// Created on: 1993-01-20
// Created by: Didier PIFFAULT
// 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 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.

#include <Intf.hxx>

#include <gp_Pnt.hxx>
#include <gp_XYZ.hxx>

//=================================================================================================

void Intf::PlaneEquation(const gp_Pnt&  P1,
                         const gp_Pnt&  P2,
                         const gp_Pnt&  P3,
                         gp_XYZ&        NormalVector,
                         Standard_Real& PolarDistance)
{
  gp_XYZ v1              = P2.XYZ() - P1.XYZ();
  gp_XYZ v2              = P3.XYZ() - P2.XYZ();
  gp_XYZ v3              = P1.XYZ() - P3.XYZ();
  NormalVector           = (v1 ^ v2) + (v2 ^ v3) + (v3 ^ v1);
  Standard_Real aNormLen = NormalVector.Modulus();
  if (aNormLen < gp::Resolution())
  {
    PolarDistance = 0.;
  }
  else
  {
    NormalVector.Divide(aNormLen);
    PolarDistance = NormalVector * P1.XYZ();
  }
}

//=================================================================================================

Standard_Boolean Intf::Contain(const gp_Pnt& P1,
                               const gp_Pnt& P2,
                               const gp_Pnt& P3,
                               const gp_Pnt& ThePnt)
{
  gp_XYZ v1 = (P2.XYZ() - P1.XYZ()) ^ (ThePnt.XYZ() - P1.XYZ());
  gp_XYZ v2 = (P3.XYZ() - P2.XYZ()) ^ (ThePnt.XYZ() - P2.XYZ());
  gp_XYZ v3 = (P1.XYZ() - P3.XYZ()) ^ (ThePnt.XYZ() - P3.XYZ());
  if (v1 * v2 >= 0. && v2 * v3 >= 0. && v3 * v1 >= 0.)
    return Standard_True;
  else
    return Standard_False;
}