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  • OpenGL Tip...

    Hi there.

    First off, I'm sorry in advance if I posted this to the wrong forum, but it seemed
    to be the most applicable.

    One thing I've been meaning to mention...

    One way to speed-up the OpenGL refresh rate, is to disable the Vertical-Sync option
    under your graphic-card's OpenGL options. I've gone from 60 to well-over 480 fps
    with most of the "demos".

    As with this sort of info, your mileage will vary.

    Later!

    ------------------
    Scott Martindale
    [email protected]
    Scott Martindale
    [email protected]

  • #2
    Hi Scott,

    I've done the same thing with DirectX apps (turn off V-Sync), but that also introduced a heavy flickering on both of my machines... Is this not the case with OpenGL?

    ------------------
    Best regards,
    Mark Geurds

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    • #3
      Hi Mark.

      Not on either of the two machines I have. Though a lot of it may
      depend on your graphics card, and how (well) it supports OpenGL.

      Another thing to consider is, that OpenGL is by nature/design,
      more OS-independent than DirectX. So where DirectX may need the
      sync for its own internal reasons, OpenGL may be "self-sufficient"
      enough to handle similar timing requirements in other ways.

      Heck, for the amount of extra work you need to put into developing
      an OpenGL app vs. a DirectX app, you should get something out of it!

      If/when you get the chance, I'm curious to see if you get the same
      flickering issues in OpenGL as you did in DirectX with v-sync disabled.

      Take care!



      ------------------
      Scott Martindale
      [email protected]
      Scott Martindale
      [email protected]

      Comment


      • #4
        Scott,
        my monitor can't display 480 frames per second. I suspect yours can't either.

        What's the point of writing that fast to a video card when 6 out of every 7 frames you calculate are overwritten by the next frame before being displayed?

        Surely OpenGL has some way to detect if the last frame sync has occurred so you can do something useful while waiting for the frame sync instead of calculating and "displaying" graphics which never make it to the screen?

        Paul.




        ------------------

        Comment


        • #5
          Hi Paul.

          You're right. My monitor for example, has a limit of 120hz. All the v-sync disabling does
          is to allow the OpenGL card to operate without having to concern itself with a "speed limit".

          In many circumstances, it won't matter, while at other times it will. It all depends on the
          complexity of what it's having to do, and if it has to "wait" for the next sync pulse, or
          if it can just go-on to the next task. No too unlike removing a self-imposed wait state.

          Later!

          ------------------
          Scott Martindale
          [email protected]

          [This message has been edited by Scott J. Martindale (edited May 02, 2003).]
          Scott Martindale
          [email protected]

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