Geometry Boost List: Re: [geometry] Reproducible bug ?

Subject: Re: [geometry] Reproducible bug ?
From: Barend Gehrels (barend_at_[hidden])
Date: 2012-12-29 07:21:20

Hi,

On 28-12-2012 11:07, Romain Texier wrote:
> Hi,
>
> I make the union of some triangles and an exception is thrown. The 
> exception is overlay_invalid_input_exception.
> The triangles are provided by a mesh for a rendering tool. A mesh must 
> share some points.
>
>

Using float, the triangles are close to the resolution of the floating 
point grid. Therefore the exception occurs. If you use double, the 
exception disappears (in my case). If that is not enough, you should use 
the ttmath, which is accurate. Boost.Geometry supports ttmath for these 
purposes. Be sure to use "ttmath_big", which is a derived type having a 
default constructor.

So like this:

#include <boost/geometry/extensions/contrib/ttmath_stub.hpp>
...
     typedef boost::geometry::model::d2::point_xy<ttmath_big> 
BoostPoint;                  // 2D float point

But for this specific example, double was OK for me.

Can you verify if that solves your other problem ("Re: [geometry] union 
gives an empty multi-polygon") too? It seems related to me.

Regards, Barend