Geometry Nodes: new Select by Material node

This node creates a boolean face attribute that is "true" for
every face that has the given material.

Differential Revision: https://developer.blender.org/D11324

4 files changed, 100 insertions, 0 deletions

diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 8baa891df5c..7aaf28869de 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -189,6 +189,7 @@ set(SRC
   geometry/nodes/node_geo_point_separate.cc
   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_subdivide.cc
   geometry/nodes/node_geo_subdivision_surface.cc
   geometry/nodes/node_geo_switch.cc
diff --git a/source/blender/nodes/NOD_geometry.h b/source/blender/nodes/NOD_geometry.h
index 3c43b53da5a..df14fcfe5b4 100644
--- a/source/blender/nodes/NOD_geometry.h
+++ b/source/blender/nodes/NOD_geometry.h
@@ -78,6 +78,7 @@ void register_node_type_geo_point_separate(void);
 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_subdivide(void);
 void register_node_type_geo_subdivision_surface(void);
 void register_node_type_geo_switch(void);
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 19b671de49d..bfd99a2bb60 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -316,6 +316,7 @@ DefNode(GeometryNode, GEO_NODE_POINT_SCALE, def_geo_point_scale, "POINT_SCALE",
 DefNode(GeometryNode, GEO_NODE_POINT_SEPARATE, 0, "POINT_SEPARATE", PointSeparate, "Point Separate", "")
 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_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", "")
diff --git a/source/blender/nodes/geometry/nodes/node_geo_select_by_material.cc b/source/blender/nodes/geometry/nodes/node_geo_select_by_material.cc
new file mode 100644
index 00000000000..51be90d316e
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_select_by_material.cc
@@ -0,0 +1,97 @@
+/*
+ * 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"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BLI_task.hh"
+
+#include "BKE_material.h"
+
+static bNodeSocketTemplate geo_node_select_by_material_in[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {SOCK_MATERIAL, N_("Material")},
+    {SOCK_STRING, N_("Selection")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_select_by_material_out[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+static void select_mesh_by_material(const Mesh &mesh,
+                                    const Material *material,
+                                    const MutableSpan<bool> r_selection)
+{
+  BLI_assert(mesh.totpoly == r_selection.size());
+  Vector<int> material_indices;
+  for (const int i : IndexRange(mesh.totcol)) {
+    if (mesh.mat[i] == material) {
+      material_indices.append(i);
+    }
+  }
+  parallel_for(r_selection.index_range(), 1024, [&](IndexRange range) {
+    for (const int i : range) {
+      r_selection[i] = material_indices.contains(mesh.mpoly[i].mat_nr);
+    }
+  });
+}
+
+static void geo_node_select_by_material_exec(GeoNodeExecParams params)
+{
+  Material *material = params.extract_input<Material *>("Material");
+  const std::string selection_name = params.extract_input<std::string>("Selection");
+
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+  geometry_set = geometry_set_realize_instances(geometry_set);
+
+  if (geometry_set.has<MeshComponent>()) {
+    MeshComponent &mesh_component = geometry_set.get_component_for_write<MeshComponent>();
+    const Mesh *mesh = mesh_component.get_for_read();
+    if (mesh != nullptr) {
+      OutputAttribute_Typed<bool> selection =
+          mesh_component.attribute_try_get_for_output_only<bool>(selection_name, ATTR_DOMAIN_FACE);
+      if (selection) {
+        select_mesh_by_material(*mesh, material, selection.as_span());
+        selection.save();
+      }
+    }
+  }
+
+  params.set_output("Geometry", std::move(geometry_set));
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_select_by_material()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(
+      &ntype, GEO_NODE_SELECT_BY_MATERIAL, "Select by Material", NODE_CLASS_GEOMETRY, 0);
+  node_type_socket_templates(
+      &ntype, geo_node_select_by_material_in, geo_node_select_by_material_out);
+  ntype.geometry_node_execute = blender::nodes::geo_node_select_by_material_exec;
+  nodeRegisterType(&ntype);
+}