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CGAL 6.0 - 2D Visibility
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#include <CGAL/Rotational_sweep_visibility_2.h>
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.
| 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. |
| RegularizationCategory | indicates 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. |
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). | |
| 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. | |
| 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).
| 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.