Geometry Nodes: Get attribute domain and type without allocation

Because we use virtual classes (and for other reasons), we had to do a
small allocation when simply retrieving the data type and domain of an
existing attribute. This happened quite a lot actually-- to determine
these values for result attributes.

This patch adds a simple function to retrieve this meta data without
building the virtual array. This should lower the overhead of every
attribute node, though the difference probably won't be noticible
unless a tree has very many nodes.

Differential Revision: https://developer.blender.org/D11047

1 files changed, 4 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_geometry_set.hh b/source/blender/blenkernel/BKE_geometry_set.hh
index 38f692fee0e..e9545cba1f1 100644
--- a/source/blender/blenkernel/BKE_geometry_set.hh
+++ b/source/blender/blenkernel/BKE_geometry_set.hh
@@ -102,6 +102,10 @@ class GeometryComponent {
   /* Return true when any attribute with this name exists, including built in attributes. */
   bool attribute_exists(const blender::StringRef attribute_name) const;
 
+  /* Return the data type and domain of an attribute with the given name if it exists. */
+  std::optional<AttributeMetaData> attribute_get_meta_data(
+      const blender::StringRef attribute_name) const;
+
   /* Returns true when the geometry component supports this attribute domain. */
   bool attribute_domain_supported(const AttributeDomain domain) const;
   /* Can only be used with supported domain types. */