2 files changed, 46 insertions, 1 deletions

diff --git a/source/blender/nodes/geometry/node_geometry_util.cc b/source/blender/nodes/geometry/node_geometry_util.cc
index 34c7d224f03..f9ded0e1995 100644
--- a/source/blender/nodes/geometry/node_geometry_util.cc
+++ b/source/blender/nodes/geometry/node_geometry_util.cc
@@ -36,6 +36,48 @@ void update_attribute_input_socket_availabilities(bNode &node,
   }
 }
 
+static int attribute_data_type_complexity(const CustomDataType data_type)
+{
+  switch (data_type) {
+    case CD_PROP_BOOL:
+      return 0;
+    case CD_PROP_FLOAT:
+      return 2;
+    case CD_PROP_FLOAT3:
+      return 4;
+    case CD_PROP_COLOR:
+      return 5;
+#if 0 /* Attribute types are not supported yet. */
+    case CD_PROP_INT32:
+      return 1;
+    case CD_MLOOPCOL:
+      return 3;
+    case CD_PROP_STRING:
+      return 6;
+#endif
+    default:
+      /* Only accept "generic" custom data types used by the attribute system. */
+      BLI_assert(false);
+      return 0;
+  }
+}
+
+CustomDataType attribute_domain_lowest_complexity(Span<CustomDataType> data_types)
+{
+  int lowest_complexity = INT_MAX;
+  CustomDataType least_complex_type = CD_PROP_BOOL;
+
+  for (const CustomDataType data_type : data_types) {
+    const int complexity = attribute_data_type_complexity(data_type);
+    if (complexity < lowest_complexity) {
+      lowest_complexity = complexity;
+      least_complex_type = data_type;
+    }
+  }
+
+  return least_complex_type;
+}
+
 }  // namespace blender::nodes
 
 bool geo_node_poll_default(bNodeType *UNUSED(ntype), bNodeTree *ntree)
diff --git a/source/blender/nodes/geometry/node_geometry_util.hh b/source/blender/nodes/geometry/node_geometry_util.hh
index ec389961615..b8728016230 100644
--- a/source/blender/nodes/geometry/node_geometry_util.hh
+++ b/source/blender/nodes/geometry/node_geometry_util.hh
@@ -42,4 +42,7 @@ namespace blender::nodes {
 void update_attribute_input_socket_availabilities(bNode &node,
                                                   const StringRef name,
                                                   const GeometryNodeAttributeInputMode mode);
-}
+
+CustomDataType attribute_domain_lowest_complexity(Span<CustomDataType>);
+
+}  // namespace blender::nodes
\ No newline at end of file