itkSimplexMeshToTriangleMeshFilter.h

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/*=========================================================================
 *
 *  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.
 *
 *=========================================================================*/
#ifndef itkSimplexMeshToTriangleMeshFilter_h
#define itkSimplexMeshToTriangleMeshFilter_h
 
#include "itkPolygonCell.h"
 
#include "itkSimplexMesh.h"
#include "itkMeshToMeshFilter.h"
#include "itkVectorContainer.h"
#include "itkAutomaticTopologyMeshSource.h"
 
namespace itk
{
template <typename TInputMesh, typename TOutputMesh>
class ITK_TEMPLATE_EXPORT SimplexMeshToTriangleMeshFilter : public MeshToMeshFilter<TInputMesh, TOutputMesh>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(SimplexMeshToTriangleMeshFilter);

  using Self = SimplexMeshToTriangleMeshFilter;

  using Superclass = MeshToMeshFilter<TInputMesh, TOutputMesh>;

  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(SimplexMeshToTriangleMeshFilter);
 
  using InputMeshType = TInputMesh;
  using InputMeshConstPointer = typename InputMeshType::ConstPointer;
  using InputPointType = typename InputMeshType::PointType;
  using InputPixelType = typename InputMeshType::PixelType;
  using InputCellTraitsType = typename InputMeshType::MeshTraits::CellTraits;
  using PointIdentifier = typename InputMeshType::PointIdentifier;
  using CellIdentifier = typename InputMeshType::CellIdentifier;
 
  using InputPointsContainer = typename InputMeshType::PointsContainer;
  using InputPointsContainerPointer = typename InputPointsContainer::Pointer;
  using InputPointsContainerIterator = typename InputPointsContainer::Iterator;
 
  using InputNeighbors = typename InputMeshType::NeighborListType;
  using InputNeighborsIterator = typename InputMeshType::NeighborListType::iterator;
 
  using AutoMeshSourceType = itk::AutomaticTopologyMeshSource<TOutputMesh>;
 
  using SimplexCellType = typename InputMeshType::CellType;
  using SimplexPolygonType = itk::PolygonCell<SimplexCellType>;
 
  // stores the center for each simplex mesh cell, key is the point id
  using PointMapType = itk::MapContainer<PointIdentifier, InputPointType>;
  using PointMapPointer = typename PointMapType::Pointer;

  class SimplexCellVisitor
  {
  public:
    SimplexCellVisitor() { m_CenterMap = PointMapType::New(); }

    virtual ~SimplexCellVisitor() = default;

    void
    Visit(CellIdentifier cellId, SimplexPolygonType * poly)
    {
      using PointIdIterator = typename SimplexPolygonType::PointIdIterator;
      PointIdIterator it = poly->PointIdsBegin();
      InputPointType  center{};
 
      InputPointType p{};
 
      while (it != poly->PointIdsEnd())
      {
        this->m_Mesh->GetPoint(*it, &p);
        center += p.GetVectorFromOrigin();
        ++it;
      }
 
      center[0] /= poly->GetNumberOfPoints();
      center[1] /= poly->GetNumberOfPoints();
      center[2] /= poly->GetNumberOfPoints();
 
      m_CenterMap->InsertElement(cellId, center);
    }
 
    PointMapPointer
    GetCenterMap()
    {
      return m_CenterMap;
    }
 
    void
    SetMesh(const InputMeshType * mesh)
    {
      this->m_Mesh = mesh;
    }
 
  protected:
    InputMeshConstPointer m_Mesh;
    PointMapPointer       m_CenterMap;
  };
 
  using SimplexVisitorInterfaceType = itk::
    CellInterfaceVisitorImplementation<InputPixelType, InputCellTraitsType, SimplexPolygonType, SimplexCellVisitor>;
 
  using SimplexVisitorInterfacePointer = typename SimplexVisitorInterfaceType::Pointer;
  using CellMultiVisitorType = typename SimplexCellType::MultiVisitor;
  using CellMultiVisitorPointer = typename CellMultiVisitorType::Pointer;
 
protected:
  SimplexMeshToTriangleMeshFilter() = default;
  ~SimplexMeshToTriangleMeshFilter() override = default;
 
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
  void
  GenerateData() override;
 
  void
  Initialize();

  void
  CreateTriangles();

  CellIdentifier
  FindCellId(CellIdentifier id1, CellIdentifier id2, CellIdentifier id3);

  PointMapPointer m_Centers{};
};
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkSimplexMeshToTriangleMeshFilter.hxx"
#endif
 
#endif //__SimplexMeshToTriangleMeshFilter_h