Re: fltk rendering problem

[Martin Helm]

Am 12.10.2012 20:38, schrieb Dmitri A. Sergatskov:
> On Fri, Oct 12, 2012 at 10:41 AM, Martin Helm <address@hidden> wrote:
> ...
>> So it is not a problem of the graphics card driver or the mesa version.
> ...
>
> FWIW:
>
> I see this problem on the computer with intel graphics (i7-2600k/DZ68 m/b) and
> I do not see on the computer with an nvidia card (and nvidia driver).
> (GF106GL [Quadro 2000])
>
> Dmitri.
> --
As I said I see exactly the same behavior (we have intel gpu and nvidia
gpu machines at home, all GNU/Linux systems), it is still not a driver
issue as my own test shows me.
The issue seems to be that something in octave (I will investigate the
details over the weekend) simply does not set proper state variables for
opengl and instead relies on whatever the implementation on the machine
does as default.
This is rarely what one would like to have.
So far I can also not understand what sense it makes to set a linewidth
of 0.5 without at the same time enabling antialiasing, the behavior what
an opengl implementation shall do in such a case seems to be undefined.
The nvidia driver just renders it aliased with a line width of 1, the
intel+mesa implementation seems to try to render "half" of the points.
So if by default we want aliased rendering we should probably have a
default line width which is an integer, not a fraction which cannot be
rendered in a defined way.