node_geo_sdf_grid_offset.cc

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/* SPDX-FileCopyrightText: 2025 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "BKE_volume_grid.hh"
 
#include "node_geometry_util.hh"
 
#ifdef WITH_OPENVDB
#  include "openvdb/tools/LevelSetFilter.h"
#endif
 
namespace blender::nodes::node_geo_sdf_grid_offset_cc {
 
static void node_declare(NodeDeclarationBuilder &b)
{
  b.use_custom_socket_order();
  b.allow_any_socket_order();
  b.add_input<decl::Float>("Grid").hide_value().structure_type(StructureType::Grid);
  b.add_output<decl::Float>("Grid").structure_type(StructureType::Grid).align_with_previous();
  b.add_input<decl::Float>("Distance")
      .subtype(PROP_DISTANCE)
      .default_value(0.1f)
      .description("Object-space distance to offset the SDF surface");
}
 
static void node_geo_exec(GeoNodeExecParams params)
{
#ifdef WITH_OPENVDB
  auto grid = params.extract_input<bke::VolumeGrid<float>>("Grid");
  if (!grid) {
    params.set_default_remaining_outputs();
    return;
  }
 
  const float distance = params.extract_input<float>("Distance");
 
  bke::VolumeTreeAccessToken tree_token;
  openvdb::FloatGrid &vdb_grid = grid.grid_for_write(tree_token);
 
  try {
    openvdb::tools::LevelSetFilter<openvdb::FloatGrid> filter(vdb_grid);
    filter.offset(-distance);
  }
  catch (const openvdb::RuntimeError & /*e*/) {
    node_geo_sdf_grid_error_not_levelset(params);
    return;
  }
 
  params.set_output("Grid", std::move(grid));
#else
  node_geo_exec_with_missing_openvdb(params);
#endif
}
 
static void node_register()
{
  static blender::bke::bNodeType ntype;
  geo_node_type_base(&ntype, "GeometryNodeSDFGridOffset");
  ntype.ui_name = "SDF Grid Offset";
  ntype.ui_description =
      "Offset a signed distance field surface by a world-space distance. Dilates (positive) or "
      "erodes (negative) while maintaining the signed distance property";
  ntype.nclass = NODE_CLASS_GEOMETRY;
  ntype.declare = node_declare;
  ntype.geometry_node_execute = node_geo_exec;
  blender::bke::node_register_type(ntype);
}
NOD_REGISTER_NODE(node_register)
 
}  // namespace blender::nodes::node_geo_sdf_grid_offset_cc