\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 4.9 - 2D Visibility
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CGAL::Rotational_sweep_visibility_2< Arrangement_2_, RegularizationCategory > Class Template Reference

#include <CGAL/Rotational_sweep_visibility_2.h>

Definition

template<typename Arrangement_2_, typename RegularizationCategory = Tag_true>
class CGAL::Rotational_sweep_visibility_2< Arrangement_2_, RegularizationCategory >

This class is a model of the concept Visibility_2 can answer visibility queries within a polygon that may have holes.

The algorithm does not require preprocessing. It relies on the algorithm of T. Asano[1] based on angular plane sweep, with a time complexity of \(O (n \log n)\) in the number of vertices.

Template Parameters
Arrangement_2_is the type used to represent the input environment. It must be an instance of CGAL::Arrangement_2, where its CGAL::Arrangement_2::Traits_2 must be an instance of CGAL::Arr_segment_traits_2, or of CGAL::Arr_non_caching_segment_traits_2.
RegularizationCategoryindicates whether the output should be regularized. It can be specified by one of the following: Tag_true or Tag_false, where Tag_false is the default value.
Is Model Of:
Visibility_2
See Also
CGAL::Simple_polygon_visibility_2
CGAL::Triangular_expansion_visibility_2

Types

typedef Arrangement_2 Arrangement_2
 The type of the input arrangement.
 

Tags

typedef RegularizationCategory Regularization_category
 identifies whether the regularized visibility area is computed (either Tag_true or Tag_false). More...
 
typedef Tag_true Supports_general_polygon_category
 See Visibility_2::Supports_general_polygon_category.
 
typedef Tag_true Supports_simple_polygon_category
 See Visibility_2::Supports_simple_polygon_category.
 

Functions

void attach (const Arrangement_2 &arr)
 Attaches the given arrangement to the visibility object. More...
 

Member Typedef Documentation

template<typename Arrangement_2_ , typename RegularizationCategory = Tag_true>
typedef RegularizationCategory CGAL::Rotational_sweep_visibility_2< Arrangement_2_, RegularizationCategory >::Regularization_category

identifies whether the regularized visibility area is computed (either Tag_true or Tag_false).

Member Function Documentation

template<typename Arrangement_2_ , typename RegularizationCategory = Tag_true>
void CGAL::Rotational_sweep_visibility_2< Arrangement_2_, RegularizationCategory >::attach ( const Arrangement_2 arr)

Attaches the given arrangement to the visibility object.

This operation takes \(O(1)\) as the class does no pre-processing.

In case the object is already attached to another arrangement, the visibility object gets detached before being attached to arr.