cgal/Linear_cell_complex/include/CGAL/Linear_cell_complex_operati...

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3.6 KiB
C++

// Copyright (c) 2011 CNRS and LIRIS' Establishments (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
// Author(s) : Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
//
#ifndef CGAL_LINEAR_CELL_COMPLEX_OPERATIONS_H
#define CGAL_LINEAR_CELL_COMPLEX_OPERATIONS_H 1
#include <CGAL/Cell_iterators.h>
#include <CGAL/Combinatorial_map_operations.h>
#include <vector>
namespace CGAL {
/** @file Linear_cell_complex_operations.h
* Basic operators on a linear cell complex.
*/
/** Compute the normal of the given facet.
* @param amap the used linear cell complex.
* @param adart a dart incident to the facet.
* @return the normal of the facet.
*/
template <class LCC>
typename LCC::Vector compute_normal_of_cell_2
(const LCC& /*amap*/, typename LCC::Dart_const_handle adart)
{
// TODO Better approximation by using Newell's method
// Nx += (Vy - V'y) * (Vz + V'z);
// Ny += (Vz - V'z) * (Vx + V'x);
// Nz += (Vx - V'x) * (Vy + V'y);
// But problem with functor since this is not the sum of normal vectors.
typedef typename LCC::Point Point;
typedef typename LCC::Vector Vector;
typename LCC::Dart_const_handle start=adart;
Vector normal(CGAL::NULL_VECTOR);
while ( !start->is_free(0) && start->beta(0)!=adart )
start = start->beta(0);
if ( start->is_free(1) || start->beta(1)->other_extremity()==NULL )
return normal;
unsigned int nb = 0;
adart = start->beta(1);
const Point* prev = &LCC::point(start);
const Point* curr = &LCC::point(adart);
for ( ; adart!=start && adart->other_extremity()!=NULL;
adart=adart->beta(1) )
{
const Point* next = &LCC::point(adart->other_extremity());
if ( !typename LCC::Traits::Collinear_3()(*prev, *curr, *next) )
{
normal = typename LCC::Traits::Construct_sum_of_vectors()
(normal, typename LCC::Traits::Construct_normal_3()
(*prev, *curr, *next));
prev = curr;
++nb;
}
curr = next;
}
if ( nb<2 ) return normal;
return (typename LCC::Traits::Construct_scaled_vector()(normal, 1.0/nb));
// return normal / std::sqrt(normal * normal);
}
/** Compute the normal of the given vertex.
* @param amap the used linear cell complex.
* @param adart a dart incident to the vertex.
* @return the normal of the vertex.
*/
template <class LCC>
typename LCC::Vector compute_normal_of_cell_0
(const LCC& amap, typename LCC::Dart_const_handle adart)
{
typedef typename LCC::Vector Vector;
Vector normal(CGAL::NULL_VECTOR);
unsigned int nb = 0;
for ( CMap_one_dart_per_incident_cell_const_iterator<LCC,2,0>
it(amap, adart); it.cont(); ++it )
{
normal = typename LCC::Traits::Construct_sum_of_vectors()
(normal, CGAL::compute_normal_of_cell_2(amap,it));
++nb;
}
if ( nb<2 ) return normal;
return (typename LCC::Traits::Construct_scaled_vector()(normal, 1.0/nb));
}
} // namespace CGAL
#endif // CGAL_LINEAR_CELL_COMPLEX_OPERATIONS_H //
// EOF //