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Thread: Inverse Matrix

  1. #1
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    Inverse Matrix

    Hi, can anyone actually point out why, what and where the inverse matrix is used in openGL and why it is useful? thanks!
    ...People Who Say It Can't Be Done Are Passed By Those Who Are Doing It...

  2. #2
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    Re: Inverse Matrix

    you can use the inverse matrix M^-1 of matrix M when you want the changes that M did want to be undone.

    If you want another answer then please specify your question

  3. #3
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    Re: Inverse Matrix

    Ooh right thanks What about the determinant of a matrix, how is that useful in 3d graphics/games?
    ...People Who Say It Can't Be Done Are Passed By Those Who Are Doing It...

  4. #4
    Senior Member OpenGL Pro
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    Re: Inverse Matrix

    The determinant almost serves for calculating the inverse of a matrix.

  5. #5
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    Re: Inverse Matrix

    It is used to determine whether a polygon is backfacing.

  6. #6
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    Re: Inverse Matrix

    could you possibly explain how? The thoery behind it? If it's too lengthy explanation it doesn't matter
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  7. #7
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    Re: Inverse Matrix

    The explanation is a bit involved and it requires some knowledge of Linear Algebra.

    I won't get into all of that here but I can refer you to this
    should you care to read up on it.

  8. #8
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    Re: Inverse Matrix

    The inverse transformation matrix is necessary for vertex normal transformation.

    The vertex itself is multiplied with the modelview-projection-matrix. Normals need to be multiplied with the inverse transpose of that matrix to stay correct.
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