Geometry Nodes: Add Attribute Convert node

The Attribute Convert node provides functionality to change attributes
between different domains and data types. Before it was impossible to
write to a UV Map attribute with the attribute math nodes since they
did not output a 2D vector type. This makes it possible to
"convert into" a UV map attribute.

The data type conversion uses the implicit conversions provided by
`\nodes\intern\node_tree_multi_function.cc`.

The `Auto` domain mode chooses the domain based on the following rules:
1. If the result attribute already exists, use that domain.
2. If the result attribute doesn't exist, use the source attribute domain.
3. Otherwise use the default domain (points).

See {T85700}

Differential Revision: https://developer.blender.org/D10624

3 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_attribute.h b/source/blender/blenkernel/BKE_attribute.h
index 574d9904dc4..a98bfd1e3df 100644
--- a/source/blender/blenkernel/BKE_attribute.h
+++ b/source/blender/blenkernel/BKE_attribute.h
@@ -39,6 +39,7 @@ struct ReportList;
 
 /* Attribute.domain */
 typedef enum AttributeDomain {
+  ATTR_DOMAIN_AUTO = -1,   /* Use for nodes to choose automatically based on other data. */
   ATTR_DOMAIN_POINT = 0,   /* Mesh, Hair or PointCloud Point */
   ATTR_DOMAIN_EDGE = 1,    /* Mesh Edge */
   ATTR_DOMAIN_CORNER = 2,  /* Mesh Corner */
diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index 2c543a0a014..0379dea9e8c 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -1373,6 +1373,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_ATTRIBUTE_SEPARATE_XYZ 1028
 #define GEO_NODE_SUBDIVIDE 1029
 #define GEO_NODE_ATTRIBUTE_REMOVE 1030
+#define GEO_NODE_ATTRIBUTE_CONVERT 1031
 
 /** \} */
 
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 528088b2ee7..156f6a0c7ae 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -4788,6 +4788,7 @@ static void registerGeometryNodes()
   register_node_type_geo_attribute_color_ramp();
   register_node_type_geo_attribute_combine_xyz();
   register_node_type_geo_attribute_compare();
+  register_node_type_geo_attribute_convert();
   register_node_type_geo_attribute_fill();
   register_node_type_geo_attribute_math();
   register_node_type_geo_attribute_mix();