mirror of https://github.com/CGAL/cgal
133 lines
4.3 KiB
C++
133 lines
4.3 KiB
C++
// ======================================================================
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//
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// Copyright (c) 1999 The CGAL Consortium
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//
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// This software and related documentation is part of an INTERNAL release
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// of the Computational Geometry Algorithms Library (CGAL). It is not
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// intended for general use.
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//
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// ----------------------------------------------------------------------
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//
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// release :
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// release_date :
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//
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// file : orientation_predicatesH3.h
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// package : H3
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// revision : $Revision$
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// revision_date : $Date$
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// author(s) : Stefan Schirra
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//
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//
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// coordinator : MPI, Saarbruecken (<Stefan.Schirra@mpi-sb.mpg.de>)
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// ======================================================================
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#ifndef CGAL_ORIENTATION_PREDICATESH3_H
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#define CGAL_ORIENTATION_PREDICATESH3_H
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#include <CGAL/PVDH3.h>
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#include <CGAL/predicates_on_rtH2.h>
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#include <CGAL/predicates/sign_of_determinant.h>
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CGAL_BEGIN_NAMESPACE
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template < class R>
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CGAL_KERNEL_INLINE
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Orientation
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orientation( const PointH3<R>& p,
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const PointH3<R>& q,
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const PointH3<R>& r,
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const PointH3<R>& s)
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{
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// Two rows are switched, because of the homogeneous column.
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return (Orientation) sign_of_determinant4x4( p.hx(), p.hy(), p.hz(), p.hw(),
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r.hx(), r.hy(), r.hz(), r.hw(),
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q.hx(), q.hy(), q.hz(), q.hw(),
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s.hx(), s.hy(), s.hz(), s.hw());
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}
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template < class R>
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inline
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bool
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are_positive_oriented( const PointH3<R>& p,
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const PointH3<R>& q,
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const PointH3<R>& r,
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const PointH3<R>& s)
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{ return (orientation(p,q,r,s) == POSITIVE); }
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template < class R>
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inline
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bool
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are_negative_oriented( const PointH3<R>& p,
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const PointH3<R>& q,
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const PointH3<R>& r,
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const PointH3<R>& s)
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{ return (orientation(p,q,r,s) == NEGATIVE); }
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template < class R>
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inline
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bool
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coplanar( const PointH3<R>& p,
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const PointH3<R>& q,
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const PointH3<R>& r,
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const PointH3<R>& s)
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{ return (orientation(p,q,r,s) == COPLANAR); }
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template <class R>
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Orientation
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coplanar_orientation(const PointH3<R>& p,
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const PointH3<R>& q,
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const PointH3<R>& r,
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const PointH3<R>& s)
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// p,q,r,s supposed to be coplanar
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// p, q, r supposed to be non collinear
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// tests whether s is on the same side of p,q as r
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// returns :
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// COLLINEAR if pqs collinear
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// POSITIVE if pqr and pqs have the same orientation
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// NEGATIVE if pqr and pqs have opposite orientations
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{
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CGAL_kernel_precondition( coplanar( p, q, r, s));
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// p, q, r define a plane P:
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CGAL_kernel_precondition( !collinear( p, q, r));
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// compute orientation of p,q,s in this plane P:
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Orientation save;
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if ( (save = orientationH2( p.hy(), p.hz(), p.hw(),
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q.hy(), q.hz(), q.hw(),
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r.hy(), r.hz(), r.hw())) != COLLINEAR)
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{ return
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static_cast<Orientation>(
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static_cast<int>( save)
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* static_cast<int>( orientationH2( p.hy(), p.hz(), p.hw(),
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q.hy(), q.hz(), q.hw(),
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s.hy(), s.hz(), s.hw())) );
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}
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if ( (save = orientationH2( p.hx(), p.hz(), p.hw(),
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q.hx(), q.hz(), q.hw(),
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r.hx(), r.hz(), r.hw())) != COLLINEAR)
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{ return
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static_cast<Orientation>(
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static_cast<int>( save)
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* static_cast<int>( orientationH2( p.hx(), p.hz(), p.hw(),
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q.hx(), q.hz(), q.hw(),
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s.hx(), s.hz(), s.hw())) );
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}
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if ( (save = orientationH2( p.hx(), p.hy(), p.hw(),
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q.hx(), q.hy(), q.hw(),
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r.hx(), r.hy(), r.hw())) != COLLINEAR)
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{ return
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static_cast<Orientation>(
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static_cast<int>( save)
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* static_cast<int>( orientationH2( p.hx(), p.hy(), p.hw(),
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q.hx(), q.hy(), q.hw(),
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s.hx(), s.hy(), s.hw())) );
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}
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CGAL_kernel_assertion( false);
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return COLLINEAR;
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}
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CGAL_END_NAMESPACE
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#endif // CGAL_ORIENTATION_PREDICATESH3_H
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