Later in this chapter, we'll develop and test an IL algorithm called DAgger on a new environment. The environment named Flappy Bird emulates the famous Flappy Bird game. Here, our mission is to give you the tools needed to implement code using this environment, starting from the explanation of the interface.

Flappy Bird belongs to the PyGame Learning Environment (PLE), a set of environments that mimic the Arcade Learning Environment (ALE) interface. This is similar to the Gym interface, and later we'll see the differences, although it's simple to use.

The goal of Flappy Bird is to make the bird fly through vertical pipes without hitting them. It is controlled by only one action that makes it flap its wings. If it doesn't fly, it progresses in a decreasing trajectory determined by gravity. A screenshot of the environment is shown here: