D3DXQUATERNION structure (D3DX10Math.h)

Describes a quaternion.

Syntax

typedef struct D3DXQUATERNION {
  FLOAT x;
  FLOAT y;
  FLOAT z;
  FLOAT w;
} D3DXQUATERNION, *LPD3DXQUATERNION;

Members

x

Type: FLOAT

The x-component.

y

Type: FLOAT

The y-component.

z

Type: FLOAT

The z-component.

w

Type: FLOAT

The w-component.

Remarks

Quaternions add a fourth element to the [ x, y, z] values that define a vector, resulting in arbitrary 4D vectors. However, the following illustrates how each element of a unit quaternion relates to an axis-angle rotation (where q represents a unit quaternion (x, y, z, w), axis is normalized, and theta is the desired CCW rotation about the axis):

q.x = sin(theta/2) * axis.x
q.y = sin(theta/2) * axis.y
q.z = sin(theta/2) * axis.z
q.w = cos(theta/2)

Requirements

See also

D3DX Structures