Games and AI Jonas Lind Game Designer ITU, September, 2005

Introduction Io Interactive Hitman 1-3. Freedom Fighters Under production: – Hitman 4 – Other

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

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

Hitman through the ages

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

Team Structure

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

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

The State Machine States: Normal, Suspicious, Agg/Panic, Kissing Events: Objectvisible, Projectile_hit, KissMeNow

Scenario 1 Guard and maid standing in hallway. The begin kissing. Hitman comes into the hallway. Draws a gun and start shooting.

Scenario 1, State machine Normal Kissing Normal Kissing Suspicious Panic Aggre. Pretty Maid BodyGuard KissMeNow Objectvisible(hitman) Projectile_hit

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 nearby closet.

Scenario 2, State machine Patrol Sus(HeardOddSound) Investigate FoundDeadBody(cook) CallAssistance Suspicious(lookforfakecook)

Basescripts Basefunc Animal Human Civilian Armed Guard Sniper CamGuard Redneck Dog Croc General Lee PornBoss

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

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

Bad Scenarios Step in Line. 10 guards inside a bunker. Hitman stands outside the single entrance/exit. Shoots Gun. Everybody in turn try to get out. Get shot as soon as they step outside. Running Man. Hitman runs past everyone, slow reaction time makes it possible. After the Bomb. Hitman does something irreversible, but due to our ”equilibrium”- Model, funny results arise.

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.

Any Questions?