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CGAL 4.6.1 - 2D and Surface Function Interpolation
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Functions
3D Surface Neighbors Functions
Surface Neighbor and Surface Neighbor Coordinate Computation

Given a set of sample points issued from a surface and a query point p, the functions surface_neighbors_3() compute the neighbors of p on the surface within the sample points.

If the sampling is sufficiently dense, the neighbors are provably close to the point p on the surface (cf. the manual pages and [2],[5]). They are defined to be the neighbors of p in the regular triangulation dual to the power diagram which is equivalent to the intersection of the Voronoi cell of the query point p with the tangent plane to the surface at p.

The functions surface_neighbors_certified_3() also return, in addition, a Boolean value that certifies whether or not, the Voronoi cell of p can be affected by points that lie outside the input range, i.e. outside the ball centered on p passing through the furthest sample point from p in the range [first, beyond). If the sample points are collected by a k-nearest neighbor or a range search query, this permits to verify that a large enough neighborhood has been considered.

Requirements

  1. Dt is equivalent to the class Delaunay_triangulation_3.
  2. OutputIterator::value_type is equivalent to Dt::Point_3, i.e. a point type.
  3. ITraits is equivalent to the class Voronoi_intersection_2_traits_3<K>.
See Also
CGAL::Voronoi_intersection_2_traits_3<K>
3D Surface Neighbor Coordinates Functions

Implementation

These functions compute the regular triangulation of the sample points and the point p using a traits class equivalent to Voronoi_intersection_2_traits_3<K>. They determine the neighbors of p in this triangulation. The functions which certify the result need to compute, in addition, the Voronoi vertices of the cell of p in this diagram.

Functions

template<class OutputIterator , class InputIterator , class Kernel >
OutputIterator CGAL::surface_neighbors_3 (InputIterator first, InputIterator beyond, const typename Kernel::Point_3 &p, const typename Kernel::Vector_3 &normal, OutputIterator out, const Kernel &K)
 The sample points \( \mathcal{P}\) are provided in the range [first, beyond). More...
 
template<class OutputIterator , class InputIterator , class ITraits >
OutputIterator CGAL::surface_neighbors_3 (InputIterator first, InputIterator beyond, const typename ITraits::Point_2 &p, OutputIterator out, const ITraits &traits)
 The same as above only that the traits class must be instantiated by the user. More...
 
template<class OutputIterator , class InputIterator , class Kernel >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 (InputIterator first, InputIterator beyond, const typename Kernel::Point_3 &p, const typename Kernel::Vector_3 &normal, OutputIterator out, const Kernel &K)
 Similar to the first function. More...
 
template<class OutputIterator , class InputIterator , class Kernel >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 (InputIterator first, InputIterator beyond, const typename Kernel::Point_3 &p, const typename Kernel::Vector_3 &normal, const typename Kernel::FT &max_distance, OutputIterator out, const Kernel &kernel)
 The same as above except that this function takes the maximal distance from p to the points in the range [first, beyond) as additional parameter.
 
template<class OutputIterator , class InputIterator , class ITraits >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 (InputIterator first, InputIterator beyond, const typename ITraits::Point_2 &p, OutputIterator out, const ITraits &traits)
 The same as above only that the traits class must be instantiated by the user. More...
 
template<class OutputIterator , class InputIterator , class ITraits >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 (InputIterator first, InputIterator beyond, const typename ITraits::Point_2 &p, const typename ITraits::FT &max_distance, OutputIterator out, const ITraits &traits)
 The same as above with the parameter max_distance.
 
template<class Dt , class OutputIterator >
OutputIterator CGAL::surface_neighbors_3 (const Dt &dt, const typename Dt::Geom_traits::Point_3 &p, const typename Dt::Geom_traits::Vector_3 &normal, OutputIterator out, typename Dt::Cell_handle start=typename Dt::Cell_handle())
 computes the surface neighbor coordinates with respect to the points that are vertices of the Delaunay triangulation dt. More...
 
template<class Dt , class OutputIterator , class ITraits >
OutputIterator CGAL::surface_neighbors_3 (const Dt &dt, const typename ITraits::Point_2 &p, OutputIterator out, const ITraits &traits, typename Dt::Cell_handle start=typename Dt::Cell_handle())
 The same as above only that the parameter traits instantiates the geometric traits class. More...
 

Function Documentation

template<class OutputIterator , class InputIterator , class Kernel >
OutputIterator CGAL::surface_neighbors_3 ( InputIterator  first,
InputIterator  beyond,
const typename Kernel::Point_3 &  p,
const typename Kernel::Vector_3 &  normal,
OutputIterator  out,
const Kernel &  K 
)

The sample points \( \mathcal{P}\) are provided in the range [first, beyond).

InputIterator::value_type is the point type Kernel::Point_3. The tangent plane is defined by the point p and the vector normal. The parameter K determines the kernel type that will instantiate the template parameter of Voronoi_intersection_2_traits_3<K>.

The surface neighbors of p are computed which are the neighbors of p in the regular triangulation that is dual to the intersection of the 3D Voronoi diagram of \( \mathcal{P}\) with the tangent plane. The point sequence that is computed by the function is placed starting at out. The function returns an iterator that is placed past-the-end of the resulting point sequence.

#include <CGAL/surface_neighbors_3.h>

template<class OutputIterator , class InputIterator , class ITraits >
OutputIterator CGAL::surface_neighbors_3 ( InputIterator  first,
InputIterator  beyond,
const typename ITraits::Point_2 &  p,
OutputIterator  out,
const ITraits &  traits 
)

The same as above only that the traits class must be instantiated by the user.

ITraits must be equivalent to Voronoi_intersection_2_traits_3<K>.

#include <CGAL/surface_neighbors_3.h>

template<class Dt , class OutputIterator >
OutputIterator CGAL::surface_neighbors_3 ( const Dt &  dt,
const typename Dt::Geom_traits::Point_3 &  p,
const typename Dt::Geom_traits::Vector_3 &  normal,
OutputIterator  out,
typename Dt::Cell_handle  start = typename Dt::Cell_handle() 
)

computes the surface neighbor coordinates with respect to the points that are vertices of the Delaunay triangulation dt.

The type Dt must be equivalent to Delaunay_triangulation_3<Gt, Tds>. The optional parameter start is used for the used as a starting place for the search of the conflict zone. It may be the result of the call dt.locate(p). This function instantiates the template parameter ITraits to be Voronoi_intersection_2_traits_3<Dt::Geom_traits>.

This function allows to filter some potential neighbors of the query point p from \( \mathcal{P}\) via its three-dimensional Delaunay triangulation. All surface neighbors of p are necessarily neighbors in the Delaunay triangulation of \( \mathcal{P} \cup \{p\}\).

#include <CGAL/surface_neighbors_3.h>

template<class Dt , class OutputIterator , class ITraits >
OutputIterator CGAL::surface_neighbors_3 ( const Dt &  dt,
const typename ITraits::Point_2 &  p,
OutputIterator  out,
const ITraits &  traits,
typename Dt::Cell_handle  start = typename Dt::Cell_handle() 
)

The same as above only that the parameter traits instantiates the geometric traits class.

Its type ITraits must be equivalent to Voronoi_intersection_2_traits_3<K>.

#include <CGAL/surface_neighbors_3.h>

template<class OutputIterator , class InputIterator , class Kernel >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 ( InputIterator  first,
InputIterator  beyond,
const typename Kernel::Point_3 &  p,
const typename Kernel::Vector_3 &  normal,
OutputIterator  out,
const Kernel &  K 
)

Similar to the first function.

The additional third return value is true if the furthest point in the range [first, beyond) is further away from p than twice the distance from p to the furthest vertex of the intersection of the Voronoi cell of p with the tangent plane defined be (p,normal). It is false otherwise.

#include <CGAL/surface_neighbors_3.h>

template<class OutputIterator , class InputIterator , class ITraits >
std::pair< OutputIterator, bool > CGAL::surface_neighbors_certified_3 ( InputIterator  first,
InputIterator  beyond,
const typename ITraits::Point_2 &  p,
OutputIterator  out,
const ITraits &  traits 
)

The same as above only that the traits class must be instantiated by the user.

ITraits must be equivalent to Voronoi_intersection_2_traits_3<K>. There is no parameter max_distance.

#include <CGAL/surface_neighbors_3.h>