OCCT

// Created on: 2019-06-07
// Copyright (c) 2019 OPEN CASCADE SAS
// Created by: Oleg AGASHIN
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _BRepMesh_CustomBaseMeshAlgo_HeaderFile
#define _BRepMesh_CustomBaseMeshAlgo_HeaderFile

#include <BRepMesh_ConstrainedBaseMeshAlgo.hxx>
#include <NCollection_Shared.hxx>

#include <BRepMesh_Delaun.hxx>
#include <BRepMesh_MeshTool.hxx>

//! Class provides base functionality to build face triangulation using custom triangulation
//! algorithm. Performs generation of mesh using raw data from model.
class BRepMesh_CustomBaseMeshAlgo : public BRepMesh_ConstrainedBaseMeshAlgo
{
public:
  //! Constructor.
  BRepMesh_CustomBaseMeshAlgo() = default;

  //! Destructor.
  ~BRepMesh_CustomBaseMeshAlgo() override = default;

  DEFINE_STANDARD_RTTIEXT(BRepMesh_CustomBaseMeshAlgo, BRepMesh_ConstrainedBaseMeshAlgo)

protected:
  //! Generates mesh for the contour stored in data structure.
  void generateMesh(const Message_ProgressRange& theRange) override
  {
    const occ::handle<BRepMesh_DataStructureOfDelaun>& aStructure = this->getStructure();
    const int                                          aNodesNb   = aStructure->NbNodes();

    buildBaseTriangulation();

    std::pair<int, int> aCellsCount = this->getCellsCount(aStructure->NbNodes());
    BRepMesh_Delaun     aMesher(aStructure, aCellsCount.first, aCellsCount.second, false);

    const int  aNewNodesNb = aStructure->NbNodes();
    const bool isRemoveAux = aNewNodesNb > aNodesNb;
    if (isRemoveAux)
    {
      IMeshData::VectorOfInteger aAuxVertices(aNewNodesNb - aNodesNb);
      for (int aExtNodesIt = aNodesNb + 1; aExtNodesIt <= aNewNodesNb; ++aExtNodesIt)
      {
        aAuxVertices.Append(aExtNodesIt);
      }

      // Set aux vertices if there are some to clean up mesh correctly.
      aMesher.SetAuxVertices(aAuxVertices);
    }

    aMesher.ProcessConstraints();

    // Destruction of triangles containing aux vertices added (possibly) during base mesh
    // computation.
    if (isRemoveAux)
    {
      aMesher.RemoveAuxElements();
    }

    BRepMesh_MeshTool aCleaner(aStructure);
    aCleaner.EraseFreeLinks();

    postProcessMesh(aMesher, theRange);
  }

protected:
  //! Builds base triangulation using custom triangulation algorithm.
  Standard_EXPORT virtual void buildBaseTriangulation() = 0;
};

#endif