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7.1. OSCARS & ARTIFICIAL INTELLIGENCE
Interim awards and introduction to game AI
CSC2007 OSCARSMid-way awards
Submission with the most impressive/complex
exploratory codeSubmission with the best
progress to date
Category One
Category One: Honorary Mentions
Category One Honorary Mentions
oTeam members Game name
o
Category One Winners
oTeam membersTeam nameGame name
Most authentic rendition of a classic computer game
Most original/fun game design or game play idea
Game I least want to present at the Board of Examiners
Most comprehensive game design including development plan and
contingency planning.
Team/Game with the best name
Team/Game with the most inappropriate name
Category Two
Category Two WinnersCategory
Team membersTeam name – Game name
INTRODUCTION TO GAME AIIntroduction to game-oriented artificial intelligence
Artificial Intelligence (academic vs. game)
Artificial intelligence aims to develop machines that can perform human ‘thinking’ tasks.
Academic research is split into two camps:
• Strong AI – creating systems that model human thought processes
• Weak AI – creating working systems that need not be physiologically plausible
Academic AI tends to focus on optimal problem solving.
Game AI must work within tight computational constraints, i.e. effort vs. outcome is central.
The aims of game artificial intelligence
The aims of game-oriented AI can be summarised as follows. The AI must:
• appear intelligent, yet purposely flawed (i.e. beatable)
• have no unintended weaknesses (that can be repeatable exploited)
• provide an entertaining or engaging experience
• perform within tight CPU/memory constraints
• be configurable
• not keep the game from shipping
The illusion of intelligence…Most people assess intelligence (or the lack thereof) on how an object behaves.
Acting in a complex (human-like) manner is readily perceived as intelligence behaviour.
Aside: Describe the colour of
square A? What colour is B?
A is exactly the same colour as
B!
One means of enhancing game AI is to provide visual/auditory feedback on what the game object is ‘thinking.’
Often simple or semi-random behaviour will be perceived/intepretated by the player as complex/intelligent.
A practical definition of game AI“Game AI is anything that contributes to the perceived intelligence of an entity, regardless of what’s under the hood.”
Aside: Searle’s Chinese Room argument
Game AI (is it, or isn’t it)Which of the following could be classified as providing an example of AI within the context of a game?
• Does a single ‘if’ statement constitute intelligence?
• What about scripted behaviour?
• If an NPC selects which animation to play?
(If this is done via a set of if statements?)
• Maybe path-finding?
• If game automatically generates an environment?
GENRE SPECIFIC AIThe forms of AI found within different types of (2D) game
AI (in general)
AI needs within the game can include:
Perception – determining what can be seen (other opponents, pick-ups, incoming projectiles, etc.)
Steering – basic character movement
Action – executing available actions, e.g. aiming, shooting, etc.
Path-finding – movement route planning
Decision making – determining what to do next (dodge, seek health, ambush, etc.). At higher levels this becomes tactical AI.
Perception
Strategic AI
Decision Making
Steering
State Change
Line of sight tests
Influence maps
FSM
Kinematic movement
Object update
To do:
Consider
own
game
AI (side-on/top-down shooters)AI needs within the game can include:
Perception – detecting nearby objects, incoming projectiles, etc.
Steering – opponent movement, e.g. player tracking, projectile avoidance, etc.
Firing – basic control, firing towards player Perception
Steering
Shooting
State Change
Object detection
Path follow, Evade
Path projection
Object update
Aside: AI within 2D shooters may be
effectively nonexistent, i.e. relying on fixed
patterns of movement and opponent numbers
to provide challenge
AI (driving)AI needs within the game can include:
Perception – detecting other traffic
Steering – driving line, cornering, breaking
Decision making – overtaking points, collision avoidance
Perception
Decision Making
Steering
State Change
Predictive collision detection
FSM, Rule-based system
Path following
Object update
Aside: GTA/Driver clones would also include AI
routines to model other road traffic, etc.
AI (platform)AI needs within the game can include:
Perception – determining actions/movement of player
Steering – moving towards/away from player
Shooting – basic control, e.g. aiming
Perception
Steering
Shooting
State Change
Player proximity
Path follow, Pursue
Player proximity trigger
Object update
Aside: Platform games tend to have opponents which have predictable,
easily understood behaviour. Challenge
arises from the need to time jumps, shots, etc. to
overcome such opponents.
AI (real time / turn-based strategy)AI needs within the game can include:
Perception – determining what can be seen (other opponents, resources)
Steering – group movement, etc.
Path-finding – movement route planning
Tactical and Strategic Analysis – determining overall strategy build, attack, etc.
Perception
Strategic AI
Tactical AIDecision Making
Path finding / Steering
State Change
Opponent visibility, Fog-of-war
Tactical analysis, Influence maps
Rule-based system/ FSM
Map/local path-finding
Object update
Aside: AI in real-time games is mostly the same as in turn-based games. Real-time games must
impose tight performance constraints on the AI.
AI (beat-em-up)
AI needs within the game can include:
Decision making – determining what to do next (block, back-up, attack, etc.).
Decision Making
State Change
FSM / Rule-based behaviour
Object update
Aside: The behaviour can be adaptive, i.e. reacting to the player’s patterns of
behaviour
AI (sport)AI needs within the game can include:
Steering – basic character movement, group movement, etc.
Decision making – determining what to do next, selecting plays, formations, etc. from an available ‘playbook’
Tactical Analysis – determining play objectives
Tactical AI
Decision Making
Steering
State Change
Influence Maps
Rule-based system
Chase, Evade, etc.
Object update
Aside: Sport AI has the benefit of drawing upon
existing expert knowledge, but must return realistic, ‘human-like’ behaviour
Summary
To do:Think about the role
and needs of AI within
your game
Read about the Week 9
Alpha hand-in and plan
what you hope to
develop
Today we explored:
The role of AI within games and the constraints game AI must operate within
The typical roles of AI within 2D game genres