Geometry Nodes: Separate Components Node

Implementation of T86970. This node takes a geometry input with
multiple components and outputs them by component type. Meshes,
Curves, and Point Clouds support combining multiple input instances,
while volumes will only output the first volume component input until
suitable instance realization for multiple volumes is finished.

When direct geometry instancing is implemented it will be possible to
avoid realizing instances in this node.

Differential Revision: https://developer.blender.org/D11577

release/scripts/startup/nodeitems_builtins.py

@@ -514,6 +514,7 @@ geometry_node_categories = [
         NodeItem("GeometryNodeDeleteGeometry"),
         NodeItem("GeometryNodeTransform"),
         NodeItem("GeometryNodeJoinGeometry"),
+        NodeItem("GeometryNodeSeparateComponents"),
     ]),
     GeometryNodeCategory("GEO_INPUT", "Input", items=[
         NodeItem("GeometryNodeObjectInfo"),

source/blender/blenkernel/BKE_node.h

@@ -1436,6 +1436,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_CONVEX_HULL 1056
 #define GEO_NODE_CURVE_TO_POINTS 1057
 #define GEO_NODE_CURVE_REVERSE 1058
+#define GEO_NODE_SEPARATE_COMPONENTS 1059
 
 /** \} */
 

source/blender/blenkernel/intern/geometry_set_instances.cc

@@ -650,9 +650,16 @@ static void join_instance_groups_pointcloud(Span<GeometryInstanceGroup> set_grou
 static void join_instance_groups_volume(Span<GeometryInstanceGroup> set_groups,
                                         GeometrySet &result)
 {
-  /* Not yet supported. Joining volume grids with the same name requires resampling of at least
-   * one of the grids. The cell size of the resulting volume has to be determined somehow. */
-  UNUSED_VARS(set_groups, result);
+  /* Not yet supported; for now only return the first volume. Joining volume grids with the same
+   * name requires resampling of at least one of the grids. The cell size of the resulting volume
+   * has to be determined somehow. */
+  for (const GeometryInstanceGroup &set_group : set_groups) {
+    const GeometrySet &set = set_group.geometry_set;
+    if (set.has<VolumeComponent>()) {
+      result.add(*set.get_component_for_read<VolumeComponent>());
+      return;
+    }
+  }
 }
 
 static void join_instance_groups_curve(Span<GeometryInstanceGroup> set_groups, GeometrySet &result)

source/blender/blenkernel/intern/node.cc

@@ -5084,6 +5084,7 @@ static void registerGeometryNodes()
   register_node_type_geo_points_to_volume();
   register_node_type_geo_sample_texture();
   register_node_type_geo_select_by_material();
+  register_node_type_geo_separate_components();
   register_node_type_geo_subdivide();
   register_node_type_geo_subdivision_surface();
   register_node_type_geo_switch();

source/blender/nodes/CMakeLists.txt

@@ -193,6 +193,7 @@ set(SRC
   geometry/nodes/node_geo_point_translate.cc
   geometry/nodes/node_geo_points_to_volume.cc
   geometry/nodes/node_geo_select_by_material.cc
+  geometry/nodes/node_geo_separate_components.cc
   geometry/nodes/node_geo_subdivide.cc
   geometry/nodes/node_geo_subdivision_surface.cc
   geometry/nodes/node_geo_switch.cc

source/blender/nodes/NOD_geometry.h

@@ -82,6 +82,7 @@ void register_node_type_geo_point_translate(void);
 void register_node_type_geo_points_to_volume(void);
 void register_node_type_geo_sample_texture(void);
 void register_node_type_geo_select_by_material(void);
+void register_node_type_geo_separate_components(void);
 void register_node_type_geo_subdivide(void);
 void register_node_type_geo_subdivision_surface(void);
 void register_node_type_geo_switch(void);

source/blender/nodes/NOD_static_types.h

@@ -320,6 +320,7 @@ DefNode(GeometryNode, GEO_NODE_POINT_SEPARATE, 0, "POINT_SEPARATE", PointSeparat
 DefNode(GeometryNode, GEO_NODE_POINT_TRANSLATE, def_geo_point_translate, "POINT_TRANSLATE", PointTranslate, "Point Translate", "")
 DefNode(GeometryNode, GEO_NODE_POINTS_TO_VOLUME, def_geo_points_to_volume, "POINTS_TO_VOLUME", PointsToVolume, "Points to Volume", "")
 DefNode(GeometryNode, GEO_NODE_SELECT_BY_MATERIAL, 0, "SELECT_BY_MATERIAL", SelectByMaterial, "Select by Material", "")
+DefNode(GeometryNode, GEO_NODE_SEPARATE_COMPONENTS, 0, "SEPARATE_COMPONENTS", SeparateComponents, "Separate Components", "")
 DefNode(GeometryNode, GEO_NODE_SUBDIVIDE, 0, "SUBDIVIDE", Subdivide, "Subdivide", "")
 DefNode(GeometryNode, GEO_NODE_SUBDIVISION_SURFACE, 0, "SUBDIVISION_SURFACE", SubdivisionSurface, "Subdivision Surface", "")
 DefNode(GeometryNode, GEO_NODE_SWITCH, def_geo_switch, "SWITCH", Switch, "Switch", "")

source/blender/nodes/geometry/nodes/node_geo_separate_components.cc

@@ -0,0 +1,77 @@
+/*
+ * 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"
+
+static bNodeSocketTemplate geo_node_join_geometry_in[]{
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_join_geometry_out[]{
+    {SOCK_GEOMETRY, N_("Mesh")},
+    {SOCK_GEOMETRY, N_("Point Cloud")},
+    {SOCK_GEOMETRY, N_("Curve")},
+    {SOCK_GEOMETRY, N_("Volume")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+static void geo_node_separate_components_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+
+  /* Note that it will be possible to skip realizing instances here when instancing
+   * geometry directly is supported by creating corresponding geometry instances. */
+  geometry_set = bke::geometry_set_realize_instances(geometry_set);
+
+  GeometrySet meshes;
+  GeometrySet point_clouds;
+  GeometrySet volumes;
+  GeometrySet curves;
+
+  if (geometry_set.has<MeshComponent>()) {
+    meshes.add(*geometry_set.get_component_for_read<MeshComponent>());
+  }
+  if (geometry_set.has<PointCloudComponent>()) {
+    point_clouds.add(*geometry_set.get_component_for_read<PointCloudComponent>());
+  }
+  if (geometry_set.has<CurveComponent>()) {
+    curves.add(*geometry_set.get_component_for_read<CurveComponent>());
+  }
+  if (geometry_set.has<VolumeComponent>()) {
+    volumes.add(*geometry_set.get_component_for_read<VolumeComponent>());
+  }
+
+  params.set_output("Mesh", meshes);
+  params.set_output("Point Cloud", point_clouds);
+  params.set_output("Curve", curves);
+  params.set_output("Volume", volumes);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_separate_components()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(
+      &ntype, GEO_NODE_SEPARATE_COMPONENTS, "Separate Components", NODE_CLASS_GEOMETRY, 0);
+  node_type_socket_templates(&ntype, geo_node_join_geometry_in, geo_node_join_geometry_out);
+  ntype.geometry_node_execute = blender::nodes::geo_node_separate_components_exec;
+  nodeRegisterType(&ntype);
+}