Re: Debugging GL apps

[Steve Baker <sjbaker1@airmail.net>]

Erik wrote:

> > you
> > a camera that can "walk" over terrain, which worked great under the old
> > NVidia/glx drivers (I have a TNT2).  Under the just released 3.3.5 drivers
> > however, my system locks up solid...I have no idea why.  And it gets even
> 
> I doubt it "locks up solid". You may've lost terminal control... did you try
> telnetting in? (open a telnet port, then run your program)

Or if you can't telnet in because you only have one computer, you can try
this nasty trick:

  * In the main loop of your program do something like repeatedly opening
    a file, writing one byte to it and closing it again.
  * Write a shell script that sits in a loop looking at the time stamp on
    that file...if the file ever gets more than (say) 30 seconds old, run
    a 'killall -9 your_main_program'.
  * Start the shell script running and your main program shortly after.

If your main program 'locks up', the shell script will automatically
try to kill it 30 seconds later.
 
There are more elegant ways to do this (eg with signals and such) - but
this is easy to understand.

> I think you're setting texture coordinates with textures disabled... I got this
> problem a lot doing some texturing on a project... It makes my sw mesa crash
> with the lambda triangle oops. :)

That shouldn't crash Mesa.  I do that all the time in my programs.  If you
disable textures in PPE or my Tux game, it'll do exactly what you did - continue
to send texture coordinates but with texture disabled.  It's certainly not
illegal.

All the glTexCoord command does is to set the current texture coordinate value.
You can do that at any time - the current texture coordinate isn't *used*
unless texture is enabled.

If that's genuinely the case then you should report it as a Mesa bug.
I don't use Mesa's software renderer much - so it's possible I might
not have seen that.
 
-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjbaker1@airmail.net (home)  http://www.woodsoup.org/~sbaker
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