Bug#405859: xserver-xorg-video-mga: freeglut error if there's no Virtual line in xorg config file
Hi,
On Tue, Jan 09, 2007 at 09:07:15AM +0100, Michel Dänzer wrote:
> On Mon, 2007-01-08 at 23:12 +0100, Jens Seidel wrote:
> > Section "ServerFlags"
> > Option "AIGLX" "off"
> > EndSection
> >
> > Section "Extensions"
> > Option "Composite" "Disable"
> > EndSection
>
> The latter disables the Composite extension, which isn't related to
> AIGLX and disabled by default anyway (unless the Debian X server is
> patched to change that, I'm losing track).
>
> > > BTW, what exactly is GLUT_ALPHA supposed to achieve?
> >
> > I'm not sure but believe it just enables Alpha Blending, e.g.
s/e.g./i.e./ (stupid latin abbreviations)
> > transparency.
>
> Yes, AFAICT from a web search it requests that the drawable contains an
> alpha component, which is only supported with the Composite extension.
> So maybe changing the second option above to enable the Composite
> extension makes a difference?
No, it doesn't. Please note that I no longer search a solution, I assume
it's just an error in the mga driver module as indicated by the many
warnings and errors. I doubt it is a configuration issue (otherwise the
default config file should be created properly by Xorg for new installs).
Maybe it is also an OpenGL issue which doesn't allow me to try other
options (GLUT_RGB instead of GLUT_ALPHA) if one is not supported since
it seems to stop immediately IIRC.
> Note that blending such a drawable against
> another drawable will not work correctly with hardware acceleration
You refer to the Matrox driver not the general case, right?
> currently though. Also note that GLUT_ALPHA is not necessary for alpha
> blending while rendering to the drawable.
Since I'm not completely sure about this I prefer not to remove it.
Otherwise it could result in bogus effects.
Jens
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