Now that Box2D is introduced with a basic project, let's focus on the real one. We will modify our basic Tetris to get Gravity-Tetris alias Gravitris. The game control will be the same as in Tetris, but the game engine will not be. We will replace the board with a real physical engine.

With this project, we will reuse a lot of work previously done. As already said, the goal of some of our classes is to be reusable in any game using SFML. Here, this will be made without any difficulties as you will see. The classes concerned are those you deal with user event Action, ActionMap, ActionTarget—but also Configuration and ResourceManager. Because all these classes have already been explained in detail in the previous chapters, I will not waste time to explain them again in this one.

There are still some changes that will occur in the Configuration class, more precisely, in the enums and initialization methods of this class because we don't use the exact same sounds and events...