This patch introduces the `Plane` brush, a generalization of the
existing `Flatten`, `Fill` and `Scrape` brushes, with the objective of
providing more flexibility when sculpting.
This brush has the following key features:
* `Height` and `Depth` parameters to control the range of the brush in
the local z-axis.
* Stabilizers for the normal and center of the brush plane.
When inverting, the user can choose between two options:
* `Invert Displacement`: Identical to the existing behavior, displacing
vertices away from the plane.
* `Swap Height and Depth`: Exchanges the roles of `Height` and `Depth`.
For example a brush with `Height` = 0.7 and `Depth` = 0.3 behaves as
if it had `Height` = 0.3 and `Depth` = 0.7. In particular, this
ensures that a scrape brush (`Height` = 1, `Depth` = 0) becomes
equivalent to a fill brush (`Height` = 0, `Depth` = 1) when inverted,
and viceversa.
In the existing planar brushes, the influence on a vertex is determined
by the 3D Euclidean distance between the vertex and the cursor position,
multiplied by the vertex's distance from the brush plane (and other
factors common to all brushes).
In the `Plane` brush, the 3D distance is between the vertex and the
plane center instead of the cursor position.
The Plane brush introduces two parameters — `Stabilize Normal` and
`Stabilize Plane`. These can be thought of as the non-binary version of
the `Original Normal` and `Original Plane` options found in existing
brushes. These values are a weighted moving average across a window of
previous stroke steps.
Pull Request: https://projects.blender.org/blender/blender/pulls/132723
6f80dba66c