In order to address feedback that the "Stable ID" was not easy enough
to use, remove the "Stable ID" output from the distribution node and
the input from the instance on points node. Instead, the nodes write
or read a builtin named attribute called `id`. In the future we may
add more attributes like `edge_id` and `face_id`.
The downside is that more behavior is invisible, which is les
expected now that most attributes are passed around with node links.
This behavior will have to be explained in the manual.
The random value node's "ID" input that had an implicit index input
is converted to a special implicit input that uses the `id` attribute
if possible, but otherwise defaults to the index. There is no way to
tell in the UI which it uses, except by knowing that rule and checking
in the spreadsheet for the id attribute.
Because it isn't always possible to create stable randomness, this
attribute does not always exist, and it will be possible to remove it
when we have the attribute remove node back, to improve performance.
Differential Revision: https://developer.blender.org/D12903
This commit exposes left and right bezier handles as an attribute.
Interaction basically works like edit mode. If you move an aligned
handle, it also moves the opposite handle of the control point.
The difference is that you can't edit "Auto" or "Vector" handles,
you have to first use the "Set Handle Type" node. That gives the handle
types a bit more meaning in the node tree-- changing them in edit mod
is more like a "UI override".
The attributes are named `handle_start` and `handle_end`,
which is the same name used in the curve RNA API.
A new virtual array implementation is added which handles the case of
splines that don't have these attributes, and it also calls two new
functions on `BezierSpline` to set the handle position accounting
for aligned handles.
The virtual arrays and attribute providers will be refactored
(probably templated) in the future, as a next step after the last
built-in curve attribute provider has landed.
Differential Revision: https://developer.blender.org/D12005
The generic domain interpolation algorithms didn't quite work for
selections. The interpolation would do unexpected things that
were different than the results in edit mode. The new behavior
is supposed to be the same as edit mode, although we also have
to handle face corner selections here.
Currently the code assumes that all boolean attributes should be
handled that way. I'm not sure of why that wouldn't be the case,
but if we ever need non-selection boolean attributes, that could
be supported too.
Differential Revision: https://developer.blender.org/D12488
With this commit, curve objects support the geometry nodes modifier.
Curves objects now evaluate to `CurveEval` unless there was a previous
implicit conversion (tessellating modifiers, mesh modifiers, or the
settings in the curve "Geometry" panel). In the new code, curves are
only considered to be the wire edges-- any generated surface is a mesh
instead, stored in the evaluated geometry set.
The consolidation of concepts mentioned above allows remove a lot of
code that had to do with maintaining the `DispList` type temporarily
for modifiers and rendering. Instead, render engines see a separate
object for the mesh from the mesh geometry component, and when the
curve object evaluates to a curve, the `CurveEval` is always used for
drawing wire edges.
However, currently the `DispList` type is still maintained and used as
an intermediate step in implicit mesh conversion. In the future, more
uses of it could be changed to use `CurveEval` and `Mesh` instead.
This is mostly not changed behavior, it is just a formalization of
existing logic after recent fixes for 2.8 versions last year and two
years ago. Also, in the future more functionality can be converted
to nodes, removing cases of implicit conversions. For more discussion
on that topic, see T89676.
The `use_fill_deform` option is removed. It has not worked properly
since 2.62, and the choice for filling a curve before or after
deformation will work much better and be clearer with a node system.
Applying the geometry nodes modifier to generate a curve is not
implemented with this commit, so applying the modifier won't work
at all. This is a separate technical challenge, and should be solved
in a separate step.
Differential Revision: https://developer.blender.org/D11597
This implements the initial core framework for fields and anonymous
attributes (also see T91274).
The new functionality is hidden behind the "Geometry Nodes Fields"
feature flag. When enabled in the user preferences, the following
new nodes become available: `Position`, `Index`, `Normal`,
`Set Position` and `Attribute Capture`.
Socket inspection has not been updated to work with fields yet.
Besides these changes at the user level, this patch contains the
ground work for:
* building and evaluating fields at run-time (`FN_fields.hh`) and
* creating and accessing anonymous attributes on geometry
(`BKE_anonymous_attribute.h`).
For evaluating fields we use a new so called multi-function procedure
(`FN_multi_function_procedure.hh`). It allows composing multi-functions
in arbitrary ways and supports efficient evaluation as is required by
fields. See `FN_multi_function_procedure.hh` for more details on how
this evaluation mechanism can be used.
A new `AttributeIDRef` has been added which allows handling named
and anonymous attributes in the same way in many places.
Hans and I worked on this patch together.
Differential Revision: https://developer.blender.org/D12414
This patch adds relatively small changes to the curve draw
cache implementation in order to draw the curve data in the
viewport. The dependency graph iterator is also modified
so that it iterates over the curve geometry component, which
is presented to users as `Curve` data with a pointer to the
`CurveEval`
The idea with the spline data type in geometry nodes is that
curve data itself is only the control points, and any evaluated
data with faces is a mesh. That is mostly expected elsewhere in
Blender anyway. This means it's only necessary to implement
wire edge drawing of `CurveEval` data.
Adding a `CurveEval` pointer to `Curve` is in line with changes
I'd like to make in the future like using `CurveEval` in more places
such as edit mode.
An alternate solution involves converting the curve wire data
to a mesh, however, that requires copying all of the data, and
since avoiding it is rather simple and is in-line with future plans
anyway, I think doing it this way is better.
Differential Revision: https://developer.blender.org/D11351
This commit adds interpolation from the point domain to the spline
domain and the other way around. Before this, spline domain attributes
were basically useless, but now they are quite helpful as a way to use
a shared value in a contiguous group of points.
I implementented a special virtual array for the spline to points
conversion, so that conversion should be close to the ideal performance
level, but there are a few ways we could optimize the point to spline
conversion in the future:
- Use a function virtual array to mix the point values for each spline
on demand.
- Implement a special case for when the input virtual array is one of
the virtual arrays from the spline point attributes. In other words,
decrease curve attribute access overhead.
Differential Revision: https://developer.blender.org/D11376
With this patch you will be able to add and remove attributes from curve
data inside of geometry nodes. The following is currently implemented:
* Adding attributes with any data type to splines or spline points.
* Support for working with multiple splines at the same time.
* Interaction with the three builtin point attributes.
* Resampling attributes in the resample node.
The following is not implemented in this patch:
* Joining attributes when joining splines with the join geometry node.
* Domain interpolation between spline and point domains.
* More efficient ways to call attribute operations once per spline.
Differential Revision: https://developer.blender.org/D11251
Not allowing external direct access to the vector of splines in the
curve will help for things like reallocating custom data when a spline
is added or removed.
This commit exposes the first spline control point attributes. The
implementation incorporates the attributes into the virtual array
system, providing efficient methods to flatten the data into a
contiguous array and to apply changes from a flattened array. This
is only part of the eventual goal, which includes changes to run
attribute nodes separately for each spline to completely avoid copying.
So far `tilt` and `radius`, the two generic attributes common to
all spline types, are implemented. The more complex `position`
attribute is also added. It requires some special handling for Bezier
splines, where the control point handles need to be moved along with
the control points. To make that work I also added automatic handle
recalculation to the Bezier spline.
Differential Revision: https://developer.blender.org/D11187
This patch adds initial curve support to geometry nodes. Currently
there is only one node available, the "Curve to Mesh" node, T87428.
However, the aim of the changes here is larger than just supporting
curve data in nodes-- it also uses the opportunity to add better spline
data structures, intended to replace the existing curve evaluation code.
The curve code in Blender is quite old, and it's generally regarded as
some of the messiest, hardest-to-understand code as well. The classes
in `BKE_spline.hh` aim to be faster, more extensible, and much more
easily understandable. Further explanation can be found in comments in
that file.
Initial builtin spline attributes are supported-- reading and writing
from the `cyclic` and `resolution` attributes works with any of the
attribute nodes. Also, only Z-up normal calculation is implemented
at the moment, and tilts do not apply yet.
**Limitations**
- For now, you must bring curves into the node tree with an "Object
Info" node. Changes to the curve modifier stack will come later.
- Converting to a mesh is necessary to visualize the curve data.
Further progress can be tracked in: T87245
Higher level design document: https://wiki.blender.org/wiki/Modules/Physics_Nodes/Projects/EverythingNodes/CurveNodes
Differential Revision: https://developer.blender.org/D11091
