Hands-On Artificial Intelligence with Unreal Engine

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AI in games

The history of AI in video games is as interesting as what we talked about in the previous section. We don't have the time to go through it in detail and analyze every single game and how each one of them contributed to the field. For the most curious of you, toward the end of this book, you will find other lectures, videos, and books where you can dive deeper into the history of AI in games.

The first form of AI in video games was rudimental and used in games like Pong [Atari, 1972], Space Invaders [Midway Games West, Inc., 1978], and so on. In fact, beyond moving a paddle to try and catch a ball, or moving aliens toward the player, there wasn't much more we could do:

A screenshot of Space Invaders Midway Games West, Inc., 1978], in which a rudimental form of AI is used to control the aliens

The first renowned game that used a noticeable AI was Pac-Man [Midway Games West, Inc., 1979]. The four monsters (later named ghosts due to a flickering port in the Atari 2600) used an FSM to chase (or flee from) the player:

A screenshot from the game Pac-Man Midway Games West, Inc., 1979], in which the four monsters use an FSM trying to catch the player

During the 1980s, AI in games didn't change much. It was only with the introduction of Warcraft: Orcs & Humans [Blizzard Entertainment, 1994] that a pathfinding system was successfully implemented in a video game. We will explore the Navigation system in Unreal in Chapter 3, Navigation:

A screenshot from Warcraft: Orcs Humans Blizzard Entertainment, 1994], in which the units (orc peons and grunts in this screenshot) use pathfinding algorithms to move in the map

The game that probably started to sensitize people about AI was Goldeneye 007 [Rare Ltd., 1997], which showed how AI could improve gameplay. Although it was still relying on FSMs, the innovation was that characters could see each other, and act accordingly. We will explore agent-awareness in Chapter 5, Agent Awareness. This was a hot topic at the time, and some games made it the main game mechanic, such as Thief: The Dark Project [Looking Glass Studios, Inc., 1998]:

A screenshot from Goldeneye 007 Rare Ltd., 1997], which has changed how people perceive AI in video games

and Metal Gear Solid [ Konami Corporation , 1998]:

A screenshot from Metal Gear Solid [ Konami Corporation, 1998],

Another hot topic was modeling a soldiers' emotions during battles. One of the first games that implemented an emotional model was Warhammer: Dark Omen [Mindscape, 1998], but it was only with Shogun: Total War [The Creative Assembly, 2000] that these models were used with extreme success with a large number of soldiers without performance issues:

A screenshot from Warhammer: Dark Omen, one of the first games that used an emotional model for soldiers

and

A screenshot from Shogun: Total War. The emotional model of the soldiers were more sophisticated than the one in Warhammer: Dark Omen, and yet it was used successfully with many soldiers

Some games even made AI the core of the gameplay. Although one of the first games to do so was Creatures [Cyberlife Technology Ltd., 1997], the concept is more evident in games like The Sims [Maxis Software, Inc., 2000] or Black and White [Lionhead Studios Ltd., 2001]:

A screenshot from The Sims. A Sim (the character) is cooking, which is part of a complex behavior piloted by AI in the game.

In the last 20 years, many AI techniques have been adopted and/or developed. However, if the game doesn't require an advanced AI, you will probably find FSMs, still being broadly used, along with Behavior trees, which we will start exploring soon in Chapter 2, Behavior Trees and Blackboards.