CGAL users discussion list

[kierans <>]

Hi Efi,

I wasn't aware of the parameter that indicates whether to report endpoints or not - that may well explain why the number of intersections is 3 instead of 5. My bad :)

What about the values reported for the intersections themselves ? The values are negative and dont seem to match what I got drawing the example by hand. Is there some strange coordinate system in use ?? I've probably got the wrong end of the stick but I reckon the answers should be:

* (3,3)
* (3,5)
* (5,5)
* (8,8)
* (8,5)

not

* (-21/-7, -21/-7)
* (-3/-1, -5/-1)
* (-35/-7, -35/-7)

Apologies in advance for my ignorance :)

Cheers,

Kieran

On Sat, Jan 19, 2013 at 9:03 PM, Efi Fogel [via cgal-discuss] <[hidden email]> wrote:

I don't see the problem.

The forth argument of compute_intersection_points() indicates whether to report endpoints. By default the value of this argument is false. Thus, only 3 intersections are reported.

On Sat, Jan 19, 2013 at 12:36 PM, kierans <[hidden email]> wrote:

Hi there,

I built CGAL-4.1 and managed to get the
Arrangement_on_surface2_example/sweep_line to build and run. Unfortunately
for me it gives total bogus results :( It gets the number of intersections
and their values wrong.

From my reading of the example it should find 5 intersections at the
following locations:

* (3,3)
* (3,5)
* (5,5)
* (8,8)
* (8,5)

When I debug the example I get the following output:

Found 3 intersection points:
-21/-7 -21/-7
-3/-1 -5/-1
-35/-7 -35/-7

I am running on windows 7,  Microsoft Visual Studio VC++ 2010 Express
(32-bit), Boost 1.51 (32-bit) and CGAL-4.1. Any ideas on what's going on ?

Cheers,

Kieran








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