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How to?

Started by HellRiZZer Feb 27, 2003 at 7:31 PM 5 replies 500+ views
Fantasio
Fantasio
first, Rotation(x,y,z) is useless. you will never need of that.
and scale is the [0][0] [1][1] [2][2] of the matrix and these element of teh matrix is a part of the rotation matrix.
Fantasio
Fantasio
I never needed to do that, but... I think if you convert your matrix in quaternion, you will be able to get what you want.
A quaternion represents an axis in 3-D space and a rotation around that axis.



          
VOID QuaternionFromMatrix( FLOAT& x, FLOAT& y, FLOAT& z, FLOAT& w,
                                   D3DMATRIX& mat )
{
    if( mat._11 + mat._22 + mat._33 > 0.0f )
    {
        FLOAT s = sqrtf( mat._11 + mat._22 + mat._33 + mat._44 );

        x = (mat._23-mat._32) / (2*s);
        y = (mat._31-mat._13) / (2*s);
        z = (mat._12-mat._21) / (2*s);
        w = 0.5f * s;
    }
}



[edited by - fantasio on February 27, 2003 12:11:34 AM]
Fantasio
Fantasio
What do you want to do with angles?
you will probably need to compute a matrix with your angle and apply the Matrix to some vectors.
SantaClaws
SantaClaws
OpenGL''s matrices are 4x4, and in column order:

[ 0 4  8 12 ]
[ 1 5  9 13 ]
[ 2 6 10 14 ]
[ 3 7 11 15 ]


(0, 1, 2) is the normal pointing right.
(4, 5, 6) is the normal pointing up.
(8, 9, 10) is the normal pointing forward.
(12, 13, 14) is the translation.

At least, IIRC.

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