Gesture touch controls have become increasingly popular with the presence of mobile touchscreen devices, and even though there aren't any gestures built in to the OUYA SDK, the idea behind them is simple enough that we can code a solution ourselves.
Essentially, every touch gesture has a start point, an end point, and a speed at which the player's finger moves between them. In this section, we'll create variables for this data and create a function that fires a cannonball with a speed and angle based on a touch gesture.