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, 14 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/attribute_access.cc b/source/blender/blenkernel/intern/attribute_access.cc
index 3b2ee126d91..571763e3719 100644
--- a/source/blender/blenkernel/intern/attribute_access.cc
+++ b/source/blender/blenkernel/intern/attribute_access.cc
@@ -729,6 +729,20 @@ bool GeometryComponent::attribute_exists(const blender::StringRef attribute_name
   return false;
 }
 
+std::optional<AttributeMetaData> GeometryComponent::attribute_get_meta_data(
+    const StringRef attribute_name) const
+{
+  std::optional<AttributeMetaData> result{std::nullopt};
+  this->attribute_foreach([&](StringRefNull name, const AttributeMetaData &meta_data) {
+    if (attribute_name == name) {
+      result = meta_data;
+      return false;
+    }
+    return true;
+  });
+  return result;
+}
+
 static std::unique_ptr<blender::fn::GVArray> try_adapt_data_type(
     std::unique_ptr<blender::fn::GVArray> varray, const blender::fn::CPPType &to_type)
 {