1 files changed, 94 insertions, 0 deletions
diff --git a/source/blender/nodes/geometry/nodes/node_geo_set_id.cc b/source/blender/nodes/geometry/nodes/node_geo_set_id.cc
new file mode 100644
index 00000000000..77d8e786501
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_set_id.cc
@@ -0,0 +1,94 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes {
+
+static void geo_node_set_id_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::Geometry>(N_("Geometry"));
+  b.add_input<decl::Bool>(N_("Selection")).default_value(true).hide_value().supports_field();
+  b.add_input<decl::Int>(N_("ID")).implicit_field();
+  b.add_output<decl::Geometry>(N_("Geometry"));
+}
+
+static void set_id_in_component(GeometryComponent &component,
+                                const Field<bool> &selection_field,
+                                const Field<int> &id_field)
+{
+  GeometryComponentFieldContext field_context{component, ATTR_DOMAIN_POINT};
+  const int domain_size = component.attribute_domain_size(ATTR_DOMAIN_POINT);
+  if (domain_size == 0) {
+    return;
+  }
+
+  fn::FieldEvaluator selection_evaluator{field_context, domain_size};
+  selection_evaluator.add(selection_field);
+  selection_evaluator.evaluate();
+  const IndexMask selection = selection_evaluator.get_evaluated_as_mask(0);
+
+  /* Since adding the ID attribute can change the result of the field evaluation (the random value
+   * node uses the index if the ID is unavailable), make sure that it isn't added before evaluating
+   * the field. However, as an optimization, use a faster code path when it already exists. */
+  fn::FieldEvaluator id_evaluator{field_context, &selection};
+  if (component.attribute_exists("id")) {
+    OutputAttribute_Typed<int> id_attribute = component.attribute_try_get_for_output_only<int>(
+        "id", ATTR_DOMAIN_POINT);
+    id_evaluator.add_with_destination(id_field, id_attribute.varray());
+    id_evaluator.evaluate();
+    id_attribute.save();
+  }
+  else {
+    id_evaluator.add(id_field);
+    id_evaluator.evaluate();
+    const VArray<int> &result_ids = id_evaluator.get_evaluated<int>(0);
+    OutputAttribute_Typed<int> id_attribute = component.attribute_try_get_for_output_only<int>(
+        "id", ATTR_DOMAIN_POINT);
+    result_ids.materialize(selection, id_attribute.as_span());
+    id_attribute.save();
+  }
+}
+
+static void geo_node_set_id_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+  Field<bool> selection_field = params.extract_input<Field<bool>>("Selection");
+  Field<int> id_field = params.extract_input<Field<int>>("ID");
+
+  for (const GeometryComponentType type : {GEO_COMPONENT_TYPE_INSTANCES,
+                                           GEO_COMPONENT_TYPE_MESH,
+                                           GEO_COMPONENT_TYPE_POINT_CLOUD,
+                                           GEO_COMPONENT_TYPE_CURVE}) {
+    if (geometry_set.has(type)) {
+      set_id_in_component(geometry_set.get_component_for_write(type), selection_field, id_field);
+    }
+  }
+
+  params.set_output("Geometry", std::move(geometry_set));
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_set_id()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(&ntype, GEO_NODE_SET_ID, "Set ID", NODE_CLASS_GEOMETRY, 0);
+  ntype.geometry_node_execute = blender::nodes::geo_node_set_id_exec;
+  ntype.declare = blender::nodes::geo_node_set_id_declare;
+  nodeRegisterType(&ntype);
+}