Re: fltk / gl rendering problem

[marco atzeri <marco.atzeri@gmail.com>]

Il 6/21/2013 1:32 PM, Jon TURNEY ha scritto:
> On 17/06/2013 07:48, marco atzeri wrote:
>> Il 6/16/2013 4:51 PM, marco atzeri ha scritto:
>>> testing a octave/fltk graphics issue, I noticed that also the
>>> demo of fltk with GL interface has a similar issue.
>
> Thanks for reporting this and thanks for providing the test binaries.
>
>>> On http://matzeri.altervista.org/works/fltk_gl/
>>> I uploaded the before and after apperance of "gl_overlay" demo.
>>>
>>> It is enough to move the window to loose the geometrical
>>> image while the bars are correctly re-drawn.
>>>
>>> Running Xwin with -wgl does not show such defect, but it is
>>> terribly slow. So I assume it is not a fltk defect but of
>>> GL or XServer.
>
> I guess this should read "with -nowgl", in which case, this is a limitation of
> the current implementation of -wgl mode, which will require lots of work to fix.

Question: is "-wgl" disabled by some of the other Xwin options ?
I was sure all my previous experiments where with "-wgl"
But I see no difference between
"xwin -rootless -nowgl" and "xwin -rootless"

> I wrote a bit about these limitations at [1]
>
> [1] http://www.cygwin.com/ml/cygwin-xfree/2012-10/msg00009.html

It seems the same defect so it seems related to "-wgl",
at least in multiwindow mode.

Testing with
" xwin -multiwindow "
    the moving defect is present and slide layer are drawn

" xwin -multiwindow -nowgl"
    the moving defect is NOT present but the slide layer are NOT drawn
( same for both "xwin -rootless -nowgl" and "xwin -rootless" )


>> further experiment showed that the defect is present when the integrate
>> windows manager is used. With external window manager (fvwm, openbox,.. ) that
>> defect does not apper.
>>
>> With external window manager another defect appears, the upper
>> bar effect is not shown at all; while it is present on the integrated
>> window manager.
>
> When I tested this, it looks like the solid area controlled by the "sides"
> slider didn't get rendered into a separate layer when using software rendering
> (either -nowgl or X server in windowed mode), so this is possibly some bug or
> limitation in the software renderer, or possibly in a bug in the demo not
> recognizing the lack of capabilities of the software renderer.

Do you mean more likely a OpenGL bug of fltk one ?

Regards
Marco




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