SphinxExamples/src/Core/Mesh/WriteMeshToVTP/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#include "itkMesh.h"
#include "itkLineCell.h"
#include "itkVTKPolyDataWriter.h"
 
constexpr unsigned int Dimension = 3;
using MeshType = itk::Mesh<float, Dimension>;
 
MeshType::Pointer
CreateMeshWithEdges();
 
int
main()
{
 
  MeshType::Pointer mesh = CreateMeshWithEdges();
 
  using WriterType = itk::VTKPolyDataWriter<MeshType>;
  auto writer = WriterType::New();
  writer->SetInput(mesh);
  writer->SetFileName("test.vtk");
  writer->Update();
 
  return EXIT_SUCCESS;
}
 
 
MeshType::Pointer
CreateMeshWithEdges()
{
 
  auto mesh = MeshType::New();
 
  // Create points
  const MeshType::PointType p0({ -1.0, -1.0, 0 });
  const MeshType::PointType p1({ 1.0, -1.0, 0.0 });
  const MeshType::PointType p2({ 1.0, 1.0, 0.0 });
  const MeshType::PointType p3({ 1.0, 1.0, 1.0 });
 
  mesh->SetPoint(0, p0);
  mesh->SetPoint(1, p1);
  mesh->SetPoint(2, p2);
  mesh->SetPoint(3, p3);
 
  std::cout << "Points = " << mesh->GetNumberOfPoints() << std::endl;
 
  // access points
  using PointsIterator = MeshType::PointsContainer::Iterator;
 
  PointsIterator pointIterator = mesh->GetPoints()->Begin();
  PointsIterator end = mesh->GetPoints()->End();
  while (pointIterator != end)
  {
    MeshType::PointType p = pointIterator.Value(); // access the point
    std::cout << p << std::endl;                   // print the point
    ++pointIterator;                               // advance to next point
  }
 
  using CellAutoPointer = MeshType::CellType::CellAutoPointer;
  using LineType = itk::LineCell<MeshType::CellType>;
 
  CellAutoPointer line0;
  line0.TakeOwnership(new LineType);
  line0->SetPointId(0, 0); // line between points 0 and 1
  line0->SetPointId(1, 1);
  mesh->SetCell(0, line0);
 
  CellAutoPointer line1;
  line1.TakeOwnership(new LineType);
  line1->SetPointId(0, 1); // line between points 1 and 2
  line1->SetPointId(1, 2);
  mesh->SetCell(1, line1);
 
  CellAutoPointer line2;
  line2.TakeOwnership(new LineType);
  line2->SetPointId(0, 2); // line between points 2 and 3
  line2->SetPointId(1, 3);
  mesh->SetCell(2, line2);
 
  return mesh;
}