I'm trying to get the y-axis rotation from a matrix.
I found this:
...but I don't know if that's for D3D9 matrices. It's tricky because of the return values of atan2 as well.
I looked at D3DXMatrixDecompose() but I don't know how to get the y-axis rotation from the quaternion.
I'm hoping to get the rotation in [0...twoPi]