CGAL users discussion list

[Hexley <>]

Hi, I'm actually OP's colleague and responsible for the CGAL module of our
code, but I'm having some trouble implementing a custom traits to make use
of the spherical kernel intersect function, as you suggested.

I decided to make a model of AABBGeomTraits. Since I only need to redefine
the Intersect_3 functor and construction function, I figured I could make my
custom traits a subclass of a spherical kernel. I followed the procedure
descibed in the documentation, and also made my own Intersect_3 replacement
functor, as shown below.

/// Class used as substitute for Intersect_3
class SphericalIntersect {

  typedef Spherical SK;
public:
  typedef std::pair<SK::Circular_arc_point_3, UInt> pair_type;
  typedef boost::variant<pair_type> variant_type;
  typedef boost::optional<variant_type> result_type;

  typedef CGAL::cpp11::result_of<SK::Intersect_3(SK::Line_arc_3,
                                                 SK::Sphere_3,
                                                
std::back_insert_iterator&lt;std::list&lt;variant_type> >)
                                                 >::type cpp11_type;
  result_type
  operator()(const CGAL::Line_arc_3<SK> & a, const CGAL::Sphere_3<SK> & b) {
    std::list<variant_type> list;
    CGAL::intersection(a, b, std::back_inserter(list));
    return boost::make_optional(list.front());
  }
};

/**
 * @brief Class used as AABBGeomTraits in the CGAL AABB tree algorithm
 *
 * The inheritance from another kernel is described in CGAL documentation
 */
template<typename SK, typename K_base> // SK is new kernel, K_base is old
one
class SphericalTraits_base : public K_base::template Base<SK>::Type {
  
  typedef typename K_base::template Base<SK>::Type OldK;

public:
  typedef SphericalIntersect Intersect_3;

  Intersect_3 intersect_3_object() {
    return Intersect_3();
  }

  template<typename Kernel>
  struct Base {
    typedef SphericalTraits_base<Kernel, K_base> Type;
  };
};

template<typename FT_>
struct SphericalTraits : public CGAL::Type_equality_wrapper<
                         SphericalTraits_base<SphericalTraits&lt;FT_>,
                        
CGAL::Spherical_kernel_3<CGAL::Simple_cartesian&lt;FT_>,
                         CGAL::Algebraic_kernel_for_spheres_2_3<FT_> > >,
                         SphericalTraits<FT_> >
{};

I am then using SphericalTraits<double> in the CGAL::AABB_traits class.
Every type of point, sphere, line_arc, etc., used in the algorithm is
related to the kernel Spherical which refers to
CGAL::Spherical_kernel_3<CGAL::Simple_cartesian&lt;double>,
CGAL::Algebraic_kernel_for_spheres_2_3<double> >. I am also using a custom
AABBPrimitive class which redefines :

Id = unsigned int
Point = Spherical::Circular_arc_point_3
Datum = Spherical::Line_arc_3

I have a small example which constrcuts the tree and asks a query, but it
doesn't compile, and I get this error : 
/usr/local/include/CGAL/AABB_tree.h:1061:4: error: no matching function for
call to ‘std::pair<CGAL::Point_3&lt;akantu::SphericalTraits&lt;double> >,
unsigned
int>::pair(CGAL::internal::Primitive_helper<CGAL::AABB_traits&lt;akantu::SphericalTraits&lt;double>,
akantu::Line_arc_primitive>, false>::Reference_point_type, const Id&)’
    points.push_back(

But at this point I would just like to know if I'm on the right track.
Thanks in advance !



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