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Thread: NVidia - transform feedback issue ???

  1. #1
    Junior Member Newbie
    Join Date
    Sep 2010
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    5

    NVidia - transform feedback issue ???

    I have used transform feedback to store results of some computationally more demanding shaders and draw them in later updates. It works fine on my desktop Quadro FX 3800, but doesn't on my notebook GeForce 9300M. Problem seems to be related to glDrawTransformFeedback call, because when I replace this call by corresponding glDrawArrays, everything work as it should. Also the GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN query returns correct value and buffer object contains valid data. So it seems to me like some driver issue with glDrawTransformFeedback. (Maybe the number of primitives to be drawn is not correctly set???)

    Here are configurations of my computers:

    1) desktop (working)

    Suse 11.2 x86_64, X.Org version: 1.6.5, NVidia driver 256.53
    some glGetStrings:
    Renderer: Quadro FX 3800/PCI/SSE2
    Version: 3.3.0 NVIDIA 256.53
    Shading language version: 3.30 NVIDIA via Cg compiler

    2) notebook (not working):
    Suse 11.3 x86_64, X.Org version: 1.8.0, NVidia driver 256.53
    some glGetStrings:
    Renderer: GeForce 9300M GS/PCI/SSE2
    Version: 3.3.0 NVIDIA 256.53
    Shading language version: 3.30 NVIDIA via Cg compiler

    If it will be usefull, I can post relevant fragments of sources too.

    Thanks for any advice.

  2. #2
    Advanced Member Frequent Contributor
    Join Date
    Jan 2007
    Posts
    965

    Re: NVidia - transform feedback issue ???

    Feedback is a deprecated feature. See also: http://www.opengl.org/wiki/Common_Mi..._Feedback_Mode

    It's quite possible that your app will run faster without feedback anyway.

  3. #3
    Junior Member Regular Contributor
    Join Date
    Sep 2006
    Location
    thailand
    Posts
    130

    Re: NVidia - transform feedback issue ???

    I think he mean "Transform feedback" not the old "Feedback mode".

  4. #4
    Junior Member Newbie
    Join Date
    Sep 2010
    Posts
    5

    Re: NVidia - transform feedback issue ???

    Yes, I really meant Transform Feedback - functions like glGenTransformFeedbacks, glBeginTransformFeedback, glDrawTransformFeedback etc.

    Is it the right place to post this, or should I write to some NVidia forum? Does anyone have some experiences with reporting such problems?

  5. #5
    Member Regular Contributor
    Join Date
    Nov 2003
    Location
    Czech Republic
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    318

    Re: NVidia - transform feedback issue ???

    My experience is that NVIDIA people (Piers Daniell, Barthold Lichtenbelt) monitor this forum. But there is no guarantee.

    Filling NVIDIA bug report doesn't hurt.

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