D3DXQuaternionLn function (D3dx9math.h)

Note

The D3DX utility library is deprecated. We recommend that you use DirectXMath instead.

Calculates the natural logarithm.

Syntax

D3DXQUATERNION* D3DXQuaternionLn(
  _Inout_       D3DXQUATERNION *pOut,
  _In_    const D3DXQUATERNION *pQ
);

Parameters

pOut [in, out]

Type: D3DXQUATERNION*

Pointer to the D3DXQUATERNION structure that is the result of the operation.

pQ [in]

Type: const D3DXQUATERNION*

Pointer to the source D3DXQUATERNION structure.

Return value

Type: D3DXQUATERNION*

Pointer to a D3DXQUATERNION structure that is the natural logarithm.

Remarks

The D3DXQuaternionLn function works only for unit quaternions.

A unit quaternion, is defined by:
Q == (cos(theta), sin(theta) * v) where |v| = 1
The natural logarithm of Q is, ln(Q) = (0, theta * v)

The return value for this function is the same value returned in the pOut parameter. In this way, the D3DXQuaternionLn function can be used as a parameter for another function.

Use D3DXQuaternionNormalize for any quaternion input that is not already normalized.

Requirements

Requirement Value
Header
D3dx9math.h
Library
D3dx9.lib

See also

Math Functions

D3DXQuaternionExp

D3DXQuaternionSquad