Hi! I have object. User can free rotate it using LMouseButton. (rotation via arcball quaternions). Also there's ability object auto rotate (rotation around object z_axis on angle)
If user first rotates object by mouse, than turn on auto rotation - that's ok. but if first auto z-rotation and then free rotate - here not all right. in free rotation (1st case) - result quaternion = quaternion down(down mouse position) * quaternion rotation; it seems that in 2nd case i also need to multiply quaternions. But which quaternions and in what order?
