Previously, the lifetimes of anonymous attributes were determined by
reference counts which were non-deterministic when multiple threads
are used. Now the lifetimes of anonymous attributes are handled
more explicitly and deterministically. This is a prerequisite for any kind
of caching, because caching the output of nodes that do things
non-deterministically and have "invisible inputs" (reference counts)
doesn't really work.
For more details for how deterministic lifetimes are achieved, see D16858.
No functional changes are expected. Small performance changes are expected
as well (within few percent, anything larger regressions should be reported as
bugs).
Differential Revision: https://developer.blender.org/D16858
This is the last node to use the `CurveEval` type. Since the curve to
points node is basically the same as the resample node, now it just
reuses the resample code and moves the curve point `CustomData` to a
new point cloud at the end. I had to add support for sampling tangents
and normals to the resampling.
There is one behavior change: If the radius attribute doesn't exist,
the node won't set the radius to 1 for the output point cloud anymore.
Instead, the default radius for point clouds will be used.
That issue was similar to T99814.
Differential Revision: https://developer.blender.org/D16008
Using the same `GeometryComponentFieldContext` for all situations,
even when only one geometry type is supported is misleading, and mixes
too many different abstraction levels into code that could be simpler.
With the attribute API moved out of geometry components recently,
the "component" system is just getting in the way here.
This commit adds specific field contexts for geometry types: meshes,
curves, point clouds, and instances. There are also separate field input
helper classes, to help reduce boilerplate for fields that only support
specific geometry types.
Another benefit of this change is that it separates geometry components
from fields, which makes it easier to see the purpose of the two concepts,
and how they relate.
Because we want to be able to evaluate a field on just `CurvesGeometry`
rather than the full `Curves` data-block, the generic "geometry context"
had to be changed to avoid using `GeometryComponent`, since there is
no corresponding geometry component type. The resulting void pointer
is ugly, but only turns up in three places in practice. When Apple clang
supports `std::variant`, that could be used instead.
Differential Revision: https://developer.blender.org/D15519
