Geometry Nodes: Translate Instances Node

Adds a node that can translate instances in the transform space of
the modifier object, or the local space of their original transform.
One reason to have a special node for instances is that they always
have the existing transform, unlike mesh or point cloud points.

Differential Revision: https://developer.blender.org/D12679

release/scripts/startup/nodeitems_builtins.py

@@ -683,6 +683,7 @@ geometry_node_categories = [
         NodeItem("GeometryNodeSeparateGeometry"),
         NodeItem("GeometryNodeSetPosition"),
         NodeItem("GeometryNodeRealizeInstances"),
+        NodeItem("GeometryNodeTranslateInstances"),
     ]),
     GeometryNodeCategory("GEO_INPUT", "Input", items=geometry_input_node_items),
     GeometryNodeCategory("GEO_MATERIAL", "Material", items=geometry_material_node_items),

source/blender/blenkernel/BKE_node.h

@@ -1532,6 +1532,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_SET_POINT_RADIUS 1117
 #define GEO_NODE_INPUT_MATERIAL_INDEX 1118
 #define GEO_NODE_SET_MATERIAL_INDEX 1119
+#define GEO_NODE_TRANSLATE_INSTANCES 1120
 
 /** \} */
 

source/blender/blenkernel/intern/node.cc

@@ -5827,6 +5827,7 @@ static void registerGeometryNodes()
   register_node_type_geo_subdivision_surface();
   register_node_type_geo_switch();
   register_node_type_geo_transform();
+  register_node_type_geo_translate_instances();
   register_node_type_geo_triangulate();
   register_node_type_geo_viewer();
   register_node_type_geo_volume_to_mesh();

source/blender/nodes/CMakeLists.txt

@@ -269,6 +269,7 @@ set(SRC
   geometry/nodes/node_geo_string_to_curves.cc
   geometry/nodes/node_geo_switch.cc
   geometry/nodes/node_geo_transform.cc
+  geometry/nodes/node_geo_translate_instances.cc
   geometry/nodes/node_geo_triangulate.cc
   geometry/nodes/node_geo_viewer.cc
   geometry/nodes/node_geo_volume_to_mesh.cc

source/blender/nodes/NOD_geometry.h

@@ -148,6 +148,7 @@ void register_node_type_geo_string_to_curves(void);
 void register_node_type_geo_subdivision_surface(void);
 void register_node_type_geo_switch(void);
 void register_node_type_geo_transform(void);
+void register_node_type_geo_translate_instances(void);
 void register_node_type_geo_triangulate(void);
 void register_node_type_geo_viewer(void);
 void register_node_type_geo_volume_to_mesh(void);

source/blender/nodes/NOD_static_types.h

@@ -397,6 +397,7 @@ DefNode(GeometryNode, GEO_NODE_STRING_JOIN, 0, "STRING_JOIN", StringJoin, "Join
 DefNode(GeometryNode, GEO_NODE_STRING_TO_CURVES, def_geo_string_to_curves, "STRING_TO_CURVES", StringToCurves, "String to Curves", "")
 DefNode(GeometryNode, GEO_NODE_SWITCH, def_geo_switch, "SWITCH", Switch, "Switch", "")
 DefNode(GeometryNode, GEO_NODE_TRANSFORM, 0, "TRANSFORM", Transform, "Transform", "")
+DefNode(GeometryNode, GEO_NODE_TRANSLATE_INSTANCES, 0, "TRANSLATE_INSTANCES", TranslateInstances, "Translate Instances", "")
 DefNode(GeometryNode, GEO_NODE_TRIANGULATE, def_geo_triangulate, "TRIANGULATE", Triangulate, "Triangulate", "")
 DefNode(GeometryNode, GEO_NODE_VIEWER, 0, "VIEWER", Viewer, "Viewer", "")
 DefNode(GeometryNode, GEO_NODE_VOLUME_TO_MESH, def_geo_volume_to_mesh, "VOLUME_TO_MESH", VolumeToMesh, "Volume to Mesh", "")

source/blender/nodes/geometry/nodes/node_geo_translate_instances.cc

@@ -0,0 +1,84 @@
+/*
+ * 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 "BLI_task.hh"
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes {
+
+static void geo_node_translate_instances_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::Geometry>("Geometry");
+  b.add_input<decl::Bool>("Selection").default_value(true).hide_value().supports_field();
+  b.add_input<decl::Vector>("Translation").subtype(PROP_TRANSLATION).supports_field();
+  b.add_input<decl::Bool>("Local Space").default_value(true).supports_field();
+  b.add_output<decl::Geometry>("Geometry");
+};
+
+static void translate_instances(GeoNodeExecParams &params, InstancesComponent &instances_component)
+{
+  GeometryComponentFieldContext field_context{instances_component, ATTR_DOMAIN_POINT};
+
+  fn::FieldEvaluator selection_evaluator{field_context, instances_component.instances_amount()};
+  selection_evaluator.add(params.extract_input<Field<bool>>("Selection"));
+  selection_evaluator.evaluate();
+  const IndexMask selection = selection_evaluator.get_evaluated_as_mask(0);
+
+  fn::FieldEvaluator transforms_evaluator{field_context, &selection};
+  transforms_evaluator.add(params.extract_input<Field<float3>>("Translation"));
+  transforms_evaluator.add(params.extract_input<Field<bool>>("Local Space"));
+  transforms_evaluator.evaluate();
+  const VArray<float3> &translations = transforms_evaluator.get_evaluated<float3>(0);
+  const VArray<bool> &local_spaces = transforms_evaluator.get_evaluated<bool>(1);
+
+  MutableSpan<float4x4> instance_transforms = instances_component.instance_transforms();
+
+  threading::parallel_for(selection.index_range(), 1024, [&](IndexRange range) {
+    for (const int i_selection : range) {
+      const int i = selection[i_selection];
+      if (local_spaces[i]) {
+        instance_transforms[i] *= float4x4::from_location(translations[i]);
+      }
+      else {
+        add_v3_v3(instance_transforms[i].values[3], translations[i]);
+      }
+    }
+  });
+}
+
+static void geo_node_translate_instances_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+  if (geometry_set.has_instances()) {
+    InstancesComponent &instances = geometry_set.get_component_for_write<InstancesComponent>();
+    translate_instances(params, instances);
+  }
+  params.set_output("Geometry", std::move(geometry_set));
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_translate_instances()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(
+      &ntype, GEO_NODE_TRANSLATE_INSTANCES, "Translate Instances", NODE_CLASS_GEOMETRY, 0);
+  ntype.geometry_node_execute = blender::nodes::geo_node_translate_instances_exec;
+  ntype.declare = blender::nodes::geo_node_translate_instances_declare;
+  nodeRegisterType(&ntype);
+}