Provided by: allegro4-doc_4.4.3.1-4.1build3_all 

NAME
quat_slerp - Version of quat_interpolate() allowing control over the rotation. Allegro game programming
library.
SYNOPSIS
#include <allegro.h>
void quat_slerp(const QUAT *from, const QUAT *to, float t, QUAT *out, int how);
DESCRIPTION
The same as quat_interpolate(), but allows more control over how the rotation is done. The how parameter
can be any one of the values:
QUAT_SHORT - like quat_interpolate(), use shortest path
QUAT_LONG - rotation will be greater than 180 degrees
QUAT_CW - rotate clockwise when viewed from above
QUAT_CCW - rotate counterclockwise when viewed from above
QUAT_USER - the quaternions are interpolated exactly as
given
Allegro version 4.4.3 quat_slerp(3alleg4)