Polyhedra generate_polyhedra_from_points(const std::vector<std::array<double,3> >& vertices)
{
std::vector<Point_3> points(vertices.size());
for(int i=0;i<(int)vertices.size();i++)
points[i] = Point_3(vertices[i][0],vertices[i][1],vertices[i][2]);
Polyhedron_3 poly;
CGAL::convex_hull_3(points.begin(), points.end(), poly);
std::transform(poly.facets_begin(), poly.facets_end(), poly.planes_begin(), Plane_from_facet());
for(Halfedge_iterator half=poly.halfedges_begin();half!=poly.halfedges_end();++half)
{
Point_3 v1 = half->vertex()->point();
Point_3 v2 = half->next()->vertex()->point();
Point_3 v3 = half->next()->next()->vertex()->point();
Point_3 v4 = half->opposite()->vertex()->point();
Point_3 v5 = half->opposite()->next()->vertex()->point();
Point_3 v6 = half->opposite()->next()->next()->vertex()->point();
if(coplanar_handmade(v1,v2,v3,v4)&&coplanar_handmade(v1,v2,v3,v5)&&coplanar_handmade(v1,v2,v3,v6)&&
coplanar_handmade(v1,v2,v4,v5)&&coplanar_handmade(v1,v2,v4,v6)&&coplanar_handmade(v1,v2,v5,v6)&&
coplanar_handmade(v1,v3,v4,v5)&&coplanar_handmade(v1,v3,v4,v6)&&coplanar_handmade(v1,v4,v5,v6)&&
coplanar_handmade(v2,v3,v4,v5)&&coplanar_handmade(v2,v3,v4,v6)&&coplanar_handmade(v2,v3,v5,v6)&&
coplanar_handmade(v2,v4,v5,v6)&&coplanar_handmade(v1,v3,v5,v6)&&coplanar_handmade(v3,v4,v5,v6))
{
poly.join_facet(half);
half=poly.halfedges_begin();
}
}
int cur = 0;
for(auto it=poly.points_begin(); it!=poly.points_end(); it++, cur++)
points[cur] = *it;
cur = 0;
std::vector<std::vector<int> > faces;
for(Facet_iterator i=poly.facets_begin(); i!=poly.facets_end(); i++)
{
faces.push_back(std::vector<int>());
Halfedge_facet_circulator j = i->facet_begin();
do
{faces[cur].push_back(std::distance(poly.vertices_begin(), j->vertex()));} while (++j != i->facet_begin());
cur++;
}
return Polyhedra{points,faces};
}
int main()
{
CGAL::Random_points_in_sphere_3<Point_3, PointCreator> gen(100.0);
// generate 250 points randomly on a sphere of radius 100.0
// and copy them to a vector
std::vector<Point_3> points;
CGAL::cpp11::copy_n( gen, 250, std::back_inserter(points) );
// define polyhedron to hold convex hull
Polyhedron_3 poly;
// compute convex hull of non-collinear points
CGAL::convex_hull_3(points.begin(), points.end(), poly);
std::cout << "The convex hull contains " << poly.size_of_vertices() << " vertices" << std::endl;
// assign a plane equation to each polyhedron facet using functor Plane_from_facet
std::transform( poly.facets_begin(), poly.facets_end(), poly.planes_begin(),Plane_from_facet());
return 0;
}
