games and ai jonas lind game designer itu, september, 2005

Games and AI

Games and AI

Jonas Lind

Game Designer

ITU, September, 2005

www.ioi.dk/~tj

Introduction

Io Interactive Hitman 1-3. Freedom Fighters Under production:

– Hitman 4– Other

www.ioi.dk/~tj

Overview

Introduction & overview What we do Process and Workflow The State Machine Scenarios Future improvements

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What we do

Character based FPS/3PS Noir and cartoony Key features Stealth (HM) and Squad(FF) Focus on Narrative HM -> Hardcore. FF -> Pick up and play PC, PS2, XBox

www.ioi.dk/~tj

Hitman through the ages

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Production Process

Idea stage (3 months)– Establishing graphical style– Gameplay sketch– Basic storyline

Prototyping/creating 1st demo (6)– Finishing design document– Contacting a publisher

Preproduction (6)– Maturing technology– Experimentation with gameplay and

UI

Production (10)– Content creation

(graphics, sound, scripts)

Crunch period (3)– Putting everything together– Fixing final errors– Quality assurance

Release (singularity)– Party + Sleep

Follow-up (3-6)– Patches– Press

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Team Structure

P rodu ction L in e - The Te am

P rodu ction coo rd ina tor

3 D m od e lling A n im a tion

Te xture a rt L e vel b uild ing

A u d io

L e ad de sign er

L e ve l se tup G a m e p la y se tup

A I scrip ting U se r inte rfa ce

E n gine

L e ad p rog ra m m er

E xtern a l P ro du cer

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Gameplay

Find the right combination of gameplay elements– Shooting and fighting (combat action)– Sneaking and hiding bodies (stealth)– Disguising by wearing enemy clothes (stealth)– Choosing the right weapons (planning)– Premission laptop briefings (planning)– Misc. small puzzles (thinking)

Construct levels by combining elements An iterative process of experimentation

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AI Philosophy

”Believability is the issue, not realism”

Cheating is allowed. Trade off: Speed vs. Depth (10% rule) Take advantage of human psychology Be Consistent

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The State Machine

States:

Normal, Suspicious, Agg/Panic, Kissing

Events:

Objectvisible, Projectile_hit, KissMeNow

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Scenario 1

Guard and maid standing in hallway.

The begin kissing. Hitman comes into the hallway.

Draws a gun and start shooting.

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Scenario 1, State machine

Normal Kissing Normal

Normal Kissing Suspicious

Panic

Aggre.

Pretty Maid

BodyGuard

KissMeNow Objectvisible(hitman) Projectile_hit

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Scenario 2

Cook stands and makes food in the kitchen. Outside kitchen a guard patrols. Hitman sneaks into kitchen takes a cutting knife and slit cooks throat, and hides in a nearbycloset.

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Scenario 2, State machine

Patrol

Sus(HeardOddSound)

Investigate

FoundDeadBody(cook)

CallAssistance

Suspicious(lookforfakecook)

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Basescripts

Basefunc

Animal Human

Civilian

Armed Guard

Sniper CamGuardRedneck

Dog Croc

General Lee

PornBoss

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Advantages

Powerful language, very versatile Clear structure Inheritance Event driven Cycle-efficient Allows for sound and animation handling

www.ioi.dk/~tj

Disadvantages

20% creation 80% damage control Endless tweaking because of customization Gameplay setup requires programming skills Slow iterative process Bottom of foodchain Bad Scenarios

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Bad Scenarios

Step in Line. 10 guards inside a bunker. Hitman stands outside the single entrance/exit. ShootsGun. Everybody in turn try to get out. Get shotas soon as they step outside.

Running Man. Hitman runs past everyone, slow reaction time makes it possible.

After the Bomb. Hitman does somethingirreversible, but due to our ”equilibrium”- Model, funny results arise.

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The next step?

Building block AI. for more simplistic gameplay.

Easier to test, faster to set up. Not as flexible.

Planning. Goal oriented. Pregeneration.

Dramaturgically interesting.

www.ioi.dk/~tj

Any Questions?