Calling the shots

Hi there,
I'm trying to find the origin of the expression "calling the shots", meaning the boss or the one in control.
My first thought assumed the origin to be a movie director directing scenes or "shots"; but it may just as likely refer to a talented 8 Ball or pool player nominating his next "shot"; or perhaps even a bartender controlling the number of "shots" a patron is allowed.
Any info would be appreciated!
Many thanks,
Altec

I always thought it was from the game of pool aka pocket billiards where the shooter calls his shot ie is going to sink the 6 ball in the side pocket.