Geometry Nodes: new Points to Volume node

This implements a new geometry node based on T84606.
It is the first node that generates a `VolumeComponent`.

Differential Revision: https://developer.blender.org/D10169

release/scripts/startup/nodeitems_builtins.py

@@ -521,6 +521,9 @@ geometry_node_categories = [
         NodeItem("GeometryNodeRotatePoints"),
         NodeItem("GeometryNodeAlignRotationToVector"),
     ]),
+    GeometryNodeCategory("GEO_VOLUME", "Volume", items=[
+        NodeItem("GeometryNodePointsToVolume"),
+    ]),
     GeometryNodeCategory("GEO_UTILITIES", "Utilities", items=[
         NodeItem("ShaderNodeMapRange"),
         NodeItem("ShaderNodeClamp"),

source/blender/blenkernel/BKE_node.h

@@ -1362,6 +1362,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_POINT_TRANSLATE 1019
 #define GEO_NODE_POINT_SCALE 1020
 #define GEO_NODE_ATTRIBUTE_SAMPLE_TEXTURE 1021
+#define GEO_NODE_POINTS_TO_VOLUME 1022
 
 /** \} */
 

source/blender/blenkernel/intern/node.c

@@ -4750,6 +4750,7 @@ static void registerGeometryNodes(void)
   register_node_type_geo_point_rotate();
   register_node_type_geo_align_rotation_to_vector();
   register_node_type_geo_sample_texture();
+  register_node_type_geo_points_to_volume();
 }
 
 static void registerFunctionNodes(void)

source/blender/editors/space_node/drawnode.c

@@ -3297,6 +3297,16 @@ static void node_geometry_buts_attribute_sample_texture(uiLayout *layout,
   uiTemplateID(layout, C, ptr, "texture", "texture.new", NULL, NULL, 0, ICON_NONE, NULL);
 }
 
+static void node_geometry_buts_points_to_volume(uiLayout *layout,
+                                                bContext *UNUSED(C),
+                                                PointerRNA *ptr)
+{
+  uiLayoutSetPropSep(layout, true);
+  uiLayoutSetPropDecorate(layout, false);
+  uiItemR(layout, ptr, "resolution_mode", DEFAULT_FLAGS, IFACE_("Resolution"), ICON_NONE);
+  uiItemR(layout, ptr, "input_type_radius", DEFAULT_FLAGS, IFACE_("Radius"), ICON_NONE);
+}
+
 static void node_geometry_set_butfunc(bNodeType *ntype)
 {
   switch (ntype->type) {
@@ -3354,6 +3364,9 @@ static void node_geometry_set_butfunc(bNodeType *ntype)
     case GEO_NODE_ATTRIBUTE_SAMPLE_TEXTURE:
       ntype->draw_buttons = node_geometry_buts_attribute_sample_texture;
       break;
+    case GEO_NODE_POINTS_TO_VOLUME:
+      ntype->draw_buttons = node_geometry_buts_points_to_volume;
+      break;
   }
 }
 

source/blender/makesdna/DNA_node_types.h

@@ -1183,6 +1183,15 @@ typedef struct NodeGeometryPointInstance {
   char _pad[6];
 } NodeGeometryPointInstance;
 
+typedef struct NodeGeometryPointsToVolume {
+  /* GeometryNodePointsToVolumeResolutionMode */
+  uint8_t resolution_mode;
+  /* GeometryNodeAttributeInputMode */
+  uint8_t input_type_radius;
+
+  char _pad[6];
+} NodeGeometryPointsToVolume;
+
 /* script node mode */
 #define NODE_SCRIPT_INTERNAL 0
 #define NODE_SCRIPT_EXTERNAL 1
@@ -1633,6 +1642,11 @@ typedef enum GeometryNodeTransformSpace {
   GEO_NODE_TRANSFORM_SPACE_RELATIVE = 1,
 } GeometryNodeTransformSpace;
 
+typedef enum GeometryNodePointsToVolumeResolutionMode {
+  GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_AMOUNT = 0,
+  GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_SIZE = 1,
+} GeometryNodePointsToVolumeResolutionMode;
+
 #ifdef __cplusplus
 }
 #endif

source/blender/makesrna/intern/rna_nodetree.c

@@ -8889,6 +8889,37 @@ static void def_geo_object_info(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
 }
 
+static void def_geo_points_to_volume(StructRNA *srna)
+{
+  PropertyRNA *prop;
+
+  static EnumPropertyItem resolution_mode_items[] = {
+      {GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_AMOUNT,
+       "VOXEL_AMOUNT",
+       0,
+       "Amount",
+       "Specify the approximate number of voxels along the diagonal"},
+      {GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_SIZE,
+       "VOXEL_SIZE",
+       0,
+       "Size",
+       "Specify the voxel side length"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  RNA_def_struct_sdna_from(srna, "NodeGeometryPointsToVolume", "storage");
+
+  prop = RNA_def_property(srna, "resolution_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, resolution_mode_items);
+  RNA_def_property_ui_text(prop, "Resolution Mode", "How the voxel size is specified");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+
+  prop = RNA_def_property(srna, "input_type_radius", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, rna_node_geometry_attribute_input_type_items_float);
+  RNA_def_property_ui_text(prop, "Radius Input Type", "");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+}
+
 /* -------------------------------------------------------------------------- */
 
 static void rna_def_shader_node(BlenderRNA *brna)

source/blender/nodes/CMakeLists.txt

@@ -160,6 +160,7 @@ set(SRC
   geometry/nodes/node_geo_point_scale.cc
   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_subdivision_surface.cc
   geometry/nodes/node_geo_transform.cc
   geometry/nodes/node_geo_triangulate.cc

source/blender/nodes/NOD_geometry.h

@@ -48,6 +48,7 @@ void register_node_type_geo_attribute_color_ramp(void);
 void register_node_type_geo_point_rotate(void);
 void register_node_type_geo_align_rotation_to_vector(void);
 void register_node_type_geo_sample_texture(void);
+void register_node_type_geo_points_to_volume(void);
 
 #ifdef __cplusplus
 }

source/blender/nodes/NOD_static_types.h

@@ -290,6 +290,7 @@ DefNode(GeometryNode, GEO_NODE_ALIGN_ROTATION_TO_VECTOR, def_geo_align_rotation_
 DefNode(GeometryNode, GEO_NODE_POINT_SCALE, def_geo_point_scale, "POINT_SCALE", PointScale, "Point Scale", "")
 DefNode(GeometryNode, GEO_NODE_POINT_TRANSLATE, def_geo_point_translate, "POINT_TRANSLATE", PointTranslate, "Point Translate", "")
 DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_SAMPLE_TEXTURE, def_geo_attribute_sample_texture, "ATTRIBUTE_SAMPLE_TEXTURE", AttributeSampleTexture, "Attribute Sample Texture", "")
+DefNode(GeometryNode, GEO_NODE_POINTS_TO_VOLUME, def_geo_points_to_volume, "POINTS_TO_VOLUME", PointsToVolume, "Points to Volume", "")
 
 /* undefine macros */
 #undef DefNode

source/blender/nodes/geometry/nodes/node_geo_points_to_volume.cc

@@ -0,0 +1,259 @@
+/*
+ * 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.
+ */
+
+#ifdef WITH_OPENVDB
+#  include <openvdb/openvdb.h>
+#  include <openvdb/tools/LevelSetUtil.h>
+#  include <openvdb/tools/ParticlesToLevelSet.h>
+#endif
+
+#include "node_geometry_util.hh"
+
+#include "BKE_lib_id.h"
+#include "BKE_volume.h"
+
+static bNodeSocketTemplate geo_node_points_to_volume_in[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {SOCK_FLOAT, N_("Density"), 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, FLT_MAX},
+    {SOCK_FLOAT, N_("Voxel Size"), 0.3f, 0.0f, 0.0f, 0.0f, 0.01f, FLT_MAX},
+    {SOCK_FLOAT, N_("Voxel Amount"), 64.0f, 0.0f, 0.0f, 0.0f, 0.0f, FLT_MAX},
+    {SOCK_STRING, N_("Radius")},
+    {SOCK_FLOAT, N_("Radius"), 0.5f, 0.0f, 0.0f, 0.0f, 0.0f, FLT_MAX},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_point_translate_out[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+#ifdef WITH_OPENVDB
+namespace {
+/* Implements the interface required by #openvdb::tools::ParticlesToLevelSet. */
+struct ParticleList {
+  using PosType = openvdb::Vec3R;
+
+  Span<float3> positions;
+  Span<float> radii;
+
+  size_t size() const
+  {
+    return (size_t)positions.size();
+  }
+
+  void getPos(size_t n, openvdb::Vec3R &xyz) const
+  {
+    xyz = &positions[n].x;
+  }
+
+  void getPosRad(size_t n, openvdb::Vec3R &xyz, openvdb::Real &radius) const
+  {
+    xyz = &positions[n].x;
+    radius = radii[n];
+  }
+};
+}  // namespace
+
+static openvdb::FloatGrid::Ptr generate_volume_from_points(const Span<float3> positions,
+                                                           const Span<float> radii,
+                                                           const float density)
+{
+  /* Create a new grid that will be filled. #ParticlesToLevelSet requires the background value to
+   * be positive. It will be set to zero later on. */
+  openvdb::FloatGrid::Ptr new_grid = openvdb::FloatGrid::create(1.0f);
+
+  /* Create a narrow-band level set grid based on the positions and radii. */
+  openvdb::tools::ParticlesToLevelSet op{*new_grid};
+  /* Don't ignore particles based on their radius. */
+  op.setRmin(0.0f);
+  op.setRmax(FLT_MAX);
+  ParticleList particles{positions, radii};
+  op.rasterizeSpheres(particles);
+  op.finalize();
+
+  /* Convert the level set to a fog volume. This also sets the background value to zero. Inside the
+   * fog there will be a density of 1. */
+  openvdb::tools::sdfToFogVolume(*new_grid);
+
+  /* Take the desired density into account. */
+  openvdb::tools::foreach (new_grid->beginValueOn(),
+                           [&](const openvdb::FloatGrid::ValueOnIter &iter) {
+                             iter.modifyValue([&](float &value) { value *= density; });
+                           });
+  return new_grid;
+}
+
+static float compute_voxel_size(const GeoNodeExecParams &params,
+                                Span<float3> positions,
+                                const float radius)
+{
+  const NodeGeometryPointsToVolume &storage =
+      *(const NodeGeometryPointsToVolume *)params.node().storage;
+
+  if (storage.resolution_mode == GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_SIZE) {
+    return params.get_input<float>("Voxel Size");
+  }
+
+  if (positions.is_empty()) {
+    return 0.0f;
+  }
+
+  float3 min, max;
+  INIT_MINMAX(min, max);
+  minmax_v3v3_v3_array(min, max, (float(*)[3])positions.data(), positions.size());
+
+  const float voxel_amount = params.get_input<float>("Voxel Amount");
+  if (voxel_amount <= 1) {
+    return 0.0f;
+  }
+
+  /* The voxel size adapts to the final size of the volume. */
+  const float diagonal = float3::distance(min, max);
+  const float extended_diagonal = diagonal + 2.0f * radius;
+  const float voxel_size = extended_diagonal / voxel_amount;
+  return voxel_size;
+}
+
+static void gather_point_data_from_component(const GeoNodeExecParams &params,
+                                             const GeometryComponent &component,
+                                             Vector<float3> &r_positions,
+                                             Vector<float> &r_radii)
+{
+  Float3ReadAttribute positions = component.attribute_get_for_read<float3>(
+      "position", ATTR_DOMAIN_POINT, {0, 0, 0});
+  FloatReadAttribute radii = params.get_input_attribute<float>(
+      "Radius", component, ATTR_DOMAIN_POINT, 0.0f);
+
+  r_positions.extend(positions.get_span());
+  r_radii.extend(radii.get_span());
+}
+
+static void convert_to_grid_index_space(const float voxel_size,
+                                        MutableSpan<float3> positions,
+                                        MutableSpan<float> radii)
+{
+  const float voxel_size_inv = 1.0f / voxel_size;
+  for (const int i : positions.index_range()) {
+    positions[i] *= voxel_size_inv;
+    /* Better align generated grid with source points. */
+    positions[i] -= float3(0.5f);
+    radii[i] *= voxel_size_inv;
+  }
+}
+
+static void initialize_volume_component_from_points(const GeometrySet &geometry_set_in,
+                                                    GeometrySet &geometry_set_out,
+                                                    const GeoNodeExecParams &params)
+{
+  Vector<float3> positions;
+  Vector<float> radii;
+
+  if (geometry_set_in.has<MeshComponent>()) {
+    gather_point_data_from_component(
+        params, *geometry_set_in.get_component_for_read<MeshComponent>(), positions, radii);
+  }
+  if (geometry_set_in.has<PointCloudComponent>()) {
+    gather_point_data_from_component(
+        params, *geometry_set_in.get_component_for_read<PointCloudComponent>(), positions, radii);
+  }
+
+  const float max_radius = *std::max_element(radii.begin(), radii.end());
+  const float voxel_size = compute_voxel_size(params, positions, max_radius);
+  if (voxel_size == 0.0f || positions.is_empty()) {
+    return;
+  }
+
+  Volume *volume = (Volume *)BKE_id_new_nomain(ID_VO, nullptr);
+  BKE_volume_init_grids(volume);
+
+  VolumeGrid *c_density_grid = BKE_volume_grid_add(volume, "density", VOLUME_GRID_FLOAT);
+  openvdb::FloatGrid::Ptr density_grid = openvdb::gridPtrCast<openvdb::FloatGrid>(
+      BKE_volume_grid_openvdb_for_write(volume, c_density_grid, false));
+
+  const float density = params.get_input<float>("Density");
+  convert_to_grid_index_space(voxel_size, positions, radii);
+  openvdb::FloatGrid::Ptr new_grid = generate_volume_from_points(positions, radii, density);
+  /* This merge is cheap, because the #density_grid is empty. */
+  density_grid->merge(*new_grid);
+  density_grid->transform().postScale(voxel_size);
+
+  VolumeComponent &volume_component = geometry_set_out.get_component_for_write<VolumeComponent>();
+  volume_component.replace(volume);
+}
+#endif
+
+static void geo_node_points_to_volume_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set_in = params.extract_input<GeometrySet>("Geometry");
+  GeometrySet geometry_set_out;
+
+#ifdef WITH_OPENVDB
+  initialize_volume_component_from_points(geometry_set_in, geometry_set_out, params);
+#endif
+
+  params.set_output("Geometry", std::move(geometry_set_out));
+}
+
+static void geo_node_points_to_volume_init(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  NodeGeometryPointsToVolume *data = (NodeGeometryPointsToVolume *)MEM_callocN(
+      sizeof(NodeGeometryPointsToVolume), __func__);
+  data->resolution_mode = GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_AMOUNT;
+  data->input_type_radius = GEO_NODE_ATTRIBUTE_INPUT_FLOAT;
+  node->storage = data;
+
+  bNodeSocket *radius_attribute_socket = nodeFindSocket(node, SOCK_IN, "Radius");
+  bNodeSocketValueString *radius_attribute_socket_value =
+      (bNodeSocketValueString *)radius_attribute_socket->default_value;
+  STRNCPY(radius_attribute_socket_value->value, "radius");
+}
+
+static void geo_node_points_to_volume_update(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  NodeGeometryPointsToVolume *data = (NodeGeometryPointsToVolume *)node->storage;
+  bNodeSocket *voxel_size_socket = nodeFindSocket(node, SOCK_IN, "Voxel Size");
+  bNodeSocket *voxel_amount_socket = nodeFindSocket(node, SOCK_IN, "Voxel Amount");
+  nodeSetSocketAvailability(voxel_amount_socket,
+                            data->resolution_mode ==
+                                GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_AMOUNT);
+  nodeSetSocketAvailability(
+      voxel_size_socket, data->resolution_mode == GEO_NODE_POINTS_TO_VOLUME_RESOLUTION_MODE_SIZE);
+
+  update_attribute_input_socket_availabilities(
+      *node, "Radius", (GeometryNodeAttributeInputMode)data->input_type_radius);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_points_to_volume()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(
+      &ntype, GEO_NODE_POINTS_TO_VOLUME, "Points to Volume", NODE_CLASS_GEOMETRY, 0);
+  node_type_socket_templates(&ntype, geo_node_points_to_volume_in, geo_node_point_translate_out);
+  node_type_storage(&ntype,
+                    "NodeGeometryPointsToVolume",
+                    node_free_standard_storage,
+                    node_copy_standard_storage);
+  node_type_size(&ntype, 170, 120, 700);
+  node_type_init(&ntype, blender::nodes::geo_node_points_to_volume_init);
+  node_type_update(&ntype, blender::nodes::geo_node_points_to_volume_update);
+  ntype.geometry_node_execute = blender::nodes::geo_node_points_to_volume_exec;
+  nodeRegisterType(&ntype);
+}