CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

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.