AI for Game Developers

Chapter 15. Genetic Algorithms

It is the game designer’s job to create a challenging game environment for the player. In fact, a large part of game development involves balancing the game world. It needs to be challenging enough for the players, or the game will seem too easy and they will lose interest. On the other hand, if it’s too difficult, the players will become frustrated. Sometimes players can discover loopholes, or exploits, with which they essentially can cheat. This can be a result of a game design issue that the developers simply overlooked. Another game design problem stems from the fact that the skill levels of different players can vary greatly. Creating a truly balanced and challenging game for players of different skill levels can be a daunting task. Fortunately, genetic algorithms can help.

In this chapter, we are not going to attempt to model a true genetic system. A true genetic model probably wouldn’t be practical or beneficial in a real computer game. Instead, the system we are going to discuss is merely inspired by a biological genetic system. In some ways it will be similar, but we won’t hesitate to bend the rules if it benefits the game design process.

In the real world, species constantly evolve in an attempt to better adapt to their environments. Those that are most fit continue to survive. Charles Darwin proposed this phenomenon in 1859 in his famous work entitled “On the Origin of Species.” Those that are most able to survive in their environments are ...