Game AI versus AI: An Introduction to AI Game Programming

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Game AI versus AI An Introduction to AI Game
Programming

• Héctor Muñoz-Avila

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Game AI
Do you know what is attack Kung-Fu style?
http//www.youtube.com/watch?v5q9kYKtvYU0
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Half-Life Gordon Freemans First Encounter with
the Marines
Do they attack Kung-Fu style?
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Half-Life Kung-Fu Attack

• Actually no more than 2 marines are attacking at
  any time
• The other marines take cover, move around etc.
• When one of the attacking marines run out of
  ammo, is wounded, dies, etc., one of the others
  take his place

• Some reactions are hard-coded and
  scenario-dependent

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Game AI

• Term refers to the algorithms controlling
• The computer-controlled units/opponents
• Gaming conditions (e.g., weather)
• Path finding
• Attack Kung-Fu style is an example of game AI for
  the computer opponent
• Programming intentional mistakes is also part of
  controlling the computer opponent AI

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Programming Good AI Opponent(according to Lars
Liden Ch. 2 AIWS1)

• Enemies move before firing
• Make mob/enemy visible
• Announce enemy presence by sound or other means

http//www.youtube.com/watch?vvL8YfqyU4Fofeature
related
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Programming Good AI Opponent (II)(according to
Lars Liden Ch. 2)

• Have horrible aim (rather than doing less damage)
• Miss the first time
• Warn the player (e.g., music, sound)
• Kung-Fu attacks

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What is AI?
Categories for definitions of AI
Systems that think like humans Systems that think rationally
Systems that act like humans Systems that act rationally
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The Turing Test Preliminaries

• Designed by Alan Turing (1950)
• The Turing test provides a satisfactory
  operational definition of AI
• Its a behavioral test (i.e., test if a system
  acts like a human)
• Problem it is difficult to make a mathematical
  analysis of it

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The Turing Test
The Turing Test a computer is programmed well
enough to have a conversation with an
interrogator (for example through a computer
terminal) and passes the test if the interrogator
cannot discern if there is a computer or a human
at the other end
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The Turing Test vs. AI Fields
For a program to pass the Turing Test, it needs
to pass the exhibit the following capabilities

• Natural language processing
• Knowledge representation
• Automated reasoning
• Machine learning

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Loebner Prize

• Each year (since 1994) a competition is made to
  see if a computer passes the Turing Test
• The first program to pass it will receive 100k
• Controversial Minsky offer 100 if anyone finish
  it
• Still, it is interesting to observe capabilities
• Machines seems to have come close to fulfill
  Turings prediction (5 minutes)

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Loebner Prize (II)
ENTRANT Welcome judge 4JUDGE Hello. What's the
weather outside?ENTRANT I haven't been outside
much today. I am fond of asparagus myself.JUDGE
How old are you?ENTRANT I'm about 30.JUDGE
About?ENTRANT I can talk about Star
Trek.JUDGE No let's talk about you. Exactly how
old are you?ENTRANT Right you are batman.
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Other Predictions from Turing

• Predicted that by the year 2000 a computer will
  have 30 chances to fool a person for 5 minutes
• Anticipated the major arguments against AI
• The mathematical objection to AI
• Argument from Informality

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The Mathematical Objection to AIThe Halting
Problem

• Can we write a program in a language L (i.e.,
  java), that recognizes if any program written in
  that language ends with a given input?

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The Mathematical Objection to AI

• Argument against AI a human can determine if a
  program ends or not
• Thus, computers machines are inferior as humans

• Argument against this argument
• If the brain is a deterministic device then it is
  a formal system like a computer is (though more
  complicated)
• If the brain has some non deterministic aspects,
  then we can incorporate devices that has non
  deterministic behavior

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Point of View in Our Course

• These discussions refer to pros and cons of
  constructing a machine that behaves like a human
• A wide range of techniques have been developed as
  a result of the interest in AI
• In practice, some of these techniques have been
  effectively used to enhance computer games
• Studying these successfully applied techniques
  for games and promising directions is one of the
  two aspects to be covered in this course
• (the other aspect to be covered in this course
  is how Game AI is created nowadays)
• We leave the discussion of whether a Game exhibit
  a human-like behavior or not to cognitive
  scientist or philosophers

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AI Genesis

• Logical reasoning calculus was conceived
  (Leibniz, 17 century)
• Leibiz motivation solve intellectual arguments
  by calculation
• Boolean logic (Boole, 1847)
• Predicate Logic (Frege, 1879) Begriffsschrift
• Incompleteness Theorem (Goedel, 1940s)

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AI Some Historical Highlights

• Turings article about what machines can do
• Term AI is coined at the Dartmouth conference
  (1956)
• General Problem Solver (Newell Simon 1958)
• Period of great expectations

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Early Stages, Great Expectations(what they
thought they could achieve)
Jenna What were you just thinking? Data In
that particular moment, I was reconfiguring the
warp field parameters, analyzing the collected
works of Charles Dickens, calculating the maximum
pressure I could safely apply to your lips,
considering a new food supplement for Spot...
Jenna I'm glad I was in there somewhere.
(from In Theory episode)
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AI Some Historical Highlights (contd)

• Perceptrons limits to neural networks (Minksy
  and Papert 1969)
• Knowledge-based systems (1970s)
• AI becomes an industry. Early successes of Expert
  systems

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AI Some Historical Highlights (contd)

• It becomes clear that expert systems are hard to
  create (problem known as the Knowledge
  Acquisition bottle-neck)
• Renaissance of neural networks as connectionism
• 1990s more consolidated approaches to AI, more
  realistic expectations, fielded applications
• Applications of machine learning to data-mining
• Applications of various AI techniques to computer
  games

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Course Goal
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Some AI Topics
Some of which have been applied in commercial
computer games

• Search
• Planning
• Natural language processing
• Machine learning
• Case-based reasoning
• Robotics
• Computer vision
• Neural networks

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Game AI Topics

• (0) Pathfinding with the A algorithm (Joseph
  Siefers)(1) Squad tactics (Bryan Auslander)(2)
  Scripting languages (Karneeb, Justin T)(3)
  Real-Time Strategy games (Dave Heefner)(4)
  General Pathfinding tables and navigation
  (Jeremy David Christman)(5) Finite State
  Machines in Games (Stanislav Tsanev)(6) First
  Person Shooters (Xavier Otero Keil)(7) Racing
  games (Emily Cohen)(8) Role Playing Games (Nick
  Moukhine)(9) Story line, drama (Brander, Gregory
  M,)(10) Sports Games (Chris Wojciechowski)(11)
  General Pathfinding waypoints (Sarunac,
  Alexandar D.)(12) Individual NPC behavior
  (Jonathan Michael Ziegler)(13) Achieving gaming
  goals (Kellen J. Gillespie)(14) Player Modeling
  (Jim Morrison)(15) Crowd/swarm simulations
  (Kristen Gardner)(16) Camera control
  (Christopher M. Hinkey)(17) Map, World, Wall
  generation  (Mercer, Jonathan C.)(18) TBS (Matt
  Dilts)