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Thread: glTexImage2D

  1. #1


    Hello !

    I've read many post on this forum
    about the bad perfs of glReadPixel,
    more generally about all the transfer
    to video memory.
    What about glTexImage2D ? Is this function
    as slow as glReadPixel ? More generally,
    is it possible to generate new texture
    at each frame at a reasonnable frequency ?
    Are there extensions like (sthg)_range
    that could speed up the thing ? Has
    anyone already done such thing ?

    Thx for all your advices and comments


  2. #2
    Senior Member Regular Contributor
    Join Date
    Apr 2001

    Re: glTexImage2D

    About glReadPixels : it is slow because it retrieves data from the graphics card, which is not designed to send data back to the host; it is designed to receive and process data.

    About dynamic textures : use glTexSubImage instead of glTexImage. You won't achieve very high performance if you use large dynamic textures, though.
    At the moment, there is no multi-vendor extension for efficient dynamic texturing. For NVIDIA chips, there is NV_pixel_data_range.

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