mirror of https://github.com/CGAL/cgal
63 lines
1.7 KiB
C++
63 lines
1.7 KiB
C++
// Copyright (c) 1999 Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
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// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
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// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; version 2.1 of the License.
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// See the file LICENSE.LGPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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//
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//
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// Author(s) : Stefan Schirra
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#ifndef CGAL_PREDICATES_ON_RTH2_H
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#define CGAL_PREDICATES_ON_RTH2_H
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CGAL_BEGIN_NAMESPACE
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template <class RT>
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CGAL_KERNEL_INLINE
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Orientation
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orientationH2( const RT& phx, const RT& phy, const RT& phw,
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const RT& qhx, const RT& qhy, const RT& qhw,
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const RT& rhx, const RT& rhy, const RT& rhw )
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{
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const RT RT0 = RT(0);
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// | A B |
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// | C D |
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RT A = phx*rhw - phw*rhx;
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RT B = phy*rhw - phw*rhy;
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RT C = qhx*rhw - qhw*rhx;
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RT D = qhy*rhw - qhw*rhy;
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RT det = A*D - B*C;
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if (det < RT0 )
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{
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return CLOCKWISE;
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}
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else
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{
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return (RT0 < det) ? COUNTERCLOCKWISE : COLLINEAR;
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}
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}
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CGAL_END_NAMESPACE
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#endif // CGAL_PREDICATES_ON_RTH2_H
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