Use O(N log N) sweep-line for polygon simplicity check

[atta-ullah01]

Summary of Changes

This PR replaces the inefficient implementation of is_polygon_simple in MVC_post_processor_3.h (which checked every pair of edges for intersection) with the efficient sweep-line algorithm provided by CGAL::is_simple_2.

This change improves the complexity of the simplicity check from $O(N^2)$ to $O(N \log N)$ and resolves the @fixme annotation previously present in the code.

Release Management

• Affected package(s): Surface_mesh_parameterization
• Issue(s) solved (if any): Resolves an internal fixme
• Feature/Small Feature (if any): Optimization
• Link to compiled documentation (obligatory for small feature):
• License and copyright ownership: I confirm that I have the right to contribute these changes.

[afabri]

This creates a dependency on the Polygon package.
We have to check that the sweep line version is certified for a kernel without exact constructions. Well, the quadratic one, also does not give any guarantee if the predicates are not exact.

[afabri]

Can you please add Polygon to the file dependencies

[afabri]

This creates a dependency on the Polygon package. We have to check that the sweep line version is certified for a kernel without exact constructions. Well, the quadratic one, also does not give any guarantee if the predicates are not exact.

The dependency is on a LGPLed package, which is fine.
No constructions are made.

[atta-ullah01]

Can you please add Polygon to the file dependencies

Done. I have added Polygon to the dependencies file.

[sloriot]

Successfully tested in CGAL-6.2-Ic-82