Artificial Intelligence in Computer Games

Our goal is to create a working AI controlled player (AI CP) for a Real-Time Strategy (RTS) game. In any given computer game you have a specific environment with its own obstacles and problems that must be solved in order to implement a computer opponent.

From the perspective of the game AI developer, while there is indeed the desire to impress the player with the intelligence of the AI, in practice a lot of time will be spent on applying algorithms to solve practical problems, such as terrain analysis techniques, path planning and pathfinding, and following the rules of the game in terms of what can be built at a given time and where it can be built.

Computer Controlled Opponents in Single Player Mode

Most, if not all RTS games can be played in a single player mode where the player faces a computer opponent. Traditionally the behavior of the computer opponent was simple, such as having the computer opponent attack at intervals in small waves of units, putting a sense of action into the game. In most single player game situations in RTS, the human player starts with considerably less resources than the opponent. The purpose of the computer opponent is to provide enough resistance for the player to feel there is a purpose. Often the enemy has a predesigned base and a continuous production of units.

Single Player Mode and Artificial Intelligence

A goal in the development of an AI is to make the human player identify the computer opponent as an opposing player and not just a set of algorithms. One should remember that the most pressing requirement as far as the game developer is concerned is subjective user satisfaction. The development of a computer opponent for a game requires that most of the game engine has been completed, so AI development is often hurried towards the end of the process.

This is one of the reasons why traditionally RTS AI has been predictable using scripted behavior, since this is low cost and reliable. But there is also the desire to create computer opponents that show intelligence while providing challenging resistance.

AI Controlled Opponents in Multi Player Mode

Multi player games are generally for the purpose of competing and seeing who is the better player. The setting of the match is generally on even terms, so that the skill of the player is compared on a “fair” basis to that of a AI controlled opponent. Creating a computer controlled opponent which has sufficient skill to put up a good fight against a skilled player is difficult, so various means of tipping the scales are often used.

For instance, an AI opponent in WarCraft III multiplayer mode set to “hard” difficulty will receive twice as many resources as human players from all sources. Another trick benefitting computer opponents is having information about the players movements and units available at all times without having to travel to discover his position.

Differences Between Human Players and AI Controlled Players

Human players playing against the same AI opponent repeatedly will be able to learn and gain some understanding of how the AI is able to play in terms of strategy, and also how it plays in detail. Human players tend to specialize in particular ways of playing, and so the AI is likely to play similar from game to game against this player. The AI has to generally be robust in the ways of being able to beat different strategies, because if there are strategies it is unable to beat then it will certainly lose most games in the long run. The AI has to have a way of countering all imaginable strategies that the player can choose, because a player will experiment and try to find strategies that the AI can not counter, if there are any.

A human player is able to scout in the game, by sending units to places he suspects there might be enemies and possibly discovering their location and what they are doing. He also knows the settings for the game which determined the possible starting locations, and so he can scout those locations to be reasonably sure to find enemy units. It is also common to be able to guess which route the enemy is most likely to attack via. As a human players plays the game, he gains experience about what strategies are common under given game settings, and so he will effort to make safeguards against those strategies. It is possible for an AI to achieve some of these qualities through learning, which requires a training period for the AI to gather and analyze data.

4.2 Make up ten questions to the report you’ve listened to.

4.3. Discuss the report using the following words and phrases. Work in pairs.

Could you, please, …

Could you be so kind…

One moment, please.

Just a moment/second, please.

Just let me finish.

This won’t take more than a few seconds.

Go ahead. Not at all.

I am surprised you did not know it already.

I was pleasantly surprised that…

It is surprising that…

I’m sure that…

I’m certain that…

I’m convinced that…

I really do think that…

I’m absolutely convinced that…

I’m confident that…

Do you feel sure about it?

Well, let me see…

Oh, let me think for a moment…

Well…

I’m not quite sure.

I wish I was as confident as you are.

You are sure of that, aren’t you?

I can’t be sure that…

In my opinion…

My point of view is…

If you ask me…

As I see it…

The point is…

As for my part…

As far as I’m concerned…

I think (suppose, guess, believe, dare say)…

I consider…

I wouldn’t say that…

On the one hand…

On the other hand…

I would like to say that…

The point is that…

I think we have to consider that…

I think I should mention here that…

We should always remember that…

I’m sorry, I don’t quite get your point…

Would you mind getting over that again?

Could you expand on that point?

What are you getting at?

Can you tell me something about…?

What is your position to…?

Can you give us some information about…?

What I’d like to know is…

4.4. Imagine that you are a member of a conference, devoted to the topic “Artificial Intelligence in Computer Games”. Use linking words and the conversational phrases given above to express your point of view.

4.5 Think over an outline of your speech at the scientific conference devoted to the question of Intelligent information systems. You should choose a problem that you are interested in and prepare your speech.

4.6 Take part in a role play “Participating in a scientific conference about intelligent information systems”, using phrases giving above.

Card A	Card B
You are a member of the scientific conference. Give your own opinion on this problem.	You are a chairman of the conference. Specify the point of view of the conference member.