Geometry Nodes: Split transfer attribute node

This patch replaces the existing transfer attribute node with three
nodes, "Sample Nearest Surface", "Sample Index", and "Sample Nearest".
This follows the design in T100010, allowing for new nodes like UV
sampling in the future. There is versioning so the new nodes replace
the old ones and are relinked as necessary.

The "Sample Nearest Surface" node is meant for the more complex
sampling algorithms that only work on meshes and interpolate
values inside of faces.

The new "Sample Index" just retrieves attributes from a geometry at
specific indices. It doesn't have implicit behavior like the old
transfer mode, which should make it more predictable. In order to not
change the behavior from existing files, the node has a has a "Clamp",
which is off by default for consistency with the "Field at Index" node.

The "Sample Nearest" node returns the index of the nearest element
on a geometry. It can be combined with the "Sample Index" node for
the same functionality as the old transfer node. This node can support
curves in the future.

Backwards compatibility is handled by versioning, but old versions can
not understand these nodes. The warning from 680fa8a523e0 should make
this explicit in 3.3 and earlier.

Differential Revision: https://developer.blender.org/D15909

1 files changed, 35 insertions, 44 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 892d523bdcf..bdf68dea67b 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -2199,18 +2199,6 @@ static const EnumPropertyItem *rna_GeometryNodeAttributeType_type_with_socket_it
                               generic_attribute_type_supported_with_socket);
 }
 
-static bool transfer_attribute_type_supported(const EnumPropertyItem *item)
-{
-  return ELEM(
-      item->value, CD_PROP_FLOAT, CD_PROP_FLOAT3, CD_PROP_COLOR, CD_PROP_BOOL, CD_PROP_INT32);
-}
-static const EnumPropertyItem *rna_NodeGeometryTransferAttribute_type_itemf(
-    bContext *UNUSED(C), PointerRNA *UNUSED(ptr), PropertyRNA *UNUSED(prop), bool *r_free)
-{
-  *r_free = true;
-  return itemf_function_check(rna_enum_attribute_type_items, transfer_attribute_type_supported);
-}
-
 static bool attribute_statistic_type_supported(const EnumPropertyItem *item)
 {
   return ELEM(item->value, CD_PROP_FLOAT, CD_PROP_FLOAT3);
@@ -10424,50 +10412,53 @@ static void def_geo_curve_trim(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 }
 
-static void def_geo_transfer_attribute(StructRNA *srna)
+static void def_geo_sample_index(StructRNA *srna)
 {
-  static EnumPropertyItem mapping_items[] = {
-      {GEO_NODE_ATTRIBUTE_TRANSFER_NEAREST_FACE_INTERPOLATED,
-       "NEAREST_FACE_INTERPOLATED",
-       0,
-       "Nearest Face Interpolated",
-       "Transfer the attribute from the nearest face on a surface (loose points and edges are "
-       "ignored)"},
-      {GEO_NODE_ATTRIBUTE_TRANSFER_NEAREST,
-       "NEAREST",
-       0,
-       "Nearest",
-       "Transfer the element from the nearest element (using face and edge centers for the "
-       "distance computation)"},
-      {GEO_NODE_ATTRIBUTE_TRANSFER_INDEX,
-       "INDEX",
-       0,
-       "Index",
-       "Transfer the data from the element with the corresponding index in the target geometry"},
-      {0, NULL, 0, NULL, NULL},
-  };
-
   PropertyRNA *prop;
 
-  RNA_def_struct_sdna_from(srna, "NodeGeometryTransferAttribute", "storage");
-
-  prop = RNA_def_property(srna, "mapping", PROP_ENUM, PROP_NONE);
-  RNA_def_property_enum_sdna(prop, NULL, "mode");
-  RNA_def_property_enum_items(prop, mapping_items);
-  RNA_def_property_ui_text(prop, "Mapping", "Mapping between geometries");
-  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+  RNA_def_struct_sdna_from(srna, "NodeGeometrySampleIndex", "storage");
 
   prop = RNA_def_property(srna, "data_type", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, rna_enum_attribute_type_items);
-  RNA_def_property_enum_funcs(prop, NULL, NULL, "rna_NodeGeometryTransferAttribute_type_itemf");
+  RNA_def_property_enum_funcs(
+      prop, NULL, NULL, "rna_GeometryNodeAttributeType_type_with_socket_itemf");
   RNA_def_property_enum_default(prop, CD_PROP_FLOAT);
-  RNA_def_property_ui_text(prop, "Data Type", "The type for the source and result data");
+  RNA_def_property_ui_text(prop, "Data Type", "");
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 
   prop = RNA_def_property(srna, "domain", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, rna_enum_attribute_domain_items);
   RNA_def_property_enum_default(prop, ATTR_DOMAIN_POINT);
-  RNA_def_property_ui_text(prop, "Domain", "The domain to use on the target geometry");
+  RNA_def_property_ui_text(prop, "Domain", "");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
+
+  prop = RNA_def_property(srna, "clamp", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_ui_text(prop,
+                           "Clamp",
+                           "Clamp the indices to the size of the attribute domain instead of "
+                           "outputting a default value for invalid indices");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
+}
+
+static void def_geo_sample_nearest_surface(StructRNA *srna)
+{
+  PropertyRNA *prop = RNA_def_property(srna, "data_type", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "custom1");
+  RNA_def_property_enum_items(prop, rna_enum_attribute_type_items);
+  RNA_def_property_enum_funcs(
+      prop, NULL, NULL, "rna_GeometryNodeAttributeType_type_with_socket_itemf");
+  RNA_def_property_enum_default(prop, CD_PROP_FLOAT);
+  RNA_def_property_ui_text(prop, "Data Type", "");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+}
+
+static void def_geo_sample_nearest(StructRNA *srna)
+{
+  PropertyRNA *prop = RNA_def_property(srna, "domain", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "custom2");
+  RNA_def_property_enum_items(prop, rna_enum_attribute_domain_only_mesh_items);
+  RNA_def_property_enum_default(prop, ATTR_DOMAIN_POINT);
+  RNA_def_property_ui_text(prop, "Domain", "");
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
 }