Microsoft DirectX 8.1 (Visual Basic)

D3DXQuaternionLn

Calculates the natural logarithm.

D3DXQuaternionLn( _ 
    QOut As D3DQUATERNION, _ 
    Q As D3DQUATERNION)

QOut: D3DQUATERNION type that is the result of the operation, the natural logarithm.
Q: The source D3DQUATERNION type.

If the function fails, an error is raised and Err.Number can be set to one of the following values.

For information on trapping errors, see the Microsoft® Visual Basic® Error Handling topic.

This function works only for unit quaternions.

For a unit quaternion, Q == (cos(theta), sin(theta) * v)
The natural logarithm of Q is, ln(Q) = (0, theta * v)

The D3DXQuaternionSquadSetup method can also be used to set up the control points of a quaternion.