vtk_to_volume_mesh.h

#pragma once

#include <string>

#include "drake/geometry/proximity/volume_mesh.h"

namespace drake {
namespace geometry {
namespace internal {

/* @name Import tetrahedral volume meshes from VTK files for deformable
 geometries. These internal functions import VolumeMesh from a subset of VTK
 files (legacy, serial, ASCII, UNSTRUCTURED_GRID). They only support a limited
 number of tags and ignore the rest. The file format is described in:
 https://vtk.org/wp-content/uploads/2015/04/file-formats.pdf
 */
//@{

/* Reads VolumeMesh from VTK file.
 It looks for lines like these to describe positions of vertices and the four
 vertices of each tetrahedron.

      POINTS 4 float
      0.0 0.0 0.0
      1.0 0.0 0.0
      0.0 1.0 0.0
      0.0 0.0 1.0

      CELLS 1 5
      4 0 1 2 3

      CELL_TYPES 1
      10

 Other sections like POINT_DATA and CELL_DATA, e.g. per-vertex pressure value
 or per-tetrahedron velocity field are ignored.

 @param filename    A file name with absolute path or relative path.
 @param scale       An optional scale to coordinates.
 @return tetrahedral volume mesh

 @note Error handling from parsing the file is performed by VTK library.

 @throw  std::exception if the file does not exist or unsupported.
         std::exceptoin for non-positive scale factors.
 */
VolumeMesh<double> ReadVtkToVolumeMesh(const std::string& filename,
                                       double scale = 1.0);

//@}

}  // namespace internal
}  // namespace geometry
}  // namespace drake