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Thread: Is glDrawPixels really so slooow ?

  1. #1
    Junior Member Newbie
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    Jun 2000
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    Is glDrawPixels really so slooow ?

    Hi

    I wanted to have some rotating object
    in front of some background pic.
    I use glDrawPixels to display the pic
    and then I draw the object.
    But glDrawPixels() slows everything down.
    Is there no other way to display a background
    pic ? (Besides storing the bg pic as a texture and drawing a huge polygon)

    regards
    Tom

  2. #2
    Senior Member OpenGL Guru Humus's Avatar
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    Re: Is glDrawPixels really so slooow ?

    I really think you should use textures since it's fastest and is no harder to use.

  3. #3
    Junior Member Newbie
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    Re: Is glDrawPixels really so slooow ?

    Probably you're right, but it is really
    amazing how much time glDrawPixels needs
    to copy a 320x240 big image into the video
    ram...

  4. #4
    Senior Member Regular Contributor
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    Redlands, CA, USA
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    Re: Is glDrawPixels really so slooow ?

    I guess, glDrawPixels doesn't use temporary array to store source pixels.
    It means, that glDrawPixels cannot just push some commands in the buffer for pipelined processing. It must wait, until all previous operations are complete.
    It is very bad for 3D pipeline.

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