Bug#423739: libgl1-mesa-dri: banding in rendering when using blending for transparency
On Mon, 2007-05-14 at 03:21 -0400, Dan Torop wrote:
>
> When using blending for transparency, banding occurs in the output
> and colors have a greenish cast.
Does this also happen when rendering say a GL_QUAD instead of using
glBitmap?
> version indirect rendering r200 DRI on
> ---------------- ------------------ ------------
> Debian 6.5.1-0.6 banding 50% gray
> Debian 6.5.2-4 banding banding
> Debian 6.5.3~rc3-1 banding banding
> released 6.5.2 (DRI) banding 50% gray
> released 6.5.3 (DRI) banding 50% gray
> released 6.5.3 (xlib) 50% gray n/a
>
> Unless I'm totally making a hash of diagnosing this, it seems that:
>
> - Somehow the Debian-compiled versions of Mesa exhibit a bug which
> vanilla version of Mesa does not exhibit??
As indirect rendering seems to fail consistently (the xlib backend
works completely differently), did you double-check that these cases
were really using direct rendering?
> - There is an inconsistency between indirect and direct rendering (at
> least for the R200) in Mesa. I can't speak to cards besides the
> R200.
Note that when AIGLX is enabled (check Xorg.0.log), the Mesa *_dri.so
driver will be used in both cases, though in contrast to direct
rendering the X server will only load it once on X startup.
> I'm reporting this against libgl1-mesa-dri, though perhaps it could
> as easily be against libgl1-mesa-glx or the mesa source package?
Or xserver-xorg-core...
> Please excuse me if I am utterly flubbing the testing of this and it
> isn't a real bug. I'd be very excited if it were reproducible on
> another computer...
Can't reproduce it with the r300 driver from more or less up to date
Mesa GIT here even with indirect rendering.
> or if it turned out to not be reproducible and was a result of a silly error here.
Can't see any obvious errors FWIW.
--
Earthling Michel Dänzer | http://tungstengraphics.com
Libre software enthusiast | Debian, X and DRI developer
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