CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

The intersection type in this case is either a segment (line coplanar 
with a face, or edge on the line) or a point.

As in the example you copy-pasted, you need to first get the
intersection type before printing it (the part using boost::get).

Best,

Sebastien.

On 04/14/2017 04:03 PM, Edouard rivière wrote:
> Hi,
>
>
>
> I try to use CGAL to perform line/mesh intersection, so I began with the
> examples in the documentation. I compiled the '3D Fast intersection and
> Distance Computation'
> (http://doc.cgal.org/latest/AABB_tree/AABB_tree_2AABB_polyhedron_facet_intersection_example_8cpp-example.html)
> that works fine.
>
>
>
> Then I tried to retrieve the coordinates of all intersection points
> obtained after     tree.all_intersections(segment_query,
> std::back_inserter(intersections));
>
>
>
> by using this code :
>
>
>
> for(std::list<Segment_intersection>::iterator it =
> intersections.begin(); it!=intersections.end(); it++) {
>
>      std::cout << *it << std::endl;
>
> }
>
>
>
> I get error message 'error: invalid application of ‘sizeof’ to
> incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>'
>
>
>
> Is it possible to get some help at this point ?
>
>
>
> best regards
>
>
>
>
>
>
>
> // Author(s) : Camille Wormser, Pierre Alliez #include <iostream>
> #include <list> #include <CGAL/Simple_cartesian.h> #include
> <CGAL/AABB_tree.h> #include <CGAL/AABB_traits.h> #include
> <CGAL/Polyhedron_3.h> #include
> <CGAL/boost/graph/graph_traits_Polyhedron_3.h>
>
> #include <CGAL/AABB_face_graph_triangle_primitive.h>
>
> typedef CGAL::Simple_cartesian<double> K; typedef K::Point_3 Point;
> typedef K::Plane_3 Plane; typedef K::Vector_3 Vector; typedef
> K::Segment_3 Segment; typedef K::Ray_3 Ray; typedef
> CGAL::Polyhedron_3<K> Polyhedron; typedef
> CGAL::AABB_face_graph_triangle_primitive<Polyhedron> Primitive; typedef
> CGAL::AABB_traits<K, Primitive> Traits; typedef CGAL::AABB_tree<Traits>
> Tree; typedef boost::optional<
> Tree::Intersection_and_primitive_id<Segment>::Type >
> Segment_intersection; typedef boost::optional<
> Tree::Intersection_and_primitive_id<Plane>::Type > Plane_intersection;
> typedef Tree::Primitive_id Primitive_id; int main() {
>
>     Point p(1.0, 0.0, 0.0);
>
>     Point q(0.0, 1.0, 0.0);
>
>     Point r(0.0, 0.0, 1.0);
>
>     Point s(0.0, 0.0, 0.0);
>
>     Polyhedron polyhedron;
>
>     polyhedron.make_tetrahedron(p, q, r, s);
>
>     // constructs AABB tree
>
>     Tree tree(faces(polyhedron).first, faces(polyhedron).second,
> polyhedron);
>
>     // constructs segment query
>
>     Point a(-0.2, 0.2, -0.2);
>
>     Point b(1.3, 0.2, 1.3);
>
>     Segment segment_query(a,b);
>
>     // tests intersections with segment query
>
>     if(tree.do_intersect(segment_query))
>
>         std::cout << "intersection(s)" << std::endl;
>
>     else
>
>         std::cout << "no intersection" << std::endl;
>
>     // computes #intersections with segment query
>
>     std::cout << tree.number_of_intersected_primitives(segment_query)
>
>         << " intersection(s)" << std::endl;
>
>     // computes first encountered intersection with segment query
>
>     // (generally a point)
>
>     Segment_intersection intersection =
>
>         tree.any_intersection(segment_query);
>
>     if(intersection)
>
>     {
>
>         // gets intersection object
>
>       const Point* p = boost::get<Point>(&(intersection->first));
>
>       if(p)
>
>         std::cout << "intersection object is a point " << *p << std::endl;
>
>     }
>
>     // computes all intersections with segment query (as pairs object -
> primitive_id)
>
>     std::list<Segment_intersection> intersections;
>
>     tree.all_intersections(segment_query,
> std::back_inserter(intersections));
>
>
>
> // show all intersection ???
>
>
>
>     // computes all intersected primitives with segment query as
> primitive ids
>
>     std::list<Primitive_id> primitives;
>
>     tree.all_intersected_primitives(segment_query,
> std::back_inserter(primitives));
>
>     // constructs plane query
>
>     Vector vec(0.0,0.0,1.0);
>
>     Plane plane_query(a,vec);
>
>     // computes first encountered intersection with plane query
>
>     // (generally a segment)
>
>     Plane_intersection plane_intersection =
> tree.any_intersection(plane_query);
>
>     if(plane_intersection)
>
>     {
>
>
>
>       if(boost::get<Segment>(&(plane_intersection->first)))
>
>             std::cout << "intersection object is a segment" << std::endl;
>
>     }
>
>
>
>     return EXIT_SUCCESS;
>
> }