mirror of https://github.com/CGAL/cgal
103 lines
2.9 KiB
C++
103 lines
2.9 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 : include/CGAL/Triangulation_utils_3.h
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// revision : $Revision$
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// author(s) : Monique Teillaud <Monique.Teillaud@sophia.inria.fr>
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//
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// coordinator : INRIA Sophia Antipolis (<Mariette.Yvinec@sophia.inria.fr>)
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//
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// ============================================================================
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#ifndef CGAL_TRIANGULATION_UTILS_3_H
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#define CGAL_TRIANGULATION_UTILS_3_H
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#include <CGAL/basic.h>
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#include <CGAL/triangulation_assertions.h>
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#include <CGAL/Triangulation_short_names_3.h>
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#include <CGAL/Triangulation_utils_2.h>
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CGAL_BEGIN_NAMESPACE
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// We use the following template class in order to avoid having a static data
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// member of a non-template class which would require src/Triangulation_3.C .
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template < class T = void >
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struct Triangulation_utils_base_3
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{
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static const char tab_next_around_edge[4][4];
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static unsigned int random_value, count, val;
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};
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template < class T >
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const char Triangulation_utils_base_3<T>::tab_next_around_edge[4][4] = {
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{5, 2, 3, 1},
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{3, 5, 0, 2},
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{1, 3, 5, 0},
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{2, 0, 1, 5} };
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template < class T >
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unsigned int Triangulation_utils_base_3<T>::random_value = 0;
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template < class T >
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unsigned int Triangulation_utils_base_3<T>::count = 0;
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template < class T >
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unsigned int Triangulation_utils_base_3<T>::val;
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// We derive from Triangulation_cw_ccw_2 because we still use cw() and ccw()
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// in the 2D part of the code. Ideally, this should go away when we re-use
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// T2D entirely.
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struct Triangulation_utils_3
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: public Triangulation_cw_ccw_2,
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public Triangulation_utils_base_3<>
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{
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static int next_around_edge(const int i, const int j)
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{
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// index of the next cell when turning around the
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// oriented edge vertex(i) vertex(j) in 3d
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CGAL_triangulation_precondition( ( i >= 0 && i < 4 ) &&
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( j >= 0 && j < 4 ) &&
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( i != j ) );
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return tab_next_around_edge[i][j];
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}
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// rand_4() outputs pseudo random unsigned ints < 4.
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// We compute random 16 bit values, that we slice/shift to make it faster.
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static unsigned int rand_4()
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{
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if (count==0)
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{
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count = 16;
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random_value = (421 * random_value + 2073) % 32749;
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val = random_value;
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}
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count--;
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unsigned int ret = val & 3;
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val = val >> 1;
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return ret;
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}
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static unsigned int rand_3()
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{
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unsigned int i = rand_4();
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return i==3 ? 0 : i;
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}
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};
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CGAL_END_NAMESPACE
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#endif // CGAL_TRIANGULATION_UTILS_3_H
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