Shape_detection: using proper triangulated polygonal faces for linear_least_squares

[soesau]

Summary of Changes

Polygonal faces are now triangulated and face normals are calculated using PMP::compute_face_normal.

The calculated face normals and triangulations are buffered in Least_squares_plane_fit_region. However, Least_squares_plane_fit_sorting is independent and does not benefit from that buffered data.

Release Management

• Affected package(s): Shape_detection
• Issue(s) solved (if any): fix #7992

[lrineau]

@afabri @sloriot @MaelRL: This bug-fix pull-request adds new dependencies to non-trivial parts of PMP. For the license checking, that means a user of CGAL-5.6.1 might have a new license issue after an update to CGAL-5.6.2. That does not seem right.

[soesau]

Sebastien motivated yesterday having a basic triangulation for exactly cases like this. Here a simple triangulation of simple polygons is required. Using PMP::triangulate_hole_polyline creates all those mentioned dependencies.

[sloriot]

runtime error of test_region_growing_on_degenerated_meshfor shape detection in CGAL-6.0-Ic-279

[sloriot]

Successfully tested in CGAL-6.0-Ic-282

[afabri]

Can we not identify three points which are maximal un-collinear, by computing Eigen values/vectors ?

[github-actions[bot]]

This pull-request was previously marked with the label Tested, but has been modified with new commits. That label has been removed.

[sloriot]

Successfully tested in CGAL-6.0-Ic-307

[lrineau]

I have removed the label https://github.com/CGAL/cgal/labels/Not%20yet%20approved.

I hope this merge PR was eventually approved. The issue I pointed out was the addition of dependencies: https://github.com/CGAL/cgal/pull/8314#issuecomment-2195684005.