This allows accessing attribute meta data like domain and data type
without having to create a `ReadAttribute`. I kept the `attribute_names`
method for now to keep the patch more self contained.
Differential Revision: https://developer.blender.org/D10511
"Kind" is a bit less generic than "Info" for me. Especially, it implies
that the struct does not contain the name of a specific attribute
(for me anyway).
Previously, when a Geometry Nodes modifier outputs a point cloud
(e.g. generated using the Point Distribute node), other modifiers
could not use that data. Now, the point cloud data is converted to
mesh vertices for such modifiers.
Ref T85281.
Differential Revision: https://developer.blender.org/D10451
The `material_index` attribute can adjust which material in the list
will be applied to each face of the mesh. There are two new things
about this attribute that haven't been exposed by the attribute API yet.
Each comes with limitations:
1. Integer data type: Most attribute nodes are currently written to use
float data types. This means that they can't write to this attribute
because they can't change the type of a built-in attribute.
2. Polygon domain: This is our first attribute using the polygon domain,
meaning until some of the interpolations are implemented, some
operations may not work as expected.
Currently the two nodes that work with this attribute are Attribute Fill
and Attribute Randomize.
Differential Revision: https://developer.blender.org/D10444
In an upcoming commit I'll also move the make-instances-real functionality
to this file. This code is not essential to working with geometry sets in general,
so it makes sense to move it to a separate header.
