Thread: SDL/OpenGl seg fault help.

  1. #1
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    SDL/OpenGl seg fault help.

    Registered new type: STL Vector
    Setting breakpoints
    Debugger name and version: GNU gdb 6.7.50.20071127
    Child process PID: 2780
    Program received signal SIGSEGV, Segmentation fault.
    In SDL_GL_SwapBuffers () (C:\Documents and Settings\Public\My Documents\NewSDL_PROJECT\SDL.dll)


    apparently from what I can tell is that the problem lies in SDL_GL_SwapBuffers(). But that cant be right...can it?

    the program runs just fine...its just when I try exit that it faults on me.

    http://members.gamedev.net/ridejocka...DL_PROJECT.zip
    Last edited by eaane74; 07-11-2008 at 10:36 AM. Reason: added link

  2. #2
    Frequently Quite Prolix dwks's Avatar
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    The problem is that you call SDL_Quit() when escape is pressed. Then your loop
    Code:
        while(m_Running)
        {
            while(SDL_PollEvent(&event))
            {
                OnEvent(&event);
            }
    
            OnLoop();
    
            glClear(GL_COLOR_BUFFER_BIT);
    
            OnRender();
    
            SDL_GL_SwapBuffers();
        }
    goes on to execute SDL functions (i.e. SDL_GL_SwapBuffers()), which won't work after you've called SDL_Quit().

    So, here's what I suggest you do. Instead of calling SDL_Quit(), use
    Code:
    m_Running = 0;
    I'd then follow your logic to make sure SDL_Quit() is called eventually.

    I compiled and ran your project under Linux with no troubles, in case you're interested about portability.

    BTW, please put a default case where you switch on an SDLKey -- with warnings enabled, you get hundreds of warnings about unhandled enumeration values . . . .
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
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  3. #3
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    thanks....I was beating my head against the wall trying to figure that one out. It had me completely stumped.

    I was going to as about the enumeration warnings. I thought it was because I was using a switch statement instead of if else statements. It is pretty annoying when your compiler goes through about 300 warnings every time you recompile the project.

  4. #4
    and the hat of int overfl Salem's Avatar
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    > It is pretty annoying when your compiler goes through about 300 warnings every time you recompile the project.
    So fix them all then!
    Then when you get 1 new warning (when you previously had zero), you'll be able to see it instantly.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  5. #5
    Frequently Quite Prolix dwks's Avatar
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    It's very easy to fix. As I mentioned, you just need to put
    Code:
    default:
        break;
    where ever you switch on an enum. I think that only occurs in one place, where you switch() on an SDLKey.
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
    "The only real mistake is the one from which we learn nothing." -- John Powell


    Other boards: DaniWeb, TPS
    Unofficial Wiki FAQ: cpwiki.sf.net

    My website: http://dwks.theprogrammingsite.com/
    Projects: codeform, xuni, atlantis, nort, etc.

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