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// Copyright (c) 2007-09 INRIA Sophia-Antipolis (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
// 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: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/next/Point_set_processing_3/include/CGAL/grid_simplify_point_set.h $
// $Id: grid_simplify_point_set.h 67117 2012-01-13 18:14:48Z lrineau $
//
// Author(s) : Nader Salman and Laurent Saboret
#ifndef CGAL_GRID_SIMPLIFY_POINT_SET_H
#define CGAL_GRID_SIMPLIFY_POINT_SET_H
#include <CGAL/property_map.h>
#include <CGAL/point_set_processing_assertions.h>
#include <iterator>
#include <set>
#include <deque>
#include <algorithm>
#include <cmath>
namespace CGAL {
// ----------------------------------------------------------------------------
// Private section
// ----------------------------------------------------------------------------
namespace internal {
/// Utility class for grid_simplify_point_set():
/// Less_epsilon_points_3 defines a 3D points order / 2 points are equal
/// iff they belong to the same cell of a grid of cell size = epsilon.
template <class Point_3, class PointPMap>
struct Less_epsilon_points_3
{
private:
double m_epsilon;
PointPMap point_pmap;
public:
Less_epsilon_points_3 (double epsilon, PointPMap p_pmap)
: m_epsilon (epsilon), point_pmap(p_pmap)
{
CGAL_point_set_processing_precondition(epsilon > 0);
}
bool operator() (const Point_3& a, const Point_3& b) const
{
typedef typename boost::property_traits<PointPMap>::value_type Point;
// Round points to multiples of m_epsilon, then compare.
Point a_n = get(point_pmap,&a),
b_n = get(point_pmap,&b);
Point rounded_a(round_epsilon(a_n.x(), m_epsilon),
round_epsilon(a_n.y(), m_epsilon),
round_epsilon(a_n.z(), m_epsilon));
Point rounded_b(round_epsilon(b_n.x(), m_epsilon),
round_epsilon(b_n.y(), m_epsilon),
round_epsilon(b_n.z(), m_epsilon));
return (rounded_a < rounded_b);
}
private:
// Round number to multiples of epsilon
static inline double round_epsilon(double value, double epsilon)
{
return std::floor(value/epsilon) * epsilon;
}
};
} /* namespace internal */
// ----------------------------------------------------------------------------
// Public section
// ----------------------------------------------------------------------------
/// Utility class for grid_simplify_point_set():
/// 3D points set which allows at most 1 point per cell
/// of a grid of cell size = epsilon.
///
/// Warning:
/// This class is a container sorted wrt points position
/// => you should not modify directly the order or the position of points.
template <class Point_3, class PointPMap>
class Epsilon_point_set_3
: public std::set<Point_3, internal::Less_epsilon_points_3<Point_3, PointPMap> >
{
private:
// superclass
typedef std::set<Point_3, internal::Less_epsilon_points_3<Point_3, PointPMap> > Base;
public:
Epsilon_point_set_3 (double epsilon, PointPMap point_pmap)
: Base( internal::Less_epsilon_points_3<Point_3, PointPMap>(epsilon, point_pmap) )
{
CGAL_point_set_processing_precondition(epsilon > 0);
}
// default copy constructor, operator =() and destructor are fine.
};
/// Merges points which belong to the same cell of a grid of cell size = epsilon.
///
/// This method modifies the order of input points so as to pack all remaining points first,
/// and returns an iterator over the first point to remove (see erase-remove idiom).
/// For this reason it should not be called on sorted containers.
///
/// @commentheading Precondition: epsilon > 0.
///
/// @commentheading Template Parameters:
/// @param ForwardIterator iterator over input points.
/// @param PointPMap is a model of boost::ReadablePropertyMap with a value_type = Point_3<Kernel>.
/// It can be omitted if ForwardIterator value_type is convertible to Point_3<Kernel>.
/// @param Kernel Geometric traits class.
/// It can be omitted and deduced automatically from PointPMap value_type.
///
/// @return iterator over the first point to remove.
// This variant requires all parameters.
template <typename ForwardIterator,
typename PointPMap,
typename Kernel>
ForwardIterator grid_simplify_point_set(
ForwardIterator first, ///< iterator over the first input point.
ForwardIterator beyond, ///< past-the-end iterator over the input points.
PointPMap point_pmap, ///< property map ForwardIterator -> Point_3
double epsilon, ///< tolerance value when merging 3D points.
const Kernel& /*kernel*/) ///< geometric traits.
{
// actual type of input points
typedef typename std::iterator_traits<ForwardIterator>::value_type Enriched_point;
CGAL_point_set_processing_precondition(epsilon > 0);
// Merges points which belong to the same cell of a grid of cell size = epsilon.
// points_to_keep[] will contain 1 point per cell; the others will be in points_to_remove[].
Epsilon_point_set_3<Enriched_point, PointPMap> points_to_keep(epsilon, point_pmap);
std::deque<Enriched_point> points_to_remove;
for (ForwardIterator it=first ; it != beyond ; it++)
{
std::pair<typename Epsilon_point_set_3<Enriched_point, PointPMap>::iterator,bool> result;
result = points_to_keep.insert(*it);
if (!result.second) // if not inserted
points_to_remove.push_back(*it);
}
// Replaces [first, beyond) range by the content of points_to_keep, then points_to_remove.
ForwardIterator first_point_to_remove =
std::copy(points_to_keep.begin(), points_to_keep.end(), first);
std::copy(points_to_remove.begin(), points_to_remove.end(), first_point_to_remove);
return first_point_to_remove;
}
/// @cond SKIP_IN_MANUAL
// This variant deduces the kernel from the iterator type.
template <typename ForwardIterator,
typename PointPMap
>
ForwardIterator
grid_simplify_point_set(
ForwardIterator first, ///< iterator over the first input point
ForwardIterator beyond, ///< past-the-end iterator
PointPMap point_pmap, ///< property map ForwardIterator -> Point_3
double epsilon) ///< tolerance value when merging 3D points
{
typedef typename boost::property_traits<PointPMap>::value_type Point;
typedef typename Kernel_traits<Point>::Kernel Kernel;
return grid_simplify_point_set(
first,beyond,
point_pmap,
epsilon,
Kernel());
}
/// @endcond
/// @cond SKIP_IN_MANUAL
// This variant creates a default point property map = Dereference_property_map.
template <typename ForwardIterator
>
ForwardIterator
grid_simplify_point_set(
ForwardIterator first, ///< iterator over the first input point
ForwardIterator beyond, ///< past-the-end iterator
double epsilon) ///< tolerance value when merging 3D points
{
return grid_simplify_point_set(
first,beyond,
make_dereference_property_map(first),
epsilon);
}
/// @endcond
} //namespace CGAL
#endif // CGAL_GRID_SIMPLIFY_POINT_SET_H
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