1. A method for controlling deployment of an airbag into a passenger compartment of a vehicle, comprising: detecting a position of an occupant whose forward-facing surface will be the surface which interacts with the airbag upon its deployment; determining a desired amount of gas within the airbag during inflation of the airbag based at least in part on the detected position of the occupant; and adjusting the amount of gas within the airbag during inflation of the airbag to provide the airbag with the desired amount of gas during its inflation.