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AI and GAMES
CSC 8520, Villanova University
Spring, 2004
Paula Matuszek & Robin McEntire
Some games to explore
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Yahoo AI Games directory. Mostly chatbots;
20 questions is good.
Yahoo Artificial Life . I like Insaniquarium.
Chinook. The world man-machine champion
checkers player.
A Mastermind variant.
Othello (Reversi). One of the classic neural
net testbeds.
Battleship (Armada).
The entire Yahoo web games directory can
be fun to explore. Which of these seem to
have an AI component?
GAMES and AI
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Most of these games are using AI. Here
are some discussion points:
Agents: which of these games have
autonomous agents? What’s the PEAS
description?
What AI techniques are being used?
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A* search (eg, for path finding)
Alpha-Beta search (eg, for choosing a move)
Knowledge representation
Natural language processing
Artificial life and flocking/swarming
Reasoning
Learning
Insaniquarium
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Agents with PEAS?
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Performance measure
Environment
Actuators
Sensors
Search?
Knowledge Representation?
Natural Language processing?
Logic and inference?
Other?
Chinook
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Agents with PEAS?
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Performance measure
Environment
Actuators
Sensors
Search?
Knowledge Representation?
Natural Language processing?
Logic and inference?
Other?
Battleship
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Agents with PEAS?
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Performance measure
Environment
Actuators
Sensors
Search?
Knowledge Representation?
Natural Language processing?
Logic and inference?
Other?
Mastermind
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Agents with PEAS?
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Performance measure
Environment
Actuators
Sensors
Search?
Knowledge Representation?
Natural Language processing?
Logic and inference?
Other?
Role Playing Games: Non-Player
Characters (Helpers, Opponents)
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Agents with PEAS?
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Performance measure
Environment
Actuators
Sensors
Search?
Knowledge Representation?
Natural Language processing?
Logic and inference?
Other?
Summary
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Even very basic AI can contribute to
games in a variety of ways.
Most important single AI technique for
gaming? Probably A*.
AI can provide opponents, partners,
support characters, story directors,
commentators.
AI and artificial life are fun. ALife
doesn’t have to be Turing-test level of
intelligence for good gaming.
From a GAME perspective
There are two fields that are relevant here
 AI:
– AI has techniques to contribute to games.
– Games are a fertile field for AI research.
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Games:
– Gaming has enormous market importance.
– Games are growing increasingly sophisticated
in all dimensions
– A game has to be fun; use whatever AI
techniques aid that.
Game Design, Game AI
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Background: Game Genres
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Racing – other cars
Action – enemies, allies
Real Time Strategy (RTS) –units,
commanders (for both sides)
Role Playing Games (RPG) – monsters,
party members, Non Player Characters
Sports – players, coaches,
commentators
Shooter – targets, more targets
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Obvious Examples of AI
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Car Game – write a virtual driver
Shooter – write a virtual player
Sports Games – write a virtual coach
RTS – write a virtual general
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Mini Case Study:
Racing Game History
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No “AI” cars, only real players are
drivers
“AI” cars which follow scripted path
Follow path, adjust speed
Feedback system to follow path
“Rubber band” near player
Attempt to have driver “personality”
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Somewhat Real Examples
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Car Game – write AI to keep races
close
Shooter – enemies die lots, win little
Sports – commentators, help player
RTS – generals who work on pacing
It is A Question of Design Purpose
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Game Development
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What is the goal for Player
Experience?
How is the AI going to further that
goal?
Role of the designer
Role of the programmer
How “design” evolves
Constraints
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Roles of a Game AI
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Tool for the designer
Foil for the player, creates opportunity
Dynamic challenge
Events: Emulation v. Simulation
Assists in Driving the action
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Shipping Games vs. Test Code
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Hard constraint on CPU usage
Reproducibility is vital, for test and
design
Must be fun, not correct
Must succeed, finish, do something,
always
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Mini Case Study
The Thief AI
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Design Goals
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Player is going to be a Thief
i.e. Sneak Around, Ambush, Hide, Steal
– AI must allow players to make plans
– And react to player actions, provide
challenge
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Game will feature a loose overall story
– Ability to script/override behavior
– In-game actions fed back out to story
control
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
“Watch-able” by the player
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Has to “go about it’s business” with
intent
Actions must make sense to player
– “interestingly predictable”
– present play opportunities for player
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Overemphasize thoughts
– Telegraph all actions
– Goals must be very explicit
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Implementation
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Model senses, detection, awareness
Simple event based “reaction” scripts
Tagging of world objects which notify
AI
Patrol paths, dynamic “go-to-object”
Rule based match database for speech
Heavily designer driven, toolset
approach
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Requirements
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Focus on the Player Experience
Allow player to understand AI actions
Needs to achieve design aim (and fun)
Configurable, Override-able, Testable
Satisfies data and speed constraints
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt
Themes
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Player Player Player Player Player
Player
How can AI enhance player experience
AI is facilitator of the “fun”
Enable creative expression for player
– Allow player to impact the world
– Put player in interesting situations
Based on:
Doug Church, October, 2001: ai.eecs.umich.edu/people/laird/game-seminar/Doug-Church.ppt