While we do need higher level utilities for copying attributes
between geometries, this currently isn't used and it's not clear
that it will be the right abstraction in the end.
This moves all multi-function related code in the `functions` module
into a new `multi_function` namespace. This is similar to how there
is a `lazy_function` namespace.
The main benefit of this is that many types names that were prefixed
with `MF` (for "multi function") can be simplified.
There is also a common shorthand for the `multi_function` namespace: `mf`.
This is also similar to lazy-functions where the shortened namespace
is called `lf`.
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
The instance attributes assignment operators were broken in multiple
ways: there wasn't a move constructor (probably causing performance
issues), and the destination attributes weren't freed before they
were replaced.
The typed "lookup_or_add_for_write_only" function is meant to do the
same thing as the non-typed version of the function. Instead, it still
initialized values of new attribute arrays, which isn't meant to happen.
Missed in 4c91c24bc7.
I also had to correct one place that used the "write_only"
function but didn't intialize all values.
I didn't observe this issue in practice, but since the write_only
version of the attribute API isn't meant to initialize trivial types,
theoretically this could be a problem if the attribute is created
halfway through converting the BMesh to a Mesh.
We expect some builtin attributes to have positive values or values
within a certain range, but currently there some cases where users
can set attributes to arbitrary values: the store named attribute node,
and the output attributes of the geometry nodes modifier. The set
material index node also needs validation.
This patch adds an `AttributeValidator` to the attribute API, which
can be used to correct values from these untrusted inputs if necessary.
As an alternative to D15548, this approach makes it much easier to
understand when validation is being applied, without the need to add
arguments to every attribute API method or complicate the virtual
array system.
Currently validation is provided with a multi-function. That integrates
well with the field evaluations that set these values now, but it could
be wrapped to be friendlier to other areas of Blender in the future.
The Python API is not handled here either. Currently I would prefer to
wait until we can integrate the C++ and C attribute APIs better before
addressing that.
Fixes T100952
Differential Revision: https://developer.blender.org/D15990
The trim functionality is implemented in the geometry module, and
generalized a bit to be potentially useful for bisecting in the future.
The implementation is based on a helper type called `IndexRangeCyclic`
which allows iteration over all control points between two points on a
curve.
Catmull Rom curves are now supported-- trimmed without resampling first.
However, maintaining the exact shape is not possible. NURBS splines are
still converted to polylines using the evaluated curve concept.
Performance is equivalent or faster then a 3.1 build with regards to
node timings. Compared to 3.3 and 3.2, it's easy to observe test cases
where the node is at least 3 or 4 times faster.
Differential Revision: https://developer.blender.org/D14481
Replace `mesh_attributes`, `mesh_attributes_for_write` and the point
cloud versions with methods on the `Mesh` and `PointCloud` types.
This makes them friendlier to use and improves readability.
Differential Revision: https://developer.blender.org/D15907
When allocating new `CustomData` layers, often we do redundant
initialization of arrays. For example, it's common that values are
allocated, set to their default value, and then set to some other
value. This is wasteful, and it negates the benefits of optimizations
to the allocator like D15082. There are two reasons for this. The
first is array-of-structs storage that makes it annoying to initialize
values manually, and the second is confusing options in the Custom Data
API. This patch addresses the latter.
The `CustomData` "alloc type" options are rearranged. Now, besides
the options that use existing layers, there are two remaining:
* `CD_SET_DEFAULT` sets the default value.
* Usually zeroes, but for colors this is white (how it was before).
* Should be used when you add the layer but don't set all values.
* `CD_CONSTRUCT` refers to the "default construct" C++ term.
* Only necessary or defined for non-trivial types like vertex groups.
* Doesn't do anything for trivial types like `int` or `float3`.
* Should be used every other time, when all values will be set.
The attribute API's `AttributeInit` types are updated as well.
To update code, replace `CD_CALLOC` with `CD_SET_DEFAULT` and
`CD_DEFAULT` with `CD_CONSTRUCT`. This doesn't cause any functional
changes yet. Follow-up commits will change to avoid initializing
new layers where the correctness is clear.
Differential Revision: https://developer.blender.org/D15617
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
Calling `finish` after writing to generic attributes is currently necessary for
correctness. Previously, this was easy to forget. Now there is a check for this
in debug builds.
Use the attribute API instead of the CustomData API, to correctly
handle anonymous attributes and simplify the code. One non-obvious
thing to note is that the type counts are recalculated by the "finish"
function of the `curve_type` attribute, so they don't need to be copied
explicitly. Also, the mutable attribute accessor cannot be an reference
if we want to give it an rvalue, which is convenient in this case.
This commit ports the fillet curves node to the new curves data-block,
and moves the fillet node implementation to the geometry module to help
separate the implementation from the node.
The changes are similar to the subdivide node or resample node. I've
resused common utilities where it makes sense, though some things like
the iteration over attributes can be generalized further. The node
is now multi-threaded per-curve and inside each curve, and some buffers
are reused per curve to avoid many allocations.
The code is more explicit now, and though there is more boilerplate to
pass around many spans, the more complex logic should be more readable.
Differential Revision: https://developer.blender.org/D15346
Currently, there are two attribute API. The first, defined in `BKE_attribute.h` is
accessible from RNA and C code. The second is implemented with `GeometryComponent`
and is only accessible in C++ code. The second is widely used, but only being
accessible through the `GeometrySet` API makes it awkward to use, and even impossible
for types that don't correspond directly to a geometry component like `CurvesGeometry`.
This patch adds a new attribute API, designed to replace the `GeometryComponent`
attribute API now, and to eventually replace or be the basis of the other one.
The basic idea is that there is an `AttributeAccessor` class that allows code to
interact with a set of attributes owned by some geometry. The accessor itself has
no ownership. `AttributeAccessor` is a simple type that can be passed around by
value. That makes it easy to return it from functions and to store it in containers.
For const-correctness, there is also a `MutableAttributeAccessor` that allows
changing individual and can add or remove attributes.
Currently, `AttributeAccessor` is composed of two pointers. The first is a pointer
to the owner of the attribute data. The second is a pointer to a struct with
function pointers, that is similar to a virtual function table. The functions
know how to access attributes on the owner.
The actual attribute access for geometries is still implemented with the `AttributeProvider`
pattern, which makes it easy to support different sources of attributes on a
geometry and simplifies dealing with built-in attributes.
There are different ways to get an attribute accessor for a geometry:
* `GeometryComponent.attributes()`
* `CurvesGeometry.attributes()`
* `bke::mesh_attributes(const Mesh &)`
* `bke::pointcloud_attributes(const PointCloud &)`
All of these also have a `_for_write` variant that returns a `MutabelAttributeAccessor`.
Differential Revision: https://developer.blender.org/D15280
