node_geo_grid_gradient.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/GridOperators.h"
#endif
 
namespace blender::nodes::node_geo_grid_gradient_cc {
 
static void node_declare(NodeDeclarationBuilder &b)
{
  b.add_input<decl::Float>("Grid").hide_value().structure_type(StructureType::Grid);
  b.add_output<decl::Vector>("Gradient").structure_type(StructureType::Grid);
}
 
static void node_geo_exec(GeoNodeExecParams params)
{
#ifdef WITH_OPENVDB
  const bke::VolumeGrid<float> grid = params.extract_input<bke::VolumeGrid<float>>("Grid");
  if (!grid) {
    params.set_default_remaining_outputs();
    return;
  }
  bke::VolumeTreeAccessToken tree_token;
  const openvdb::FloatGrid &vdb_grid = grid.grid(tree_token);
  openvdb::Vec3SGrid::Ptr gradient_vdb_grid = openvdb::tools::gradient(vdb_grid);
  params.set_output("Gradient", bke::VolumeGrid<float3>(std::move(gradient_vdb_grid)));
#else
  node_geo_exec_with_missing_openvdb(params);
#endif
}
 
static void node_register()
{
  static blender::bke::bNodeType ntype;
  geo_node_type_base(&ntype, "GeometryNodeGridGradient");
  ntype.ui_name = "Grid Gradient";
  ntype.ui_description =
      "Calculate the direction and magnitude of the change in values of a scalar grid";
  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_grid_gradient_cc