D3DXQUATERNION structure (D3dx9math.h)
Note
The D3DX utility library is deprecated. We recommend that you use DirectXMath instead.
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)
C++ programmers can take advantage of operator overloading and type casting with the D3DXQUATERNION Extensions, which implement overloaded constructors and assignment, unary, and binary (including equality) operators.
Requirements
| Requirement | Value |
|---|---|
| Header |
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See also