Re: [UFO-devel] Bug#385945: boson: crashes on singleplayer game start

[Johannes S. <sch...@us...>]

Le Samedi 16 Septembre 2006 02:06, Andreas Beckermann a =C3=A9crit=C2=A0:
[...]
> I have done some additional research and have been able to reproduce the
> bug on one of my own machines. It happens with mesa based drivers only. It
> appears to me that this is a bug in mesa, in particular I believe it is
> http://www.mail-archive.com/mesa3d-dev%40lists.sourceforge.net/msg00772.h=
tm
>l The fact that this problem goes away with libgl1-mesa-dri
> 6.5.0.cvs.20060524-1 seems to confirm that, as current mesa versions don't
> include the fix yet, cvs does.

Hmm, I'm using here libgl1-mesa-dri 6.4.1-0ubuntu8 and can't reproduce the=
=20
problem.
If you can create a minimal example, please send it to the libufo mailing=20
list.

> However I have no idea how to write around this problem so that it works
> for broken mesa versions, too. The only way I can see atm is not to use
> vertex arrays, but this solution _really_ sucks and would require quite
> some changes to libufo.

IIRC, the only place where we are using vertex arrays in libufo is in=20
GL_Graphics::drawVertexArray.
You could replace the vertex array with plain glBegin, glVertex, glEnd call=
s.
But using immediate mode is a performance penalty ...
(though it shouldn't be too slow, as there are usually only a few vertices=
=20
drawn. Compared to a RTS, it's really "low-poly" rendering)

The VertexArray object returns interleaved arrays. Looping over all vertice=
s=20
with glVertex and glColor should work (but getting OpenGL vertex arrays to=
=20
work would certainly be better).
Send me an email if you need help with that ...

> CC'ing libufo-devel for this problem, maybe some good idea comes up.
> Additional information for libufo developers:
> It stems from usage of vertex arrays in libufo, however I have not yet
> managed to narrow it down to the exact combination of circumstances
> (meaning I haven't had time to write a few test cases yet).
> From what I have found by now, I think it happens only when using
> ufo::UVertexArray with triangles (i.e. not with lines). IIRC it was
> PE_IndicatorRadioButton in UBasicStyle::paintPrimitive() that triggered t=
he
> bug for me.

It's strange that this occurs only with triangles ...


Best,
Johannes