public virtual void RotateVelocity(
	int FirstState,
	int StateCount
)

FirstState must represent the sprite in a rightward-aiming state, and each subsequent state must represent an equal counter-clockwise rotation until StateCount states result in the sprite pointing almost rightward again. The sprite's current state must be one of the states in that range. This function is useful for car-type sprites where turning the sprite should automatically cause the sprite to be moving in that direction only (no drifting in the previous direction like a space ship would).