OpenCascade BSpline Curve

//=======================================================================//function : LocalValue//purpose  : //=======================================================================gp_Pnt Geom_BSplineCurve::LocalValue  (const Standard_Real    U,   const Standard_Integer FromK1,   const Standard_Integer ToK2)   const{  gp_Pnt P;  LocalD0(U,FromK1,ToK2,P);  return P;}//=======================================================================//function : LocalD0//purpose  : //=======================================================================void  Geom_BSplineCurve::LocalD0  (const Standard_Real    U,   const Standard_Integer FromK1,   const Standard_Integer ToK2,   gp_Pnt& P)   const{  Standard_DomainError_Raise_if (FromK1 == ToK2, "Geom_BSplineCurve::LocalValue");  Standard_Real u = U;  Standard_Integer index = 0;  BSplCLib::LocateParameter(deg, FKNOTS, U, periodic,FromK1,ToK2, index,u);  index = BSplCLib::FlatIndex(deg,index,mults->Array1(),periodic);  if (rational) {    BSplCLib::D0(u,index,deg,periodic,POLES, weights->Array1(), FKNOTS,FMULTS,P);  }  else {    BSplCLib::D0(u,index,deg,periodic,POLES, *((TColStd_Array1OfReal*) NULL), FKNOTS,FMULTS,P);  }}

 

//=======================================================================//function : LocateParameter//purpose  : Pour des noeuds plats//   pmn  28-01-97 -> On a bel est bien besoin du degree pour calculer//   la periode eventuelle//=======================================================================void BSplCLib::LocateParameter(const Standard_Integer          Degree, const Array1OfReal&    Knots, const Standard_Real             U, const Standard_Boolean          IsPeriodic, const Standard_Integer          FromK1, const Standard_Integer          ToK2, Standard_Integer&               KnotIndex, Standard_Real&                  NewU){   if (IsPeriodic)    BSplCLib::LocateParameter(Knots, U, IsPeriodic, FromK1, ToK2,      KnotIndex, NewU,      Knots(Knots.Lower() + Degree),      Knots(Knots.Upper() - Degree));  else     BSplCLib::LocateParameter(Knots, U, IsPeriodic, FromK1, ToK2,      KnotIndex, NewU,      0.,      1.);}

 

//=======================================================================//function : LocateParameter//purpose  : Claculs effectifs// pmn 28-01-97 : Ajoute les bornes de la periode en argument d'entree, car il est //                car il est imposible de les inventer a ce niveaux.//=======================================================================void BSplCLib::LocateParameter (const TColStd_Array1OfReal& Knots, const Standard_Real         U, const Standard_Boolean      IsPeriodic, const Standard_Integer      FromK1, const Standard_Integer      ToK2, Standard_Integer&           KnotIndex, Standard_Real&              NewU, const Standard_Real         UFirst, const Standard_Real         ULast){  Standard_Integer First,Last;  if (FromK1 < ToK2) {    First = FromK1;    Last  = ToK2;  }  else {    First = ToK2;    Last  = FromK1;  }  Standard_Integer Last1 = Last - 1;  NewU = U;  if (IsPeriodic) {    Standard_Real Period = ULast - UFirst;    while (NewU > ULast )      NewU  -= Period;    while (NewU < UFirst)      NewU  += Period;  }    BSplCLib::Hunt (Knots, NewU, KnotIndex);    Standard_Real Eps = Epsilon(U);  Standard_Real val;  if (Eps < 0) Eps = - Eps;  Standard_Integer KLower = Knots.Lower();  const Standard_Real *knots = &Knots(KLower);  knots -= KLower;  if ( KnotIndex < Knots.Upper()) {    val = NewU - knots[KnotIndex + 1];    if (val < 0) val = - val;    // <= pour etre coherant avec les Segment ou Eps correspond a un bit d'erreur.    if (val <= Eps) KnotIndex++;   }  if (KnotIndex < First) KnotIndex = First;  if (KnotIndex > Last1) KnotIndex = Last1;    if (KnotIndex != Last1) {    Standard_Real K1 = knots[KnotIndex];    Standard_Real K2 = knots[KnotIndex + 1];    val = K2 - K1;    if (val < 0) val = - val;    while (val <= Eps) {      KnotIndex++;      K1 = K2;      K2 = knots[KnotIndex + 1];      val = K2 - K1;      if (val < 0) val = - val;    }  }}

 

//=======================================================================//function : Hunt//purpose  : //=======================================================================void BSplCLib::Hunt (const Array1OfReal& XX,      const Standard_Real X,     Standard_Integer&   Ilc){  // replaced by simple dichotomy (RLE)  Ilc = XX.Lower();  const Standard_Real *px = &XX(Ilc);  px -= Ilc;  if (X < px[Ilc]) {    Ilc--;    return;  }  Standard_Integer Ihi = XX.Upper();  if (X > px[Ihi]) {    Ilc = Ihi + 1;    return;  }  Standard_Integer Im;  while (Ihi - Ilc != 1) {    Im = (Ihi + Ilc) >> 1;    if (X > px[Im]) Ilc = Im;    else            Ihi = Im;  }}