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