Geometry Nodes: Instance attributes in Transfer/Capture nodes

Updates the Transfer Attributes and Capture Attributes nodes
to support attributes from instances.

Differential Revision: https://developer.blender.org/D13292

2 files changed, 28 insertions, 18 deletions

diff --git a/source/blender/nodes/geometry/nodes/node_geo_attribute_capture.cc b/source/blender/nodes/geometry/nodes/node_geo_attribute_capture.cc
index 19deb761948..1cb26646d5a 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_attribute_capture.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_attribute_capture.cc
@@ -147,16 +147,27 @@ static void geo_node_attribute_capture_exec(GeoNodeExecParams params)
   WeakAnonymousAttributeID anonymous_id{"Attribute"};
   const CPPType &type = field.cpp_type();
 
-  static const Array<GeometryComponentType> types = {
-      GEO_COMPONENT_TYPE_MESH, GEO_COMPONENT_TYPE_POINT_CLOUD, GEO_COMPONENT_TYPE_CURVE};
-  geometry_set.modify_geometry_sets([&](GeometrySet &geometry_set) {
-    for (const GeometryComponentType type : types) {
-      if (geometry_set.has(type)) {
-        GeometryComponent &component = geometry_set.get_component_for_write(type);
-        try_capture_field_on_geometry(component, anonymous_id.get(), domain, field);
-      }
+  /* Run on the instances component separately to only affect the top level of instances. */
+  if (domain == ATTR_DOMAIN_INSTANCE) {
+    if (geometry_set.has_instances()) {
+      GeometryComponent &component = geometry_set.get_component_for_write(
+          GEO_COMPONENT_TYPE_INSTANCES);
+      try_capture_field_on_geometry(component, anonymous_id.get(), domain, field);
     }
-  });
+  }
+  else {
+    static const Array<GeometryComponentType> types = {
+        GEO_COMPONENT_TYPE_MESH, GEO_COMPONENT_TYPE_POINT_CLOUD, GEO_COMPONENT_TYPE_CURVE};
+
+    geometry_set.modify_geometry_sets([&](GeometrySet &geometry_set) {
+      for (const GeometryComponentType type : types) {
+        if (geometry_set.has(type)) {
+          GeometryComponent &component = geometry_set.get_component_for_write(type);
+          try_capture_field_on_geometry(component, anonymous_id.get(), domain, field);
+        }
+      }
+    });
+  }
 
   GField output_field{std::make_shared<bke::AnonymousAttributeFieldInput>(
       std::move(anonymous_id), type, params.attribute_producer_name())};
diff --git a/source/blender/nodes/geometry/nodes/node_geo_transfer_attribute.cc b/source/blender/nodes/geometry/nodes/node_geo_transfer_attribute.cc
index 3b30806d8ae..74b4c5d30c0 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_transfer_attribute.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_transfer_attribute.cc
@@ -41,9 +41,10 @@ namespace blender::nodes {
 static void geo_node_transfer_attribute_declare(NodeDeclarationBuilder &b)
 {
   b.add_input<decl::Geometry>(N_("Target"))
-      .only_realized_data()
-      .supported_type(
-          {GEO_COMPONENT_TYPE_MESH, GEO_COMPONENT_TYPE_POINT_CLOUD, GEO_COMPONENT_TYPE_CURVE});
+      .supported_type({GEO_COMPONENT_TYPE_MESH,
+                       GEO_COMPONENT_TYPE_POINT_CLOUD,
+                       GEO_COMPONENT_TYPE_CURVE,
+                       GEO_COMPONENT_TYPE_INSTANCES});
 
   b.add_input<decl::Vector>(N_("Attribute")).hide_value().supports_field();
   b.add_input<decl::Float>(N_("Attribute"), "Attribute_001").hide_value().supports_field();
@@ -593,8 +594,10 @@ static const GeometryComponent *find_target_component(const GeometrySet &geometr
 {
   /* Choose the other component based on a consistent order, rather than some more complicated
    * heuristic. This is the same order visible in the spreadsheet and used in the ray-cast node. */
-  static const Array<GeometryComponentType> supported_types = {
-      GEO_COMPONENT_TYPE_MESH, GEO_COMPONENT_TYPE_POINT_CLOUD, GEO_COMPONENT_TYPE_CURVE};
+  static const Array<GeometryComponentType> supported_types = {GEO_COMPONENT_TYPE_MESH,
+                                                               GEO_COMPONENT_TYPE_POINT_CLOUD,
+                                                               GEO_COMPONENT_TYPE_CURVE,
+                                                               GEO_COMPONENT_TYPE_INSTANCES};
   for (const GeometryComponentType src_type : supported_types) {
     if (component_is_available(geometry, src_type, domain)) {
       return geometry.get_component_for_read(src_type);
@@ -737,10 +740,6 @@ static void geo_node_transfer_attribute_exec(GeoNodeExecParams params)
     });
   };
 
-  /* Since the instances are not used, there is no point in keeping
-   * a reference to them while the field is passed around. */
-  geometry.remove(GEO_COMPONENT_TYPE_INSTANCES);
-
   GField output_field;
   switch (mapping) {
     case GEO_NODE_ATTRIBUTE_TRANSFER_NEAREST_FACE_INTERPOLATED: {