Bug#393150: kpovmodeler: fails to completely display some scenes

[Alexandre DENIS <contact@alexandredenis.net>]

> that looks a like a bug from your openGL driver, sorry pal, that
> works for me, and i see no way on how to reproduce that, so there
> won't be a bug report, and there won't be a fix without that.

It's definitely a GL-related bug, you're right. I am now able to make it 
work or not work depending on the mesa configuration. More precisely:

-- DRI: ok
(with libgl1-mesa-glx and libgl1-mesa-dri, DRI enabled in xorg.conf)

-- GLX: *bug*
(with libgl1-mesa-glx only; libgl1-mesa-dri uninstalled)

-- GL software rasteriser: ok
(with libgl1-mesa-swx11 installed; libgl1-mesa-glx and libgl1-mesa-dri 
uninstalled)

I guess you may reproduce the bug when uninstalling libgl1-mesa-dri (or 
maybe simply disable DRI in xorg.conf). Surprisingly, the "Direct 
rendering" switch in kpovmodeler settings has no impact on the bug.

The bug is most probably in libgl1-mesa-glx or in the "glx" module from 
xserver-xorg-core.