Geometry Nodes: Points to Volume Fields Update

This update of the Points to Volume node allows a field to populate the
radius input of the node and removes the implicit realization of
instances.

Differential Revision: https://developer.blender.org/D12531

1 files changed, 272 insertions, 0 deletions

diff --git a/source/blender/nodes/geometry/nodes/node_geo_points_to_volume.cc b/source/blender/nodes/geometry/nodes/node_geo_points_to_volume.cc
new file mode 100644
index 00000000000..4a51d485b85
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_points_to_volume.cc
@@ -0,0 +1,272 @@
+/*
+ * 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"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+namespace blender::nodes {
+
+static void geo_node_points_to_volume_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::Geometry>("Geometry");
+  b.add_input<decl::Float>("Density").default_value(1.0f).min(0.0f);
+  b.add_input<decl::Float>("Voxel Size").default_value(0.3f).min(0.01f).subtype(PROP_DISTANCE);
+  b.add_input<decl::Float>("Voxel Amount").default_value(64.0f).min(0.0f);
+  b.add_input<decl::Float>("Radius")
+      .default_value(0.5f)
+      .min(0.0f)
+      .subtype(PROP_DISTANCE)
+      .supports_field();
+  b.add_output<decl::Geometry>("Geometry");
+}
+
+static void geo_node_points_to_volume_layout(uiLayout *layout,
+                                             bContext *UNUSED(C),
+                                             PointerRNA *ptr)
+{
+  uiLayoutSetPropSep(layout, true);
+  uiLayoutSetPropDecorate(layout, false);
+  uiItemR(layout, ptr, "resolution_mode", 0, IFACE_("Resolution"), ICON_NONE);
+}
+
+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;
+  node->storage = data;
+}
+
+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);
+}
+
+#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(GeoNodeExecParams &params,
+                                             const GeometryComponent &component,
+                                             Vector<float3> &r_positions,
+                                             Vector<float> &r_radii)
+{
+  GVArray_Typed<float3> positions = component.attribute_get_for_read<float3>(
+      "position", ATTR_DOMAIN_POINT, {0, 0, 0});
+
+  Field<float> radius_field = params.get_input<Field<float>>("Radius");
+  GeometryComponentFieldContext field_context{component, ATTR_DOMAIN_POINT};
+  const int domain_size = component.attribute_domain_size(ATTR_DOMAIN_POINT);
+
+  r_positions.resize(r_positions.size() + domain_size);
+  positions->materialize(r_positions.as_mutable_span().take_back(domain_size));
+
+  r_radii.resize(r_radii.size() + domain_size);
+  fn::FieldEvaluator evaluator{field_context, domain_size};
+  evaluator.add_with_destination(radius_field, r_radii.as_mutable_span().take_back(domain_size));
+  evaluator.evaluate();
+}
+
+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(GeoNodeExecParams &params,
+                                                    GeometrySet &r_geometry_set)
+{
+  Vector<float3> positions;
+  Vector<float> radii;
+
+  if (r_geometry_set.has<MeshComponent>()) {
+    gather_point_data_from_component(
+        params, *r_geometry_set.get_component_for_read<MeshComponent>(), positions, radii);
+  }
+  if (r_geometry_set.has<PointCloudComponent>()) {
+    gather_point_data_from_component(
+        params, *r_geometry_set.get_component_for_read<PointCloudComponent>(), positions, radii);
+  }
+  if (r_geometry_set.has<CurveComponent>()) {
+    gather_point_data_from_component(
+        params, *r_geometry_set.get_component_for_read<CurveComponent>(), 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);
+  r_geometry_set.keep_only({GEO_COMPONENT_TYPE_VOLUME, GEO_COMPONENT_TYPE_INSTANCES});
+  r_geometry_set.replace_volume(volume);
+}
+#endif
+
+static void geo_node_points_to_volume_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+
+  geometry_set.modify_geometry_sets([&](GeometrySet &geometry_set) {
+#ifdef WITH_OPENVDB
+    initialize_volume_component_from_points(params, geometry_set);
+#endif
+  });
+
+  params.set_output("Geometry", std::move(geometry_set));
+}
+
+}  // 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_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.declare = blender::nodes::geo_node_points_to_volume_declare;
+  ntype.geometry_node_execute = blender::nodes::geo_node_points_to_volume_exec;
+  ntype.draw_buttons = blender::nodes::geo_node_points_to_volume_layout;
+  nodeRegisterType(&ntype);
+}