Design: https://projects.blender.org/blender/blender/issues/126032
The brush assets project merged all brush based tools into a single, "Brush"
tool. After feedback, we want to bring back some of the previous brush based
tools. For example in grease pencil draw mode, not having an eraser or fill tool
available, and having to go through all the brush assets instead made the
workflow more cumbersome, and features less discoverable (an eraser tool in the
toolbar is quite easy to find, a brush deep down in the asset library may not
be).
With this commit we can add back some tools for specific brush types in sculpt &
paint modes. The follow up commit will start with the eraser and fill tools for
grease pencil draw mode, but more tools in other modes are expected to follow.
For every brush type that has a tool in the toolbar, the last used brush is
remembered. This is the biggest part of the changes here.
Brush asset popups will only show the brushes supported by the active tool for
now. The permanent asset shelf region displays all brushes. Activating a brush
that isn't compatible with the current tool will also activate the general
"Brush" tool, but while the brush tool is active we never switch to another one
(e.g. activating an eraser brush will keep the "Brush" tool active). All this
might change after further feedback.
Pull Request: https://projects.blender.org/blender/blender/pulls/125449
Part of blender/blender!125449.
Since brush assets were merged, the brush asset selector and some other brush
UIs wouldn't show up for the primitive tools. This is addressed now. The
primitive tools use the same brush as the brush tool, although only the draw
brushes will work properly. !125449 addresses this so the primitive tools
remember their own draw brush, separate from the brush tool.
Turns out that these primitive tools were never tagged as using brushes by
setting the `data_block` member (or setting the `'USE_BRUSHES'` option since
b64bf66257). The UI was just hardcoded to display things like the brush selector
for primitive tools. So as far as the tool system knew, these tools did not use
brushes.
Tagging the tools properly exposed some issues that are addressed here (see PR
for details).
Pull Request: https://projects.blender.org/blender/blender/pulls/127204
Pass the context using const where it makes sense. Had some own code
that called some of these functions, so I had to keep context non-const
there too for no good reason.
