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Thread: Color matrix

  1. #1
    Senior Member OpenGL Guru
    Join Date
    Dec 2000
    Location
    Reutlingen, Germany
    Posts
    2,042

    Color matrix

    Hi,

    i would like to use the color matrix to adjust brightness and contrast. I read in a book how to do this, but it seems not to work:

    glMatrixMode (GL_COLOR);
    glTranslatef (0.5,0.5,0.5);

    (I call those functions after glClear, but before everything is drawn.)

    This should darken everything i think, but it just happens nothing.

    I checked for error codes, but there are none. I checked the required extension (ARB_imaging), but itīs there (Geforce 2).
    So, where could be the error?

    Hope someone knows how to do it properly.

    Jan.
    GLIM - Immediate Mode Emulation for GL3

  2. #2
    Junior Member Newbie
    Join Date
    Oct 2002
    Location
    Los Angeles, Ca, USA
    Posts
    21

    Re: Color matrix

    Appears you are using it correctly.
    What are you drawing?
    Color Matrix should work with
    glDrawPixels as well as glTexSubImage2D
    but I dont believe it works with
    primatives like lines or polys.

    Also, wont work with the new ati radeon
    drivers at all. Nvidia is generally supported
    but slow slow slow.

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