## vec_rotate (VECTOR* vDir, ANGLE* vAng)

Rotates a direction vector by pan, tilt and **roll** Euler angle.
## vec_rotateback (VECTOR* vDir, ANGLE* vAng)

Inverse rotation: rotates a direction vector that was rotated by an Euler angle back to its original orientation ( A7.08 ).
## vec_rotateaxis (VECTOR* vDir,VECTOR* vAxis,var angle)

Quaternion rotation: rotates a direction vector by an angle about a given rotation axis ( A7.08 ).
### Parameters:

**vDir** |
Pointer to a direction vector that is rotated. |

**vAng** |
Pointer to an Euler angle vector. Only the **pan** and **tilt** components are used. |

**vAxis** |
Pointer to a direction vector that serves as rotation axis. |

**angle** |
Rotation about **vAxis** in 0..360 degrees counterclockwise. |

###
Returns:

**vDir**

### Modifies:

**vDir**

### Speed:

Fast**
**Remarks:

**
**A position can be rotated around a center by subtracting the center vector from the position, rotating the result, and then adding the center vector again.
### Example:

var direction[3] = { 10, 0, 0 }; *// vector of length 10, pointing straight eastwards in the XYZ coordinate system*
var angle[3] = { 90, 45, 0 }; * // pan 90 degrees, tilt 45 degrees*
...
vec_rotate(direction,angle);

The direction
vector now has the new values 0, 7.07, 7.07. It was rotated by 90 degrees counterclockwise
and tilted by 45 degrees upwards, so it now points to the north and halfway
upwards.

### See also:

**
**Vectors, ** **angles, ang_add, vec_to_angle, vec_for_angle
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