occt/src/StepToGeom/StepToGeom_MakeBSplineCurve.pxx

// Created on: 1993-07-02
// Created by: Martine LANGLOIS
// Copyright (c) 1993-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// 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 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.

{
  Handle(StepGeom_BSplineCurveWithKnots)   BSCW;
  Handle(StepGeom_BSplineCurveWithKnotsAndRationalBSplineCurve) BSCWR;

  if (SC->IsKind(STANDARD_TYPE(StepGeom_BSplineCurveWithKnotsAndRationalBSplineCurve))) {
    BSCWR = 
      Handle(StepGeom_BSplineCurveWithKnotsAndRationalBSplineCurve)
	::DownCast(SC);
    BSCW = 
      Handle(StepGeom_BSplineCurveWithKnots)
	::DownCast(BSCWR->BSplineCurveWithKnots());
  }
  else
    BSCW = Handle(StepGeom_BSplineCurveWithKnots)::DownCast(SC);

  const Standard_Integer Deg = BSCW->Degree();
  const Standard_Integer NbPoles = BSCW->NbControlPointsList();
  const Standard_Integer NbKnots = BSCW->NbKnotMultiplicities();

  //aKnotMultiplicities = new TColStd_HArray1OfInteger(1,NbKnots);
  const Handle(TColStd_HArray1OfInteger)& aKnotMultiplicities = BSCW->KnotMultiplicities();
  
  Standard_Integer i;
  Standard_Integer aFMulDiff = 0,aLMulDiff = 0;
  TColStd_Array1OfInteger Mult(1,NbKnots);
  for (i=1; i<=NbKnots; ++i) {
    Standard_Integer aCurrentVal = aKnotMultiplicities->Value(i);
    if (aCurrentVal > Deg + 1)
    {
      if (i == 1)       aFMulDiff = aCurrentVal - Deg - 1;
      if (i == NbKnots) aLMulDiff = aCurrentVal - Deg - 1;
#ifdef DEB
      cout << "\nWrong multiplicity " << aCurrentVal <<  " on " << i 
           << " knot!" << "\nChanged to " << Deg + 1 << endl;
#endif
      aCurrentVal = Deg + 1;
    }
    Mult.SetValue(i,aCurrentVal);
  }
  
  //aControlPointsList = new StepGeom_HArray1OfCartesianPoint(1,NbPoles);
  const Handle(StepGeom_HArray1OfCartesianPoint)& aControlPointsList = BSCW->ControlPointsList();
  Standard_Integer aSumMulDiff = aFMulDiff + aLMulDiff;
  Array1OfPnt_gen Poles(1,NbPoles - aSumMulDiff);
  CartesianPoint_gen P;
  
  for (i = 1 + aFMulDiff; i<= NbPoles - aLMulDiff; ++i)
  {
    if (StepToGeom_MakeCartesianPoint_gen::Convert(aControlPointsList->Value(i),P))
      Poles.SetValue(i - aFMulDiff,P->Pnt_fonc());
    else
      return Standard_False;
  }
  
  //aKnots = new TColStd_HArray1OfReal(1,NbKnots);
  const Handle(TColStd_HArray1OfReal)& aKnots = BSCW->Knots();
  TColStd_Array1OfReal Kn(1,NbKnots);
  for (i=1; i<=NbKnots; i++) {
    Kn.SetValue(i,aKnots->Value(i));
  }
  
  // --- Does the Curve descriptor LOOKS like a periodic descriptor ? ---

  Standard_Integer SumMult = 0;
  for (i=1; i<=NbKnots; i++) {
    SumMult += aKnotMultiplicities->Value(i);
  }
  
  Standard_Boolean shouldBePeriodic;
  if (SumMult == (NbPoles + Deg + 1)) {
    shouldBePeriodic = Standard_False;
  }
  else if ((aKnotMultiplicities->Value(1) == 
	    aKnotMultiplicities->Value(NbKnots)) &&
	   ((SumMult - aKnotMultiplicities->Value(1)) == NbPoles)) {
    shouldBePeriodic = Standard_True;
  }
  else {  // --- What is that ??? ---
    shouldBePeriodic = Standard_False;
    //cout << "Strange BSpline Curve Descriptor" << endl;
  }
  
  if (SC->IsKind(STANDARD_TYPE(StepGeom_BSplineCurveWithKnotsAndRationalBSplineCurve))) {
    const Handle(TColStd_HArray1OfReal)& aWeight = BSCWR->WeightsData();
    TColStd_Array1OfReal W(1,NbPoles);
    for (i=1; i<=NbPoles; i++)
      W.SetValue(i,aWeight->Value(i));
    CC = new BSplineCurve_gen(Poles, W, Kn, Mult, Deg, shouldBePeriodic);
  }
  else
    CC = new BSplineCurve_gen(Poles, Kn, Mult, Deg, shouldBePeriodic);

  // abv 04.07.00 CAX-IF TRJ4: trj4_k1_top-md-203.stp #716 (face #581):
  // force periodicity on closed curves
  if ( SC->ClosedCurve() && CC->Degree() >1 && CC->IsClosed() ) {
    CC->SetPeriodic();
//#ifdef DEB
//    cout << "Warning: "__FILE__": Closed curve made periodic" << endl;
//#endif
  }
  return Standard_True;
}