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videos for before• swarm.flv (art. intelligence swarmites 1:20)• endorphin2.5.flv (2:38)• antfarmsimulator.flv (3:30)• for very early– swarmflocking.mp4 (Suzie swarmites 2:36)– andiland.mp4 (5:04 min)

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Warning -This presentation contains

graphic depictions of violence and the death of

badly pixelated Nazis

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Hans Apfël• Born Dec 18, 1923,

Dusseldorf• Wanted to study chemistry

after the war• Engaged to Elsa Bauer

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Hans Apfël• Killed by a Super Terror

Flamethrower on level 7 of Nazi Killer Rampage IV.

• One of over 143,000,000,000,000 NPC's killed in computer games since 1959

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Ground Rules• The topic is game AI• It's not 'real' AI• Their morality is a separate discussion• I'll take questions as they come up• Please hold side topics to the end

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Game AI

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Sections

•Goals•Architecture• Inputs•Actions•Action Selection

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Vocabulary• NPC• Game Design• Third Person shooter• RTS

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Our Example• The Saboteur start up screen

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Roundup

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GOAL?

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PLAYER FUNnot to win!

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Fun IsMeaningful

ChoicesAppealing Characters

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And what's our best technique for adjusting

Play Balance?

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CHEAT

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Play Balance Knobs• Unit strength• Adjusting NPC tactics better/worse• Complexity, favor things the computer does

better than the human.• Cognitive and cockpit load, UI design,

behavior mod, degrade the human's skills

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Architecture

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Mimic Human Actions• Mimic the events the NPC would get• Stupid actions look inhuman• Sadly, stupid choices of action look all too

human• So as long as each low level action is

believable, overall we have a chance

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Our ArchitectureEvents

(as 'sensory' data)

Action Selection

Atomic Action Atomic Action Atomic Action

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Our ArchitectureEvents

(as 'sensory' data)

Action Selection

Atomic Action Atomic Action Atomic Action

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Model Their World View• Give NPC's only the info they should have,

then they won't act on info they shouldn't• Give them a view frustum• Present information as their sensory apparatus

would receive it.• Present information in functional terms (e.g. 'a

cover position', not 'a tree')

.

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Terrain Marking

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Our ArchitectureEvents

(as 'sensory' data)

Action Selection

Atomic Action Atomic Action Atomic Action

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Overview• Most action is – move the character's basepoint– play canned animations

• Some other possibilities– play sounds, particle effects, delete/add item, etc.

• Physics: ragdoll, euphoria, steering, lennard-jones• Middle layer– Pathfinding

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Basic Animation• Play one or more layered

animations• Move the basepoint• Do a whole motion!

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Behaviors

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Steering

AI boid

vehicleTurn

left at corner

wheel left 45

deg, light brake

position, rotation, velocity

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Lennard- Jones Potential

𝐹=𝑎𝑟2 −

𝑏𝑟 30 2 4 6 8 10 12

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

F vs R

F vs R

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A*• Open circles are in

open set• Filled circles are

colored red to green by distance from start

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Our ArchitectureEvents

(as 'sensory' data)

Action Selection

Atomic Action Atomic Action Atomic Action

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Action Selection

Behavior trees

Scripting

HFSM

Planners

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Scripting• Either use an existing 'friendly' language

(Python and Lua are popular) or make one up• Actor languages are often a good choice• burying complexity in message passing

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HFSM

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Planning• Operators: preconditions, forbidden, add,

remove• Operators: run_to_door, get_out_of_car,

enter_building, climb_stairs, descend_stairs, run_onto_roof, get_in_car, lay_down, get_up

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Complications

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Behavior Trees

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Node Types

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Adjusting Long Term Play• Genetic Algorithms• Neural nets• Random strategic alterations

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GOAL?

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PLAYER FUN