CGAL users discussion list

[Fernando Cacciola <>]

Rob,

> Fernando,
>
>
>   I went with the first method just to get things working, and it seems
> to have turned out fairly well! 

Great :)


> One other idea I had, and on which I
> thought you might give me some direction, is on overloading the
> EdgeCollapse class
> (CGAL/Surface_mesh_simplification/Detail/Edge_collapse.h).  Basically,
> I'd like to register a visitor callback that is executed *directly
> after* an edge collapse.  My vertices and halfedges have some custom
> attributes, and I'd like to modify the attributes of surrounding
> halfedges and vertices after a collapse.  Currently, there is no
> callback executed after an edge collapse, so this is not possible.  I
> could go into the EdgeCollapse source code and modify it to allow this
> callback, but I'd rather write a simple class which extends or adapts
> EdgeCollapse and just re-implements the Collapse function to allow that
> extra callback.  Can you think of a good way to do this (as the
> functions in EdgeCollapse are not declared virtual)?  Thanks again for
> all your help!

In cases like this what I often do is:

  1.Make a verbatim copy of the class header(s) under a new name

  2.Rename the class within the copy

  3.Make changes right there in the renamed class, or based on the 
renamed class inheriting from it BUT only after having refactored it out 
to add or extend polymorhism support.

C++ just lacks what other OO languages call modules (Ruby) or extension 
methods (CLI 3.5) which is technically what you need here.

Best

Fernando