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Thread: Center of the screen

  1. #1
    Newbie Newbie
    Join Date
    Sep 2012
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    2

    Center of the screen

    Good morning, every one.

    How do I put the coordinate (0,0) in the center of my window.
    When I draw something it apears on the bottom of the screen.

    Thanks.

  2. #2
    Super Moderator OpenGL Guru
    Join Date
    Feb 2000
    Location
    Montreal, Canada
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    4,264
    ------------------------------
    Sig: http://glhlib.sourceforge.net
    an open source GLU replacement library. Much more modern than GLU.
    float matrix[16], inverse_matrix[16];
    glhLoadIdentityf2(matrix);
    glhTranslatef2(matrix, 0.0, 0.0, 5.0);
    glhRotateAboutXf2(matrix, angleInRadians);
    glhScalef2(matrix, 1.0, 1.0, -1.0);
    glhQuickInvertMatrixf2(matrix, inverse_matrix);
    glUniformMatrix4fv(uniformLocation1, 1, FALSE, matrix);
    glUniformMatrix4fv(uniformLocation2, 1, FALSE, inverse_matrix);

  3. #3
    Newbie Newbie
    Join Date
    Sep 2012
    Posts
    2
    Thanks friend, but when I did this one of my drawings disappeared

  4. #4
    Senior Member OpenGL Pro
    Join Date
    Jan 2012
    Location
    Australia
    Posts
    1,101
    Be careful. The screen coordinates with this method are x -1 to 1, y -1 to 1. You probably need to scale you coordinates to this range. (In fact that is what the projection and view matrices are for).

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