Sorry for my late reply.
Finally I had time to test your suggestion Richard.
The problem seems to be solved when I change the depth display of my X
server. I used always the 16 bit mode to get a good graphic performance with my old geforce card. I changed to 24bit but it`s a bit the nasty way, isn`t it?

Now I get some other errors with flightgear, but they have nothing to do with freeglut. I guess, I have to install flightgear from CVS sources (incl. openal). The old freebsd port seems to be broken.
By the way... the flightgear port from the portscollection points to libglut 6.0.1 (not freeglut).


But the makefile installs flightgear with freeglut. :)

Greetings  Karim

>  From: Richard Rauch <sforge@olib.org> ;
>  To:   <freeglut-developer@lists.sourceforge.net> ;
>  Subject: Re: [Freeglut-developer] assertion failed in freeglut_window.c
>  On Sun, Jan 23, 2005 at 07:29:28PM +0000, Karim Forsthofer wrote:
>  >  Hello  >  
>  >  I tried to run flightgear 0.9.6 on my freebsd box. It depends on
>  freeglut, simgear, plib ...etc.
>  [...]
>  >  Assertion failed: (window->  Window.VisualInfo!=NULL),function
>  fgOpenWindow, file freeglut_window.c
>  This sounds like the infamous "freeglut used to use asert() as a general
>  purpose error check".
>  Basically, what it's telling you is that it could not obtain an X visual
>  for the video mode on your current display.  I'd guess that this
>  is due to flightgear asking for an alpha channel (though it might
>  be caused by other display mode request types).  One user has
>  reported seeing this on a 15bpp or 16bpp X server when asking for
>  an alpha channel; he reported that he was able to solve the problem
>  by running his X server in 24bpp mode.
>  So, try exiting your X server and re-start it.  E.g., with XFree86 4.x,
>  you could do this:
>   startx -- -depth 24
>  ...to get a 24-bit display.
>  Try 15, 16, 24, and 32 as fairly common sizes that may work.
>  >  It seems to be a freeglut problem, that`s why I post it here. There
>  are already a few messages in the mailinglist about it, but nothing that
>  would help me to go on or to fix it.
>  Well, the above suggestion had been made before.
>  Possibly you missed it?  Or maybe you saw it and assumed that it wasn't
>  the issue?  Or maybe you tried the solution already and it doesn't work?
>  >  Any sugesstions?
>  Just the one.  (^&
>  --
>   "I probably don't know what I'm talking about."
>   http://www.olib.org/~rkr/
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