CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

You need to extend the Homogenous and then plug it inside 
Extended_Homogeneous. If you look in the header file, you'll see
that no Point_3 is defined.

Sebastien.

On 04/25/2012 09:50 AM, Johannes Ulen wrote:
> Hello again,
> No the code is not compiling when I inherit from Extended_Homogeneous,
> only when I Inherit from Homogeneous. The difference I could work out
> in the code was that the a base struct was defined for Homogeneous but
> not for Extended_homogeneous. And the way inheritance is shown in the
> manual is via this base struct.
>
> - Johannes.
>
>
> On Wed, 2012-04-25 at 08:45 +0200, Sebastien Loriot (GeometryFactory)
> wrote:
> > I am not sure to understand your question, the code you posted was
> > correct and was compiling, isn't?
> >
> > Sebastien.
> >
> > On 04/24/2012 12:54 PM, Johannes Ulen wrote:
> > > Thank you!
> > > With minor adjustment the code you sent did exactly what I needed.
> > >
> > > For my curiosity (and futher people ending up here when they search for
> > > my problem) I still do not understand how to inherit from
> > > Extended_homogeneous kernel and why  the syntax would be different than
> > > inheriting from the homogeneous kernel.
> > >
> > > - Johannes
> > >
> > > On Tue, 2012-04-24 at 08:37 +0200, Sebastien Loriot (GeometryFactory)
> > > wrote:
> > > > On 04/23/2012 02:55 PM, 
> > > >
> > > >  wrote:
> > > > > I'm trying the add one property to the point class.
> > > > >
> > > > > By help from  StackOverflow I was directed to Manual Chapter 11.5 Extensible
> > > > > Kernel using this I wrote the code below.
> > > > >
> > > > > The code  will not compile and I get the error:
> > > > > ‘typename CGAL::Extended_homogeneous::Base’ names
> > > > > 'CGAL::Extended_homogeneous::Base’, which is not a class template|
> > > > >
> > > > > == CODE ==
> > > > > #include<CGAL/Extended_homogeneous.h>
> > > > >
> > > > > template<    typename K_, typename K_Base>
> > > > > class My_base  : public K_Base::template Base<K_>::Type
> > > > > {
> > > > >      typedef typename K_Base::template Base<K_>::Type   OldK;
> > > > >
> > > > > public:
> > > > >      typedef K_                             Kernel;
> > > > >
> > > > >      template<    typename Kernel2>
> > > > >      struct Base { typedef My_base<Kernel2, K_Base>     Type; };
> > > > >     };
> > > > >
> > > > > template<    typename RT_>
> > > > > struct MyKernel  : public CGAL::Type_equality_wrapper<My_base<MyKernel<RT_>,
> > > > > CGAL::Homogeneous<RT_>    >,  MyKernel<RT_>    >
> > > > > {};
> > > > >
> > > > > #include<CGAL/Nef_polyhedron_3.h>
> > > > > typedef MyKernel<CGAL::Gmpz>      Kernel;
> > > > >
> > > > > typedef CGAL::Nef_polyhedron_3<Kernel>    Nef_Polyhedron;
> > > > > typedef Nef_Polyhedron::Plane_3  Plane;
> > > > >
> > > > > int main()
> > > > > {
> > > > >      Nef_Polyhedron half_space(Plane(1,1,1,1), Nef_Polyhedron::EXCLUDED);
> > > > >
> > > > >      return 0;
> > > > > }
> > > > > ====
> > > > >
> > > > > If the inhertiance is changed to "public K_Base::Base::template B<K_>::Type" 
> > > > > it
> > > > > will compile but Then I miss the propeties from Extentensions I guess? Because
> > > > > I get the error "Constructor not available for this kernel" when I run the
> > > > > program.
> > > >
> > > > The point constructors are not changed by this mechanism. This means
> > > > that only those documented are available. If you want to initialize your
> > > > extra data, you need to first create an object of type My_point and then
> > > > init a point of type MyKernel::Point_3 with it.
> > > >
> > > > The class in the kernel is a kind of interface while My_point is the
> > > > representation.
> > > >
> > > > Sebastien.