Re: opengl render size too small in X11 window

[Chris Marshall <devel.chm.01@gmail.com>]

Will do.

On Sun, Oct 14, 2018 at 10:13 AM Jon Turney <jon.turney@dronecode.org.uk>
wrote:

> On 11/10/2018 18:40, Chris Marshall wrote:
> > I've verified that if I use the -nowgl option for the X11 server then the
> > opengl visualization is correctly rendered and sized for the containing
> > window.
> >
> > On Wed, Oct 10, 2018 at 12:15 PM Chris Marshall
> > wrote:
> >
> >> Dear Cygwin-
> >>
> >> Using cygwin X11 under windows 10 with a high dpi display (3840x2160)
> >> laptop resulted in far too small font and widgets using -multiwindow for
> >> the XWin option.  If I set the windows setting display resolution to
> >> 1920x1080 and following the suggestion for the ~/.Xresources file from
> >>
> https://stackoverflow.com/questions/42211564/cygwin-xwin-scaling-broken-when-using-windows-scaling-on-high-resolution-displa
> >> I was able keep windows, widgets, and title/menu bars at a reasonable
> size
> >> for reading.
> >>
> >> However, when I display some OpenGL graphics content (using a FreeGLUT
> >> window), then the visible OpenGL rendered area is about 2/3 the apparent
> >> widget area of the X11 window.  If I try the same in a non-multiwindow
> Xwin
> >> session then the rendered area is correct.  This problem is even worse
> if I
> >> try with the full screen resolution.  At the moment I think I have
> narrowed
> >> it down to the -multiwindow support for OpenGL contexts.
> >>
> >> This is with a couple of versions of the freeglut libraries with no
> effect
> >> and the current cygwin and cygwin X Server.
>
> Interesting.  Thanks for reporting this issue.
>
> I suspect this might be caused by:
>
> - the X server is marked as high-dpi aware (via manifest)
> - when using WGL, OpenGL drawing takes place in the client (to a window
> handle retrieved from the X server)
> - the GL client you are using is not marked as high-dpi aware (the default)
>
> (-wgl is only currently supported in multiwindow mode)
>
> If that's the case, I think I see what is needed to fix this, but this
> is not possible for me to test.
>
> I've built an updated libGL1 with this potential fix, perhaps you can
> try it, to see if it improves things. Install it with:
>
> wget ftp://cygwin.com/pub/cygwinx/x86_64/libGL1-18.0.5-1.1.tar.xz
> tar -C / -xvf libGL1-18.0.5-1.1.tar.xz
>
> (This is built for x86_64. If you need x86 instead, please ask)
>
> Reinstall the libGL1 using cygwin setup to get things back to their
> previous state.
>
> --
> Jon Turney
> Volunteer Cygwin/X X Server maintainer
>

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