OCCT

// Created on: 2019-07-05
// 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.

#include <BRepMesh_DelabellaBaseMeshAlgo.hxx>

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

#include <cstring>
#include <cstdarg>

#include "delabella.pxx"

IMPLEMENT_STANDARD_RTTIEXT(BRepMesh_DelabellaBaseMeshAlgo, BRepMesh_CustomBaseMeshAlgo)

namespace
{
//! Redirect algorithm messages to OCCT messenger.
static int logDelabella2Occ(void* theStream, const char* theFormat, ...)
{
  (void)theStream;
  char aBuffer[1024]; // should be more than enough for Delabella messages

  va_list anArgList;
  va_start(anArgList, theFormat);
  Vsprintf(aBuffer, theFormat, anArgList);
  va_end(anArgList);

  Message_Gravity aGravity = Message_Warning;
  switch ((int)theFormat[1])
  {
    case int('E'):
      aGravity = Message_Fail;
      break; // [ERR]
    case int('W'):
      aGravity = Message_Trace;
      break; // [WRN]
    case int('N'):
      aGravity = Message_Trace;
      break; // [NFO]
  }
  Message::Send(aBuffer, aGravity);
  return 0;
}
} // namespace

//=================================================================================================

BRepMesh_DelabellaBaseMeshAlgo::BRepMesh_DelabellaBaseMeshAlgo() = default;

//=================================================================================================

BRepMesh_DelabellaBaseMeshAlgo::~BRepMesh_DelabellaBaseMeshAlgo() = default;

//=================================================================================================

void BRepMesh_DelabellaBaseMeshAlgo::buildBaseTriangulation()
{
  const occ::handle<BRepMesh_DataStructureOfDelaun>& aStructure = this->getStructure();

  Bnd_B2d                          aBox;
  const int                        aNodesNb = aStructure->NbNodes();
  NCollection_LinearVector<double> aPoints;
  aPoints.Resize(2 * (aNodesNb + 4));
  for (int aNodeIt = 0; aNodeIt < aNodesNb; ++aNodeIt)
  {
    const BRepMesh_Vertex& aVertex = aStructure->GetNode(aNodeIt + 1);

    const size_t aBaseIdx = 2 * static_cast<size_t>(aNodeIt);
    aPoints[aBaseIdx + 0] = aVertex.Coord().X();
    aPoints[aBaseIdx + 1] = aVertex.Coord().Y();

    aBox.Add(gp_Pnt2d(aVertex.Coord()));
  }

  aBox.Enlarge(0.1 * (aBox.CornerMax() - aBox.CornerMin()).Modulus());
  const gp_XY aMin = aBox.CornerMin();
  const gp_XY aMax = aBox.CornerMax();

  aPoints[2 * aNodesNb + 0] = aMin.X();
  aPoints[2 * aNodesNb + 1] = aMin.Y();
  aStructure->AddNode(
    BRepMesh_Vertex(aPoints[2 * aNodesNb + 0], aPoints[2 * aNodesNb + 1], BRepMesh_Free));

  aPoints[2 * aNodesNb + 2] = aMax.X();
  aPoints[2 * aNodesNb + 3] = aMin.Y();
  aStructure->AddNode(
    BRepMesh_Vertex(aPoints[2 * aNodesNb + 2], aPoints[2 * aNodesNb + 3], BRepMesh_Free));

  aPoints[2 * aNodesNb + 4] = aMax.X();
  aPoints[2 * aNodesNb + 5] = aMax.Y();
  aStructure->AddNode(
    BRepMesh_Vertex(aPoints[2 * aNodesNb + 4], aPoints[2 * aNodesNb + 5], BRepMesh_Free));

  aPoints[2 * aNodesNb + 6] = aMin.X();
  aPoints[2 * aNodesNb + 7] = aMax.Y();
  aStructure->AddNode(
    BRepMesh_Vertex(aPoints[2 * aNodesNb + 6], aPoints[2 * aNodesNb + 7], BRepMesh_Free));

  const double aDiffX = (aMax.X() - aMin.X());
  const double aDiffY = (aMax.Y() - aMin.Y());
  for (size_t i = 0; i < aPoints.Size(); i += 2)
  {
    aPoints[i + 0] = (aPoints[i + 0] - aMin.X()) / aDiffX - 0.5;
    aPoints[i + 1] = (aPoints[i + 1] - aMin.Y()) / aDiffY - 0.5;
  }

  IDelaBella* aTriangulator = IDelaBella::Create();
  if (aTriangulator == nullptr) // should never happen
  {
    throw Standard_ProgramError("BRepMesh_DelabellaBaseMeshAlgo::buildBaseTriangulation: unable "
                                "creating a triangulation algorithm");
  }

  aTriangulator->SetErrLog(logDelabella2Occ, nullptr);
  try
  {
    const int aVerticesNb = aTriangulator->Triangulate(static_cast<int>(aPoints.Size() / 2),
                                                       &aPoints[0],
                                                       &aPoints[1],
                                                       2 * sizeof(double));

    if (aVerticesNb > 0)
    {
      const DelaBella_Triangle* aTrianglePtr = aTriangulator->GetFirstDelaunayTriangle();
      while (aTrianglePtr != nullptr)
      {
        int aNodes[3] = {aTrianglePtr->v[0]->i + 1,
                         aTrianglePtr->v[2]->i + 1,
                         aTrianglePtr->v[1]->i + 1};

        int  aEdges[3];
        bool aOrientations[3];
        for (int k = 0; k < 3; ++k)
        {
          const BRepMesh_Edge aLink(aNodes[k], aNodes[(k + 1) % 3], BRepMesh_Free);

          const int aLinkInfo = aStructure->AddLink(aLink);
          aEdges[k]           = std::abs(aLinkInfo);
          aOrientations[k]    = aLinkInfo > 0;
        }

        const BRepMesh_Triangle aTriangle(aEdges, aOrientations, BRepMesh_Free);
        aStructure->AddElement(aTriangle);

        aTrianglePtr = aTrianglePtr->next;
      }
    }

    aTriangulator->Destroy();
    aTriangulator = nullptr;
  }
  catch (Standard_Failure const& theException)
  {
    if (aTriangulator != nullptr)
    {
      aTriangulator->Destroy();
      aTriangulator = nullptr;
    }

    throw Standard_Failure(theException);
  }
  catch (...)
  {
    if (aTriangulator != nullptr)
    {
      aTriangulator->Destroy();
      aTriangulator = nullptr;
    }

    throw Standard_Failure("BRepMesh_DelabellaBaseMeshAlgo::buildBaseTriangulation: exception in "
                           "triangulation algorithm");
  }
}