I updated my OS yesterday (from Kubuntu KK to LL) and after the update I get this error message while executing my ruby game with Gosu. What did I forget to (re-)install?

$ ruby game.rb
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
./kyobasic.rb:101: [BUG] Segmentation fault
ruby 1.8.7 (2010-01-10 patchlevel 249) [i486-linux]

The same thing happened on ruby 1.9.1p378 (2010-01-10 revision 26273) [i486-linux]

I know it's not my script fault since I haven't made any changes on it since yesterday when it still worked fine.

Edit...

It seems this has something to do with Linux BUT NOT Gosu.

Reedit...

I just forgot to edit this post but after a forced system reboot I was kind of lazy hehehe.

No, it has nothing to do with Gosu. As long as even glxgears cannot find Xlib, your system is officially borked. (Luckily! I have enough ugly stuff to fix ;P)

Here's the error message I've got after closing the game window.

$ ruby1.9 kaerdon.rb

X Error of failed request:  BadDrawable (invalid Pixmap or Window parameter)
  Major opcode of failed request:  145 (XFree86-DRI)
  Minor opcode of failed request:  9 ()
  Resource id in failed request:  0x3800004
  Serial number of failed request:  1140
  Current serial number in output stream:  1140

I guess this has nothing to do with Gosu but Linux, but could anyone tell me what's wrong here? Everything works fine until I hit the cancel button and I know it's the correct code.

exit if button_down?(Gosu::KbEscape) or button_down?(Gosu::KbQ)

If this has nothing to do with the code, then what could be the real cause of the error message?

(The only reason why I could continue working on Gosu was because I had previously install Kubuntu HH 8.04.3 LTS on my system. There I don't get any errors regarding GLX module.)

You should use "close" instead of "exit". "exit" is a system function that brutally kills the process.

OK, I thought it was something more serious than that. Thanks for your advice. (Sometimes I forget about avoiding using exit explicitly.)

BTW, the first issue was resolved. The mistery behind that was that for some weird reason the dist-upgrade thought I had installed a nvidia graphic card which I never did. That's why it complained about not finding the GLX extension since there was no such card on my PC to make it work properly.