Compare - compare vectors element by element with optional tolerance. Equal - return TRUE if vectors are exactly equal. Length - compute length of a vector. Distance - compute distance between two points. DistanceSquared - compute the square of the distance between two points.
Quaternions are convenient alternatives to Matrices for storing rotations.
Concatenates quaternion rotations. Converts a quaternion into a rotation matrix. Since the roll angle is indeterminate, it is set to zero. Thanks to Kevin Thompson who kindly donated the original Quaternion code. Steve J. Baker.