Paper: Map-Adaptive Artificial Intelligence for Video Games

Map-Adaptive Artificial Intelligence for Video Games

[Laurens van der Blom, 2007]

The author of this paper explains how to implement an AI opponent in a RTS game that takes into account the properties of the map it is placed in. For example, the AI makes decisions based on the amount of resources nerby, the location of cliffs and/or narrow passages, and the overall strategy of the opponent (if the opponent is playing offensively or defensively).

To achieve this, a ID3 Decision Tree was used in combination with fuzzy logic to allow the AI to find the best course of action depending on the current state of the game.

The game in which the AI was tested was a moderately complex RTS so the following set of rules were used:

1. Construct metal extractors at near metal resources.
2. Construct metal extractors at far away metal resources.
3. Place offensive units at relatively narrow roads.
4. Place offensive units at own base.
5. Place artillery on cliffs.
6. Protect operational metal extractors.
7. Protect artillery on cliffs.

The AI was tested against a computer controlled opponent and a human opponent in five different types of maps designed to test specific attributes like amount of resources or presence of narrow paths. In most of their tests, the AI performed as they expected but when placed against a human player it lost most of the games (even if it also performed as expected).

What I liked about this approach is that the AI actually varies the strategy if the enemy is near or not and if the enemy is attacking or not and it's relatively easy to distinguish what actions are being performed by it. And while this approach works, the AI had a hard time beating human players. That may be caused because, as the author states in the article, the decision tree needed more specific cases. Maybe the use of a nerual network could remedy this issue, but it could make the implementation a little more complicated or even change it completely.

Read article, complete with experiments and results here.

Van der Blom, Laurens, 2007. Map-Adaptive Artificial Intelligence for Video Games. Obtained in July 21st, 2011. http://www.unimaas.nl/games/files/bsc/Blom_BSc-paper.pdf