The motivation is to keep backward compatibility after deprecating
`material.use_nodes()` and `world.use_nodes`. For example the
following script would behave the same way in 4.5 and 5.0:
```python
mat = bpy.data.materials.new("My new mat")
mat.use_nodes = True
```
Pull Request: https://projects.blender.org/blender/blender/pulls/147052
"Use Nodes" was removed in the compositor to simplify the compositing
workflow. This introduced a slight inconsistency with the Shader Node
Editor.
This PR removes "Use Nodes" for object materials.
For Line Style, no changes are planned (not sure how to preserve
compatibility yet).
This simplifies the state of objects; either they have a material or
they don't.
Backward compatibility:
- If Use Nodes is turned Off, new nodes are added to the node tree to
simulate the same material:
- DNA: Only `use_nodes` is marked deprecated
- Python API:
- `material.use_nodes` is marked deprecated and will be removed in
6.0. Reading it always returns `True` and setting it has no effect.
- `material.diffuse_color`, `material.specular` etc.. Are not used by
EEVEE anymore but are kept because they are used by Workbench.
Forward compatibility:
Always enable 'Use Nodes' when writing blend files.
Known Issues:
Some UI tests are failing on macOS
Pull Request: https://projects.blender.org/blender/blender/pulls/141278
Part of https://projects.blender.org/blender/blender/pulls/141278
Blend files compatibility:
If a World exists and "Use Nodes" is disabled, we add new nodes to the
existing node tree (or create one if it doesn't) that emulates the
behavior of a world without a node tree. This ensures backward and
forward compatibility.
Python API compatibility:
- `world.use_nodes` was removed from Python API => **Breaking change**
- `world.color` is still being used by Workbench, so it stays there,
although it has no effect anymore when using Cycles or EEVEE.
Python API changes:
Creating a World using `bpy.data.worlds.new()` now creates a World with
an empty (embedded) node tree. This was necessary to enable Python
scripts to add nodes without having to create a node tree (which is
currently not possible, because World node trees are embedded).
Pull Request: https://projects.blender.org/blender/blender/pulls/142342
This changes the engine identifier back to `BLENDER_EEVEE`.
We keep the `BLENDER_EEVEE_NEXT` identifier around for
versioning reasons (have to detect when it is the active
engine of a older file).
This also rename a bunch of pannels that were using `next`
in their name.
This is a breaking change for Addons compatibility.
Pull Request: https://projects.blender.org/blender/blender/pulls/140282
Remove arrow from "Operating system" pointing to "Other Directories".
The other directories are for context and aren't called into.
Also correct a typo.
