Controlling the game camera with SFML View

In my opinion, the SFML View class is one of the neatest classes. If after finishing this book you make games without using a media or gaming library, you will really notice the absence of View.

The View class allows us to consider our game as taking place in its own world, with its own properties. What do I mean? When we create a game, we are usually trying to create a virtual world. That virtual world rarely, if ever, is measured in pixels and rarely, if ever, will that world be exactly the same number of pixels as the player's monitor. We need a way to abstract the virtual world we are building, so that it can be whatever size or shape we like.

Another way to think of SFML View is as a camera through which the player views a part of our virtual world. Most games will have more than one camera or view of the world.

For example, consider a split screen game where two players can be in different parts of the same world, at different times.

Or consider...