OCCT

// Copyright (c) 1995-1999 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 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.

//============================================ IntAna2d_AnaIntersection_6.cxx
//============================================================================

#include <gp_Circ2d.hxx>
#include <gp_Elips2d.hxx>
#include <IntAna2d_AnaIntersection.hxx>
#include <IntAna2d_Conic.hxx>
#include <IntAna2d_IntPoint.hxx>
#include <IntAna2d_Outils.hxx>
#include <StdFail_NotDone.hxx>

void IntAna2d_AnaIntersection::Perform(const gp_Elips2d& Elips, const IntAna2d_Conic& Conic)
{
  bool   EIsDirect = Elips.IsDirect();
  double A, B, C, D, E, F;
  double pcte, ps, pc, p2sc, pcc, pss;
  double minor_radius = Elips.MinorRadius();
  double major_radius = Elips.MajorRadius();
  int    i;
  double tx, ty, S;

  done = false;
  nbp  = 0;
  para = false;
  iden = false;
  empt = false;

  gp_Ax2d Axe_rep(Elips.XAxis());

  Conic.Coefficients(A, B, C, D, E, F);
  Conic.NewCoefficients(A, B, C, D, E, F, Axe_rep);

  // Parameter: a with x=MajorRadius*cos(a) and y=MinorRadius*sin(a)

  pss  = B * minor_radius * minor_radius;       // SIN ^2
  pcc  = A * major_radius * major_radius - pss; // COS ^2
  p2sc = C * major_radius * minor_radius;       // 2 SIN COS
  pc   = 2.0 * D * major_radius;                // COS
  ps   = 2.0 * E * minor_radius;                // SIN
  pcte = F + pss;                               // 1

  math_TrigonometricFunctionRoots Sol(pcc, p2sc, pc, ps, pcte, 0.0, 2.0 * M_PI);

  if (!Sol.IsDone())
  {
    done = false;
    return;
  }
  else
  {
    if (Sol.InfiniteRoots())
    {
      iden = true;
      done = true;
      return;
    }
    nbp = Sol.NbSolutions();
    for (i = 1; i <= nbp; i++)
    {
      S  = Sol.Value(i);
      tx = major_radius * std::cos(S);
      ty = minor_radius * std::sin(S);
      Coord_Ancien_Repere(tx, ty, Axe_rep);
      if (!EIsDirect)
      {
        S = M_PI + M_PI - S;
      }
      lpnt[i - 1].SetValue(tx, ty, S);
    }
    Traitement_Points_Confondus(nbp, lpnt);
  }
  done = true;
}