cgal-discuss - Re: Re : [cgal-discuss] A problem with iso oriented box intersection

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Re: Re : [cgal-discuss] A problem with iso oriented box intersection

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Subject: Re: Re : [cgal-discuss] A problem with iso oriented box intersection
Date: Thu, 11 Dec 2008 13:32:36 +0100 (CET)

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Hello,

My answer to just rename callback to operator() was too simplistic.

The object is passed as a copy and not as a reference. That means

that the list is copied.

So you need a light-weight object with a pointer to the heavy weight

object of type My_class.

This is not particular for CGAL but normal for function objects, e.g.

functors in STL algorithms.

andreas

On Thu, 11 Dec 2008 11:27:26 +0000 (GMT), BBB HHH wrote: Hello,

I used the operator() which resolved the problem. But i have another
problem. The operator() is given below:

void operator()(const& Box a, const Box
// Here i want to compute the index of the box a in the list of boxes by
finding the distance between the box1.handle() (which is of type //
std::list::iterator) and the trinagles.begin() (which is also of the same
type). The index allows me to find corresponding //triangles in my list of
triangles and do futher processing.
}

My program compiles successfully but it crashes when trying to

execute the
line inside the operator().
I am using Visual Studio 2005 with SP. The error is "list iterators
incompatible".

My program is included below.
Thanks in advance
Hichem Barki

#include
#include
#include
#include
#include
#include
#include

using std::cout;
using std::cin;
using std::endl;

template
class My_class
{
public:
typedef typename Kernel::FT Number_type;
typedef typename Kernel::Point_2 Point_2;
typedef typename Kernel::Point_3 Point_3;
typedef typename std::list< Triangle_3> Triangles;
typedef typename Triangles::iterator tri_it;

typedef CGAL::Box_intersection_d::Box_with_handle_d Box;

// Member data
Triangles triangles; // List of the superset triangles

// Constructors
My_class(...)
{
// Fill the list of Triangles
.....

}
void operator()(const& Box a, const Box
}
void get_inters_bboxes()
{
// Create the corresponding vector of bounding boxes
std::vector boxes;
for (tri_it iter = triangles.begin(); iter !=

triangles.end(); ++iter)
boxes.push_back( Box( iter->bbox(), iter));

// Run the self intersection algorithm with all defaults
CGAL::box_self_intersection_d(boxes.begin(), boxes.end(), callback, 10,
CGAL::Box_intersection_d::HALF_OPEN);
}

};

-------------------------
DE : Pierre Alliez
:

ENVOY LE : Mercredi, 10 Dcembre 2008, 12h14mn 29s
OBJET : Re: [cgal-discuss] A problem with iso oriented box intersection
package

hi Hichem,

that is tricky indeed - have already encountered this issue which was
solved with the help of Andreas Fabri.

I send you my self_intersect global function, which takes as parameters a
CGAL polyhedron, and an output iterator where I write all triangles which
interesect. as you can see I can pass to the intersection engine a class
Intersect_facets with a parameterized constructor.

the callback function is the operator () of that class.

good luck!

pierre

BBB HHH a crit : Hello,

I am working with the

CGAL::box_self_intersection_d to detect
interrsections in a list of bboxes of triangles. I want to do this in an
object oriented manner (inside a class). Some parts of my code are listed
below. I can not compile my program since there are several errors in the
line using box_self_intersection_d.
I think the error is the use of the callback of box_self_intersection_d.
In my program this callback is a class member function. In the examples
provided by CGAL. The callback is a global function and the
box_self_intersection_d function is called inside main(). Can someone help
me to detect the problem (how to put a function object inside a class
template and how to use it correctly). I tried a global function as a
callback, the compile succeds but i can not acces the member data of my
class.

Thanks in advance
Hichem BARKI

#include
#include
#include
#include
#include
#include
#include

using std::cout;
using std::cin;
using std::endl;

template
class My_class
{

public:
typedef typename Kernel::FT Number_type;
typedef typename Kernel::Point_2 Point_2;
typedef typename Kernel::Point_3 Point_3;
typedef typename std::list< Triangle_3> Triangles;
typedef typename Triangles::iterator tri_it;

typedef CGAL::Box_intersection_d::Box_with_handle_d Box;

// Member data
Triangles triangles; // List of the superset triangles

// Constructors
My_class(...)
{
// Fill the list of Triangles
.....

}
void callback(const& Box a, const Box font-size: x-small;"> void
get_inters_bboxes()
{
// Create the corresponding vector of bounding boxes
std::vector boxes;
for (tri_it iter = triangles.begin(); iter != triangles.end(); ++iter)
boxes.push_back( Box( iter->bbox(), iter));

// Run the self intersection algorithm with all defaults
CGAL::box_self_intersection_d(boxes.begin(), boxes.end(), callback, 10,
CGAL::Box_intersection_d::HALF_OPEN);
}

};

--
Pierre Alliez
INRIA Sophia Antipolis - Mediterranee
Project-team GEOMETRICA

http://www-sop.inria.fr/members/Pierre.Alliez/
Tel: +33 4 92 38 76 77
Fax: +33 4 97 15 53 95

--=_abaa58435ed1bfb9f1c74434826d3a3a
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html; charset="UTF-8"

Hello,
My answer to just rename callback to operator() was too simplistic.
The object is passed as a copy and not as a reference. That means
that the list is copied.
So you need a light-weight object with a pointer to the heavy weight
object of type My_class.
This is not particular for CGAL  but  normal for function obje=
cts, e.g.
functors in STL algorithms.
 
andreas
 
On Thu, 11 Dec 2008 11:27:26 +0000 (GMT), BBB HHH
<h_hachimodo@yahoo=
=2Efr> wrote:
<blockquote style=3D"border-left: 2px solid #1010ff; padding-left: 5px; mar=
gin-left: 5px; width: 100%;">
<div style=3D"font-family:times new roman,new york,times,serif;font-size:14=
pt">
<div>Hello, I used the operator() which resolved the problem. Bu=
t i have another problem. The operator() is given below: void operator()</=
span>(const& Box a, const Box& b) { Triangles::differen=
ce_type index =3D std::distance(triangles.begin(), box1.handle()); //=
Here i want to compute the index of the box a in the list of boxes by find=
ing the distance between the box1.handle() (which is of type // std=
::list::iterator) and the trinagles.begin() (which is also of the same type=
). The index allows me to find corresponding //triangles in my list of tr=
iangles and do futher processing. } My program compiles su=
ccessfully but it crashes when trying to execute the line inside the operat=
or(). I am using Visual Studio 2005 with SP. The error is "list iterat=
ors incompatible". My program is included below. Thanks in =
advance Hichem Barki #include =
 #include #include #include #include #inc=
lude #include using std::cout; using std:=
:cin; using std::endl; template class My_class<br=
/> { public: typedef typename Kernel::FT =
Number_type; typedef typename Kernel::Point_2 =
Point_2; typedef typename Kernel::P=
oint_3 Point_3; typedef typename s=
td::list< Triangle_3> Triangles; =
typedef typename Triangles::iterator =
tri_it; typedef CGAL::Box_intersection_d::Box_with_handl=
e_d Box; // Member data Triangles =
triangles; // List of the superset =
triangles // Constructors My_class(...) { //=
Fill the list of Triangles ..... } void <s=
pan style=3D"font-family: Default Sans Serif,Verdana,Arial,Helvetica,sans-s=
erif; font-size: x-small;">operator()(const& Box a, const Box&am=
p; b) { Triangles::difference_type index =3D std::distance(tria=
ngles.begin(), box1.handle()); } =
void get_inters_bboxes() { // Create the corresponding vector o=
f bounding boxes std::vector boxes; for (tri_it iter =3D triang=
les.begin(); iter !=3D triangles.end(); ++iter) boxes.push_back( Box(=
iter->bbox(), iter)); // Run the self intersection algorit=
hm with all defaults CGAL::box_self_intersection_d(boxes.begin(), box=
es.end(), callback, 10, CGAL::Box_intersection_d::HALF_OPEN); } =
 }; </div>
<div style=3D"font-family: times new roman,new york,times,serif; font-size:=
14pt;"> 
<div style=3D"font-family: times new roman,new york,times,serif; font-size:=
12pt;">
<hr size=3D"1" />
De : Pierre Alli=
ez À :</stro=
ng>
 Envoyé le : Mercredi, 10 Décembre 20=
08, 12h14mn 29s Objet :</sp=
an> Re: [cgal-discuss] A problem with iso oriented box intersectio=
n package hi Hichem, that is tricky indeed =
- have already encountered this issue which was solved with the help of An=
dreas Fabri. I send you my self_intersect global function, whi=
ch takes as parameters a CGAL polyhedron, and an output iterator where I wr=
ite all triangles which interesect. as you can see I can pass to the inters=
ection engine a class Intersect_facets with a parameterized constructor.<br=
/> the callback function is the operator () of that class. <b=
r /> good luck! pierre BBB HHH a éc=
rit :
<blockquote>
<div style=3D"font-family: times new roman,new york,times,serif; font-size:=
14pt;">
<div style=3D"font-family: times new roman,new york,times,serif; font-size:=
14pt;">
<div style=3D"font-family: times new roman,new york,times,serif; font-size:=
12pt;">Hello, I am working with =
the CGAL::box_self_intersection_d to detect interrsections in a list of bbo=
xes of triangles. I want to do this in an object oriented manner (inside a =
class). Some parts of my code are listed below. I can not compile my progra=
m since there are several errors in the line using box_self_intersection_d. I think the error is the use of =
the callback of box_self_intersection_d=
=2E In my program this callback is a class member function. In the examples=
provided by CGAL. The callback is a global function and the box_self_intersection_d function is called inside mai=
n(). Can someone help me to detect the problem (how to put a function objec=
t inside a class template and how to use it correctly). I tried a gl=
obal function as a callback, the compile succeds but i can not acces the me=
mber data of my class. Thanks in advance Hichem BARKI<br=
/> #include #include <br=
/> #include #include #include #include #includ=
e using std::cout; using std::cin; using s=
td::endl; template class My_class { public:=
 typedef typename Kernel::FT =
Number_type; typedef typename Kernel::Point_2 =
Point_2; typedef typename Kernel::Point_3 =
Point_3; typedef typename std::list< Triang=
le_3> Triangles; typedef typename T=
riangles::iterator tri_it; =
 typedef CGAL::Box_intersection_d::Box_with_handle_d Box; // Member data Triangles =
triangles; // List of the superse=
t triangles // Constructors My_class(...) { =
// Fill the list of Triangles ..... } void =
callback(const& Box a, const Box&am=
p; b) { // DO some processing with the member data of My_class<=
br /> } void get_inters_bboxes() =
{ // Create the corresponding vector of bounding boxes std::vec=
tor boxes; for (tri_it iter =3D triangles.begin(); iter !=3D triangle=
s.end(); ++iter) boxes.push_back( Box( iter->bbox(), iter)); =
 // Run the self intersection algorithm with all defaults CGAL=
::box_self_intersection_d(boxes.begin(), boxes.end(), callback, 10, CGAL::B=
ox_intersection_d::HALF_OPEN); } }; =
 </div>
</div>
</div>
 </blockquote>
 
<pre class=3D"moz-signature">-- Pierre Alliez INRIA Sophia Antip=
olis - Mediterranee Project-team GEOMETRICA <a class=3D"moz-txt=
-link-freetext" rel=3D"nofollow" href=3D"http://www-sop.inria.fr/members/Pi=
erre.Alliez/" target=3D"_blank">http://www-sop.inria.fr/members/Pierre.Alli=
ez/</a>
Tel: +33 4 92 38 76 77
Fax: +33 4 97 15 53 95
</pre>
</div>
</div>
</div>
 </blockquote>
--=_abaa58435ed1bfb9f1c74434826d3a3a--

Re: Re : [cgal-discuss] A problem with iso oriented box intersection, andreas . fabri, 12/11/2008

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Re: Re : [cgal-discuss] A problem with iso oriented box intersection