0023706: Cannot project point on curve

[occt.git] / src / LProp / LProp_FuncCurExt.gxx

// Created on: 1994-09-06
// Created by: Yves FRICAUD
// Copyright (c) 1994-1999 Matra Datavision
// Copyright (c) 1999-2012 OPEN CASCADE SAS
//
// The content of this file is subject to the Open CASCADE Technology Public
// License Version 6.5 (the "License"). You may not use the content of this file
// except in compliance with the License. Please obtain a copy of the License
// at http://www.opencascade.org and read it completely before using this file.
//
// The Initial Developer of the Original Code is Open CASCADE S.A.S., having its
// main offices at: 1, place des Freres Montgolfier, 78280 Guyancourt, France.
//
// The Original Code and all software distributed under the License is
// distributed on an "AS IS" basis, without warranty of any kind, and the
// Initial Developer hereby disclaims all such warranties, including without
// limitation, any warranties of merchantability, fitness for a particular
// purpose or non-infringement. Please see the License for the specific terms
// and conditions governing the rights and limitations under the License.


#include <gp.hxx>
#include <Precision.hxx>

//=============================================================================
//function :
// purpose :
//=============================================================================
LProp_FuncCurExt::LProp_FuncCurExt(const Curve&  C,
				   const Standard_Real Tol)
:theCurve(C)
{
  epsX  = Tol;
}

//=============================================================================
//function : Value 
// purpose : KC = (V1^V2.Z) / ||V1||^3  avec V1 tangente etV2 derivee seconde.
//           F  = d KC/ dU.
//=============================================================================
Standard_Boolean  LProp_FuncCurExt::Value (const Standard_Real  X,
					         Standard_Real& F)
{
  Pnt            P1;
  Vec            V1,V2,V3;

  Tool::D3(theCurve,X,P1,V1,V2,V3);
  Standard_Real CPV1V2 = V1.Crossed(V2);
  Standard_Real CPV1V3 = V1.Crossed(V3);
  Standard_Real V1V2   = V1.Dot(V2);
  Standard_Real V1V1   = V1.SquareMagnitude();
  Standard_Real NV1    = Sqrt(V1V1);
  Standard_Real V13    = V1V1*NV1;
  Standard_Real V15    = V13*V1V1;

  if (V15 < gp::Resolution()) {
    return Standard_False;
  }
  F = CPV1V3/V13 - 3*CPV1V2*V1V2/V15;

  return Standard_True;
}

//=============================================================================
//function : Derivative
// purpose :
//=============================================================================
Standard_Boolean LProp_FuncCurExt::Derivative(const Standard_Real  X,
					            Standard_Real& D)
{  
  Standard_Real F;
  return Values (X,F,D) ;
}

//=============================================================================
//function : Values
// purpose :
//=============================================================================
Standard_Boolean LProp_FuncCurExt::Values (const Standard_Real  X,
					         Standard_Real& F,
					         Standard_Real& D)
{
  Standard_Real F2;
  Standard_Real Dx= epsX/100.;

  if (X+Dx > Tool::LastParameter(theCurve)) {Dx = - Dx;}

  Value (X,F);
  Value (X+Dx,F2);
  D     = (F2 - F)/Dx;

  return Standard_True;
}


//=============================================================================
//function : IsMinKC
// purpose : Teste si le parametere coorespond a un minimum du rayon de courbure
//           par comparaison avec un point voisin.
//=============================================================================
Standard_Boolean LProp_FuncCurExt::IsMinKC (const Standard_Real  X) const
{
  Pnt            P1;
  Vec            V1,V2,V3;
  Standard_Real  Dx= epsX;
  Standard_Real  KC,KP;

  Tool::D3(theCurve,X,P1,V1,V2,V3);
  Standard_Real CPV1V2 = V1.Crossed(V2);
  Standard_Real V1V1   = V1.SquareMagnitude();
  Standard_Real NV1    = Sqrt(V1V1);
  Standard_Real V13    = V1V1*NV1;

  if (V13 < gp::Resolution()) {return Standard_False;}

  KC = CPV1V2/V13;

  if (X+Dx > Tool::LastParameter(theCurve)) {Dx = - Dx;}

  Tool::D3(theCurve,X+Dx,P1,V1,V2,V3);
  CPV1V2 = V1.Crossed(V2);
  V1V1   = V1.SquareMagnitude();
  NV1    = Sqrt(V1V1);
  V13    = V1V1*NV1;
   
  if (V13 < gp::Resolution()) { return Standard_False;}
  KP = CPV1V2/V13;

  if   (Abs(KC) > Abs(KP)) {return Standard_True ;}
  else                     {return Standard_False;} 

}