CGAL users discussion list

[Pratyush Pranav <>]

Dear Sebastian, dear all,

I must thank you again. With your help, I managed to reduce my code from 
O(N^2) to O(N).

Something that would have been running in the order of months now runs in the 
order of minutes.

thanks again,

Pratyush


> On 18 May 2016, at 14:20, Sebastien Loriot (GeometryFactory) 
> <>
>  wrote:
> 
> Your vertex class is missing a point data member.
> 
> template <class Refs, class Traits>
> struct My_vertex :
>  public CGAL::HalfedgeDS_vertex_base<Refs, CGAL::Tag_true, typename 
> Traits::Point_3> {
>    typedef typename Traits::Point_3 Point;
>    typedef CGAL::HalfedgeDS_vertex_base<Refs, CGAL::Tag_true, Point> Base;
>    double value;
>    long index;
>    My_vertex() : Base(){}
>    My_vertex(const Point& p) : Base(p) {}
> };
> 
> Sebastien.
> 
> On 05/18/2016 10:54 AM, Pratyush Pranav wrote:
>> Hi Sebastian,
>> 
>> Thanks for pointing out the relevant material.
>> 
>> Now, I try to write a basic code (a modification of one of the examples to 
>> have colour on the faces of the tetrahedron from the CGAL documentation), 
>> to be able to have some of my own items on the vertices, and also have 
>> access to point() on the vertex (this is what is giving me problems). 
>> Could you please help me with where I am going wrong? Below is the code.
>> 
>> pratyush
>> 
>> ————————————————————
>> 
>> #include <CGAL/Simple_cartesian.h>
>> #include <CGAL/Polyhedron_3.h>
>> // A face type with a color member variable.
>> 
>> typedef CGAL::Simple_cartesian<double>        Kernel;
>> 
>> 
>> template <class Refs, class Traits>
>> struct My_vertex : public CGAL::HalfedgeDS_vertex_base<Refs> {
>>      typedef typename Traits::Point_3 Point;
>>     double value;
>>      long index;
>> };
>> // An items type using my face.
>> struct My_items : public CGAL::Polyhedron_items_3 {
>>     template <class Refs, class Traits>
>>     struct Vertex_wrapper {
>>         typedef My_vertex<Refs,Traits> Vertex;
>>     };
>> };
>> 
>> 
>> typedef Kernel::Point_3 Point_3;
>> typedef CGAL::Polyhedron_3<Kernel,My_items>  Polyhedron;
>> typedef Polyhedron::Halfedge_handle           Halfedge_handle;
>> typedef Polyhedron::Vertex_handle           Vertex_handle;
>> int main() {
>>     Point_3 p( 0.0, 0.0, 0.0);
>>     Point_3 q( 1.0, 0.0, 0.0);
>>     Point_3 r( 0.0, 1.0, 0.0);
>>     Point_3 s( 0.0, 0.0, 1.0);
>>     Polyhedron P;
>>     P.make_tetrahedron(p,q,r,s);
>>      Vertex_handle v = P.vertices_begin();
>>      //v->value = 3.14;
>>      v->index = 1;
>>      std::cerr<<v->point()<<" "<<v->index<<std::endl;
>>     return 0;
>> }
>> 
>> 
>> 
>> 
>> 
>>> On 17 May 2016, at 10:03, Sebastien Loriot (GeometryFactory) 
>>> <>
>>>  wrote:
>>> 
>>> It is possible using a custom items traits (second template parameter).
>>> The concept is documented here:
>>> http://doc.cgal.org/latest/Polyhedron/classPolyhedronItems__3.html
>>> 
>>> For an example see how ids are added to simplices in 
>>> CGAL/Polyhedron_items_with_id_3.h
>>> 
>>> Note that using the class Surface_mesh would allow you to do property 
>>> assignment at run-time.
>>> 
>>> http://doc.cgal.org/latest/Surface_mesh/
>>> 
>>> 
>>> Best,
>>> 
>>> Sebastien.
>>> 
>>> On 05/15/2016 02:43 PM, Pratyush Pranav wrote:
>>>> Hi,
>>>> 
>>>> I would like to know if it is possible to derive a polyhedron_3 in such 
>>>> a way that i can store a couple of extra information on the vertices 
>>>> (specifically each vertex should have two additional variables 
>>>> associated with it, one of a double type, and another one of long or int 
>>>> type).
>>>> 
>>>> any leads would be great! thanks in advance!
>>>> 
>>>> pratyush
>>>> 
>>> 
>>> 
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>>> 
>> 
>> 
> 
> 
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