Explain how to get points from a mesh

[oleg-alexandrov]

The documentation at https://doc.cgal.org/latest/Surface_mesh/index.html focuses on iterators and circulators. It would be nice to have an example to to actually get a vertex value from a mesh. This looks like a very primitive operation to me.

It may also help to show to create a list of points as well, or a point set, given that many operations in CGAL (such as Poisson reconstruction) start with vertices, and not with meshes, even if the goal is mesh processing.

[sloriot]

I guess you mean accessing the coordinates of a vertex. It is a bit burred in the doc here: One property is maintained by default, namely "v:point". The value of this property has to be supplied when adding a new point to the data structure via Surface_mesh::add_vertex(). The property can be directly accessed using Surface_mesh::points() or Surface_mesh::point(Surface_mesh::Vertex_index v). This examples uses the point() method.

A list of points is just a range of points like std::vector<Point_3>.