Before we can even begin to think about our project, we need to review the basics of Box2D. There is a lot of depth to the Box2D engine, and we will only be scratching the surface in this book. This section aims to give an overview of the parts of the engine that we will need to interact with for this game.
To quote the manual, "Box2D is a 2D rigid body simulation library for games. Programmers can use it in their games to make objects move in believable ways and make the game world more interactive." That's a pretty straightforward description of what Box2D is, except for the "rigid body" term. What does that mean? Rigid body means that Box2D is built to simulate hard objects such as balls, walls, stone, metal, and so on. Box2D was not built to simulate "soft body" objects such as pillows, jelly, and so on.
We will briefly go through the basic terms of the Box2D environment here, and we will deal with everything in more detail when we build the game. The...