diff options
author | Jacques Lucke <jacques@blender.org> | 2022-07-08 17:16:56 +0300 |
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committer | Jacques Lucke <jacques@blender.org> | 2022-07-08 17:16:56 +0300 |
commit | b876ce2a4a4638142439a7cf265a0780491ae4cc (patch) | |
tree | 871d71eb6d1cf215869fc941c831c81bcacc6433 /source/blender/io | |
parent | f391e8f316bd29b700cef874a59cf3b64203d70c (diff) |
Geometry Nodes: new geometry attribute API
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
Diffstat (limited to 'source/blender/io')
-rw-r--r-- | source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc index cb95c561547..731587bfcea 100644 --- a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc +++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc @@ -254,9 +254,8 @@ void OBJWriter::write_vertex_coords(FormatHandler<eFileType::OBJ> &fh, colors_layer = BKE_id_attributes_active_color_get(&mesh->id); } if (write_colors && (colors_layer != nullptr)) { - MeshComponent component; - component.replace(mesh, GeometryOwnershipType::ReadOnly); - VArray<ColorGeometry4f> attribute = component.attribute_get_for_read<ColorGeometry4f>( + const bke::AttributeAccessor attributes = bke::mesh_attributes(*mesh); + const VArray<ColorGeometry4f> attribute = attributes.lookup_or_default<ColorGeometry4f>( colors_layer->name, ATTR_DOMAIN_POINT, {0.0f, 0.0f, 0.0f, 0.0f}); BLI_assert(tot_count == attribute.size()); |