text: // This file is part of libigl, a simple c++ geometry processing library.
  //
  // Copyright (C) 2016 Qingan Zhou <qnzhou@gmail.com>
  //
  // This Source Code Form is subject to the terms of the Mozilla Public License
  // v. 2.0. If a copy of the MPL was not distributed with this file, You can
  // obtain one at http://mozilla.org/MPL/2.0/.
  
  #include "orient2D.h"
  #include <CGAL/Exact_predicates_exact_constructions_kernel.h>
  #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
  
  template<typename Scalar>
  IGL_INLINE short igl::copyleft::cgal::orient2D(
      const Scalar *pa,
      const Scalar *pb,
      const Scalar *pc)
  {
    typedef CGAL::Exact_predicates_exact_constructions_kernel Epeck;
    typedef CGAL::Exact_predicates_inexact_constructions_kernel Epick;
    typedef typename std::conditional<std::is_same<Scalar, Epeck::FT>::value,
            Epeck, Epick>::type Kernel;
  
    switch(CGAL::orientation(
          typename Kernel::Point_2(pa[0], pa[1]),
          typename Kernel::Point_2(pb[0], pb[1]),
          typename Kernel::Point_2(pc[0], pc[1])))
    {
      case CGAL::LEFT_TURN:
        return 1;
      case CGAL::RIGHT_TURN:
        return -1;
      case CGAL::COLLINEAR:
        return 0;
      default:
        throw "Invalid orientation";
    }
  }
  
  #ifdef IGL_STATIC_LIBRARY
  // Explicit template instantiation
  // generated by autoexplicit.sh
  template short igl::copyleft::cgal::orient2D<double>(double const*, double const*, double const*);
  #ifdef WIN32
  #endif
  #endif
  