Re: [Boost-users] [Boost.Geometry] - Union generates polygon with punctures

Subject: Re: [Boost-users] [Boost.Geometry] - Union generates polygon with punctures
From: Olivier Heriveaux (hodevel_at_[hidden])
Date: 2013-07-13 04:42:45

> The policy of this list is: don't top-post. I reordered your mail to read
> from top to bottom, my answers in between.
>

Sorry for the inconvenient, I knew it but gmail hid your answer in my reply
form (have to click a button to show it)...

> So only in float we have the real spike. The output is indeed not checked
> on these cases. They should not be generated but in float they apparently
> are, because of the lower resolution.
>

So this could really be considered as an issue ? Do you think a solution
could correct this behaviour or must we deal with it ? I'm not asking for a
fix, I currently use Boost.Polygon to achieve what I want - just wanted to
test it with Boost.Geometry since it can work with float (I currently
convert my float space to int space to work with Boost.Polygon). As I found
this corner case I thought it could be usefull to report it.

> Did you try the complete program (so including the steps after this union)
> with double? Is it then also reporting the self-intersection? You probably
> cannot use float for this case... We can filter out the spike in a
> post-process, as you suggest, but it is (at least not now) the intention to
> do this by default.
>

It requires many changes in my program, it is a currently in a big project
(point type is not a template since I knew I wanted floating numbers). I
will try to extract the entire algorithm and make a simple test program for
it.

Regards, Olivier.