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Thread: OpenGL bugs on specific platforms only?

  1. #1
    Junior Member Newbie
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    OpenGL bugs on specific platforms only?

    Hi,

    Does anyone know if there is a site listing implementations of OpenGL that are buggy and how to work-around their problems? I am repeatedly coming up against weird behaviour on certain graphics cards.

    My software works fine on my computer (of course!), but users sometimes report
    weird behaviour. Takes a long time to track it down when I don't have access
    to their machine. For example, drawing bitmap text during GL picking mode
    crashes on many laptops!

    Here's the latest one I'm stuck with:

    I have a call to glColor3f() that isn't doing anything on one user's machine. I draw stuff before in another colour, change the colour, draw other stuff, but the new stuff comes out in the first colour. Remember, it works fine on ALL other computers I've encountered. I sent a diagnostic version and got the following info:

    GL_VENDOR: 'Intel'
    GL_RENDERER: 'Intel 845G'
    GL_VERSION: '1.3.0 - Build 4.14.10.3889'

    I also called the following before and after glColor3fv():

    glGetFloatv(GL_CURRENT_COLOR, c);

    And output the result to a diagnostic file. Sure enough, GL still thinks it's using the previous colour, unchanged by glColor3fv().

    Weird thing is that the same code is used at another time and it works as expected, so there must be some difference in rendering state that causes this. It is not an intermittent problem though, it happens consistantly.

    Anyone encountered this before? Any general tips for how to remotely debug such an issue?

    Thanks,
    Rob.

  2. #2
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    Re: OpenGL bugs on specific platforms only?

    Color for what?

    If you want to change color of bitmap fonts, then you must call glSetRasterPos or smthn. after you have changed color. Color of raster operations isn't updated otherwise.

  3. #3
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    Re: OpenGL bugs on specific platforms only?

    Originally posted by M/\dm/\n:
    Color for what?

    If you want to change color of bitmap fonts, then you must call glSetRasterPos or smthn. after you have changed color. Color of raster operations isn't updated otherwise.
    Just for drawing lines, with:
    Code :
    		glBegin(GL_LINES);
    		glVertex2dv(p1);
    		glVertex2dv(p2);
    		glEnd();
    Don't forget, this works on EVERY other machine I've tried, and no one else has reported the problem, so I don't think I'm actually doing anything wrong. It's specific to this Intel graphics card. I find it's quite common for laptops to have problems with one or two aspects of OpenGL.

    Rob.

  4. #4
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    Re: OpenGL bugs on specific platforms only?

    if you search in the advanced forum for "intel" and "opengl" you'll find some matches like No Hardware Acceleration

    intel doesn't seem to be a first choice for OpenGL

  5. #5
    Junior Member Regular Contributor execom_rt's Avatar
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    Re: OpenGL bugs on specific platforms only?

    Originally posted by RobertWebb:
    Hi,

    Does anyone know if there is a site listing implementations of OpenGL that are buggy and how to work-around their problems?
    I think that such of site would never happens.
    It would be immediately shutted down due to NDA problems by the vendors, and the site owner would be sued for DMCA or something.

    Just imagine a few secs. By exploiting one of the OpenGL bugs (especially crash-bugs), someone could write a virus or something to exploit the crash and gain administrator priviledges ...

  6. #6
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    Re: OpenGL bugs on specific platforms only?

    Originally posted by execom_rt:
    By exploiting one of the OpenGL bugs (especially crash-bugs), someone could write a virus or something to exploit the crash and gain administrator priviledges ...
    Really? I can write a program that crashes and doesn't even need OpenGL (I do it all the time ).

    I found a work-around, by calling glFlush() before the call to glColor3f(). It only needs to be done once per frame, so hopefully it isn't a performance hit on other platforms.

    Rob.

  7. #7
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    Re: OpenGL bugs on specific platforms only?

    Originally posted by RobertWebb:

    I found a work-around, by calling glFlush() before the call to glColor3f(). It only needs to be done once per frame, so hopefully it isn't a performance hit on other platforms.
    That seems somewhat funny bug - looks like the driver's OpenGL operations' queue was full at the time you called glColor3f() and so your call was simply rejected / ignored.

  8. #8
    Junior Member Regular Contributor execom_rt's Avatar
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    Re: OpenGL bugs on specific platforms only?

    Really? I can write a program that crashes and doesn't even need OpenGL (I do it all the time ).
    Yes, but it's your program. The crash in opengl would be in a SYSTEM DLL, so with administrator rights.

    Moreover, this DLL would be present in much more computers than your program

  9. #9
    Senior Member OpenGL Guru
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    Re: OpenGL bugs on specific platforms only?

    Does anyone know if there is a site listing implementations of OpenGL that are buggy and how to work-around their problems? I am repeatedly coming up against weird behaviour on certain graphics cards.
    IIRC there was something from intel? a few years ago, a replacement to opengl32.dll or someit. anyways IIRC there was a bit of info about various cards and various problems with them (of course it prolly hasnt been maintained but u never know)

  10. #10
    Senior Member OpenGL Pro sqrt[-1]'s Avatar
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    Re: OpenGL bugs on specific platforms only?

    Just a post for historical purposes:

    I was also getting a crash on Intel 845G chipsets. (only this chipset, the newer Intel chipsets were fine)

    It turns out that it does not like using hardware-mipmap generation and crashes in the driver when it is being used. (even tho it is in the extension string)

    I found this by knocking out each OpenGL extension one by one, (via GLIntercept) until the crash went away.

    Hopefully this may be of some use to other people.

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