//----------------------------------------------------------------------------
//  EgalTech 2013-2013
//----------------------------------------------------------------------------
// File : CurveAux.cpp      Data : 22.11.13          Versione : 1.3a1
// Contenuto : Implementazione di alcune funzioni di utilità per le curve.
//
//
//
// Modifiche : 22.11.13 DS Creazione modulo.
//
//
//----------------------------------------------------------------------------

//--------------------------- Include ----------------------------------------
#include "stdafx.h"
#include "CurveAux.h"


//----------------------------------------------------------------------------
bool
IsClosed( const ICurve& crvC)
{
   Point3d ptStart ;
   Point3d ptEnd ;


   return ( crvC.GetStartPoint( ptStart)  &&  crvC.GetEndPoint( ptEnd)  &&   AreSamePointNear( ptStart, ptEnd)) ;
}

//----------------------------------------------------------------------------
bool
GetPoint( const ICurve& crvC, double dU, Point3d& ptPos)
{
   Vector3d vtDer1 ;
   Vector3d vtDer2 ;


   return crvC.GetPointD1D2( dU, ptPos, vtDer1, vtDer2) ;
}

//----------------------------------------------------------------------------
bool
GetPointTang( const ICurve& crvC, double dU, Point3d& ptPos, Vector3d& vtTang)
{
   Vector3d vtDer2 ;


   if ( ! crvC.GetPointD1D2( dU, ptPos, vtTang, vtDer2))
      return false ;
   return ( vtTang.Normalize()) ;
}

//----------------------------------------------------------------------------
bool
GetPointTangNormCurv( const ICurve& crvC, double dU, Point3d& ptPos, Vector3d& vtT, Vector3d& vtN, double& dCurv)
{
   double   dLenSqD1 ;
   Vector3d vtDer2 ;


   if ( ! crvC.GetPointD1D2( dU, ptPos, vtT, vtDer2))
      return false ;
  // se esiste la derivata prima non nulla
   dLenSqD1 = vtT.LenSq() ;
   if ( vtT.Normalize()) {
     // del vettore deriv2^ tengo la sola componente perpendicolare al vettore tangente
      vtN = vtDer2 - ( vtDer2 * vtT) * vtT ;
      if ( vtN.Normalize())
         dCurv = ( vtT ^ vtDer2).Len() / dLenSqD1 ;
      else
         dCurv = 0 ;
   }
   else {
     // se esiste derivata seconda non nulla, definisce la tangente
      if ( vtDer2.Normalize())
         vtT = vtDer2 ;
      vtN.Set( 0, 0, 0) ;
      dCurv = 0 ;
   }    

   return true ;
}