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[placebo <>]

Hello,

I am trying to find all intersections between a "triangle" and a "triangle
soup" using AABB trees. I have posted a simple example here to illustrate my
problem:

Consider 6 triangles arranged in a hexagonal pattern. 5 of the triangles
make up the soup. The 6th triangle is the query.  

The "all_intersections" function should return:
3 point intersection objects
and
2 segment intersection objects

However, when I execute the script (see below), I get the following output:

5 intersection(s) with triangle query
intersection object is a point
intersection object is a point
intersection object is a point
intersection object is a point
intersection object is a point
Finished

Do AABB triangle trees not work with "triangle" queries?

I am using:
Windows 7
boost 1.53.0 (32 bit) 
mingw with gcc-4.7.2 (32 bit) 
CGAL-4.2 (32 bit) 

Thanks,

-Willie B. Maddox Ph.D.


// BEGIN "AABB_triangle_3_example2.cpp"
#include <iostream>
#include <list>

#include <CGAL/Simple_cartesian.h>
#include <CGAL/AABB_tree.h>
#include <CGAL/AABB_traits.h>
#include <CGAL/AABB_triangle_primitive.h>

typedef CGAL::Simple_cartesian<double> K;

typedef K::Point_3 Point;
typedef K::Triangle_3 Triangle;
typedef K::Segment_3 Segment;

typedef std::list<Triangle>::iterator Iterator;
typedef CGAL::AABB_triangle_primitive<K,Iterator> Primitive;
typedef CGAL::AABB_traits<K, Primitive> AABB_triangle_traits;
typedef CGAL::AABB_tree<AABB_triangle_traits> Tree;
typedef Tree::Object_and_primitive_id Object_and_primitive_id;

int main()
{
    Point p0( 0.0, 0.0, 0.00);
    Point p1( 1.0, 0.5, 0.05);
    Point p2( 0.0, 1.0, 0.05);
    Point p3(-1.0, 0.5, 0.05);
    Point p4(-1.0,-0.5, 0.05);
    Point p5( 0.0,-1.0, 0.05);
    Point p6( 1.0,-0.5, 0.05);

    std::list<Triangle> triangles;
    triangles.push_back(Triangle(p0,p2,p3));
    triangles.push_back(Triangle(p0,p3,p4));
    triangles.push_back(Triangle(p0,p4,p5));
    triangles.push_back(Triangle(p0,p5,p6));
    triangles.push_back(Triangle(p0,p6,p1));

    // constructs AABB tree
    Tree tree(triangles.begin(),triangles.end());

    // counts #intersections
    Triangle triangle_query(p0,p1,p2);
    std::cout << tree.number_of_intersected_primitives(triangle_query)
        << " intersections(s) with triangle query" << std::endl;

    // computes all intersections with segment query (as pairs object -
primitive_id)
    std::list<Object_and_primitive_id> isects;
    tree.all_intersections(triangle_query, std::back_inserter(isects));

    for (std::list<Object_and_primitive_id>::iterator isect =
isects.begin(); isect != isects.end(); isect++)
    {
        // get intersection objects
        Object_and_primitive_id op = *isect;
        CGAL::Object object = op.first;
        Segment segment;
        Point point;
        if(CGAL::assign(segment,object))
            std::cout << "intersection object is a segment" << std::endl;
        else if(CGAL::assign(point,object))
            std::cout << "intersection object is a point" << std::endl;
        else std::cout << "intersection object is unknown" << std::endl;
    }

    std::cout << "Finished" << std::endl;
    return EXIT_SUCCESS;
}
// END "AABB_triangle_3_example2.cpp"





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