Geometry Nodes: Add Instance Scale Input Node

A field input node for the scale of each top-level instance transform.
The scale can be set with the "Scale Instances" node, but previously
could not be retrieved.

Differential Revision: https://developer.blender.org/D15132

release/scripts/startup/nodeitems_builtins.py

@@ -197,6 +197,7 @@ def geometry_instance_node_items(context):
     yield NodeItem("GeometryNodeTranslateInstances")
     yield NodeItemCustom(draw=lambda self, layout, context: layout.separator())
     yield NodeItem("GeometryNodeInputInstanceRotation")
+    yield NodeItem("GeometryNodeInputInstanceScale")
 
 # Custom Menu for Material Nodes.
 def geometry_material_node_items(context):

source/blender/blenkernel/BKE_node.h

@@ -1494,6 +1494,7 @@ struct TexResult;
 #define GEO_NODE_INPUT_NAMED_ATTRIBUTE 1157
 #define GEO_NODE_REMOVE_ATTRIBUTE 1158
 #define GEO_NODE_INPUT_INSTANCE_ROTATION 1159
+#define GEO_NODE_INPUT_INSTANCE_SCALE 1160
 
 /** \} */
 

source/blender/blenkernel/intern/node.cc

@@ -4765,6 +4765,7 @@ static void registerGeometryNodes()
   register_node_type_geo_input_id();
   register_node_type_geo_input_index();
   register_node_type_geo_input_instance_rotation();
+  register_node_type_geo_input_instance_scale();
   register_node_type_geo_input_material_index();
   register_node_type_geo_input_material();
   register_node_type_geo_input_mesh_edge_angle();

source/blender/nodes/NOD_geometry.h

@@ -63,6 +63,7 @@ void register_node_type_geo_input_curve_tilt(void);
 void register_node_type_geo_input_id(void);
 void register_node_type_geo_input_index(void);
 void register_node_type_geo_input_instance_rotation(void);
+void register_node_type_geo_input_instance_scale(void);
 void register_node_type_geo_input_material_index(void);
 void register_node_type_geo_input_material(void);
 void register_node_type_geo_input_mesh_edge_angle(void);

source/blender/nodes/NOD_static_types.h

@@ -319,6 +319,7 @@ DefNode(GeometryNode, GEO_NODE_INPUT_CURVE_TILT, 0, "INPUT_CURVE_TILT", InputCur
 DefNode(GeometryNode, GEO_NODE_INPUT_ID, 0, "INPUT_ID", InputID, "ID", "")
 DefNode(GeometryNode, GEO_NODE_INPUT_INDEX, 0, "INDEX", InputIndex, "Index", "")
 DefNode(GeometryNode, GEO_NODE_INPUT_INSTANCE_ROTATION, 0, "INPUT_INSTANCE_ROTATION", InputInstanceRotation, "Instance Rotation", "")
+DefNode(GeometryNode, GEO_NODE_INPUT_INSTANCE_SCALE, 0, "INPUT_INSTANCE_SCALE", InputInstanceScale, "Instance Scale", "")
 DefNode(GeometryNode, GEO_NODE_INPUT_MATERIAL_INDEX, 0, "INPUT_MATERIAL_INDEX", InputMaterialIndex, "Material Index", "")
 DefNode(GeometryNode, GEO_NODE_INPUT_MATERIAL, def_geo_input_material, "INPUT_MATERIAL", InputMaterial, "Material", "")
 DefNode(GeometryNode, GEO_NODE_INPUT_MESH_EDGE_ANGLE, 0, "MESH_EDGE_ANGLE", InputMeshEdgeAngle, "Edge Angle", "")

source/blender/nodes/geometry/CMakeLists.txt

@@ -72,6 +72,7 @@ set(SRC
   nodes/node_geo_input_id.cc
   nodes/node_geo_input_index.cc
   nodes/node_geo_input_instance_rotation.cc
+  nodes/node_geo_input_instance_scale.cc
   nodes/node_geo_input_material.cc
   nodes/node_geo_input_material_index.cc
   nodes/node_geo_input_mesh_edge_angle.cc

source/blender/nodes/geometry/nodes/node_geo_input_instance_scale.cc

@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes::node_geo_input_instance_scale_cc {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_output<decl::Vector>(N_("Scale")).field_source();
+}
+
+class VectorFieldInput final : public GeometryFieldInput {
+ public:
+  VectorFieldInput() : GeometryFieldInput(CPPType::get<float3>(), "Scale")
+  {
+  }
+
+  GVArray get_varray_for_context(const GeometryComponent &component,
+                                 const eAttrDomain domain,
+                                 IndexMask mask) const final
+  {
+    if (component.type() != GEO_COMPONENT_TYPE_INSTANCES) {
+      return {};
+    }
+
+    const InstancesComponent &instance_component = static_cast<const InstancesComponent &>(
+        component);
+
+    auto scale_fn = [&](const int i) -> float3 {
+      return instance_component.instance_transforms()[i].scale();
+    };
+
+    return VArray<float3>::ForFunc(instance_component.instances_num(), scale_fn);
+  }
+
+  uint64_t hash() const override
+  {
+    return 8346343;
+  }
+
+  bool is_equal_to(const fn::FieldNode &other) const override
+  {
+    return dynamic_cast<const VectorFieldInput *>(&other) != nullptr;
+  }
+};
+
+static void node_geo_exec(GeoNodeExecParams params)
+{
+  Field<float3> scale{std::make_shared<VectorFieldInput>()};
+  params.set_output("Scale", std::move(scale));
+}
+
+}  // namespace blender::nodes::node_geo_input_instance_scale_cc
+
+void register_node_type_geo_input_instance_scale()
+{
+  namespace file_ns = blender::nodes::node_geo_input_instance_scale_cc;
+
+  static bNodeType ntype;
+  geo_node_type_base(&ntype, GEO_NODE_INPUT_INSTANCE_SCALE, "Instance Scale", NODE_CLASS_INPUT);
+  ntype.geometry_node_execute = file_ns::node_geo_exec;
+  ntype.declare = file_ns::node_declare;
+  nodeRegisterType(&ntype);
+}