CGAL users discussion list

[Joshua A Levine <>]

Hi CGALers,

I was wondering about the mechanism for storing hidden vertices in the 
Regular_Triangulation_3 class.  It seems that unlike in the 2D case, these 
vertices are only stored as a list of weighted points associated with 
whichever cell they are contained in.  There seems to be no global way to 
access all of the hidden points for the triangulation (outside of checking 
every cell).  Is this correct?

Moreover, because they are stored as a list of weighted points instead of as 
a list of actual vertices, it doesn't seem like there is a mechanism for 
storing additional information associated with these vertices.  By this I 
mean if I have a custom Vertex class with some additional members, and if I'd 
like to use that class to store additional information for a point I want to 
insert, I may not be able to if that point becomes hidden.  Is there a 
recommended way to store this sort of information without using some external 
bookkeeping?  Is there even a moderately easy way to do it _with_ external 
bookkeeping?

To keep it simple for discussion purposes, consider a Regular_Triangulation_3 
class where I want to store an associated id for each vertex I insert.  But 
the triangulation is changing with both insertions and deletions, so at any 
time a point I insert could itself be hidden, or could hide other vertices 
already present.  Similarly, on deletion I could unhide some points, but I'm 
pretty sure never hide anything.

Thanks,
Josh