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Thread: Rotating airplane

  1. #1
    Junior Member Newbie
    Join Date
    Sep 2004
    Location
    Norway
    Posts
    2

    Rotating airplane

    Hi,

    I have a problem with drawing an airplane in my OpenGL application. I know the orientation of the airplane from two vectors: One vector that is parallell to the body of the airplane, pointing forward, and one vector pointing straight up through the "roof" of the airplane. To draw my airplane-model I want to rotate to match the object-space defined by the two vectors, but I don't know how to do it. Any help would be appreciated.

    Thanks.

  2. #2
    Junior Member Newbie
    Join Date
    Aug 2004
    Posts
    16

    Re: Rotating airplane

    Well, you have the perfect data for getting the orientation of your air plane. Basically you have 2 of 3 components of an orientation matrix. You have the Z and Y so you simply need to find the X by doing a cross product.

    Z = Forward Normal
    Y = Up Normal
    X = Y cross Z

    Where the actual cross product would look like...
    X.x = Y.y * Z.z - Y.z * Z.y
    X.y = Y.z * Z.x - Y.x * Z.z
    X.z = Y.x * Z.y - Y.y * Z.x

    Then to render the plane, you can simply call glMultMatrix in OpenGL and send it a pointer to your column major 4x4 matrix data.

    If you have not already, I would invest some time in creating a reasonable vector library or finding an existing one.

  3. #3
    Junior Member Newbie
    Join Date
    Sep 2004
    Location
    Norway
    Posts
    2

    Re: Rotating airplane

    That did the job! Thanks!

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