone.
* Did minor cleanups here and there.
Every time:
* A collection settings is set
* A collection visibility changes
* An object is added/removed/ ...
We need to recalculate the "accumulated" CollectionEngineSettings that
the render engine should use for an object.
This is to be handled by the depsgraph. Meanwhile this code should allow
us to start using those settings in the render engines.
Note: We are storing this in the objects, which means we can only have
one active calculated option every time.
This is intended to get the conversation with the Depsgraph department
going.
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
```
