Administrative

• Next week (April 7th in class) the Design AnalysisProject is due  (this is required for all students andit is 15% of the final grade). If you have not done so,start working on it now.  We grade this project rigorously;particularly the level of effort put into the work.We expect that you will go the "extra mile" for thisproject and put a lot of effort into it.

• Next week (April 4th in class) is Test # 2. Covers all of Unit 2.

Games as Cybernetic Systems (Ch. 18)

Cybernetics• Resulted from Information Theory (Ch.

16) and Information Systems Theory (Ch. 17)

• Focus on how dynamic systems change over time

• Cybernetics is used to study organizations– Large companies– Governments

• Basic principle: output-feedback-adjustment

Elements of a Cybernetic System“The feedback Loop”

Environment

Comparator

Sensor

Activator

• AC-unit-in-a-room example

feedback

adjustmentoutput

Kinds of Feedback

• Example of each for the AC-unit-in-a-room example Negative: temperature(room) > 75 then activate cooler Positive: temperature(room) > 75 then activate heater

Simple Cybernetic Design

• Lets combine two feedback loops that maintains the temperature in a room stays between 65 and 75– We have a cooler and – We have a heater

• Lets do one that maintains the temperature in a room at 70. Same conditions as before

Example of “this stuff” in games?

• Positive/negative feedback in games?

– An example of positive feedback

– An example of negative feedback

Feedback Loops in Games(Marc LeBlanc)

Environment

Comparator

Sensor

Activator

feedback

adjustmentoutput

Game state

Game mechanical bias

Scoring function

Game Controller

Game state

Information known to all playersInformation known to only one playerInformation known to the game onlyRandomly generated information

Example of negative Feedback: Downforce

http://www.youtube.com/watch?v=37g5uNwmqz4 http://www.youtube.com/watch?v=z-OQzqUdbs4

• Negative:Simulated

gravity vs. player

AI lets itself catch-up if you are loosing

AI catches up if you are winning

AI lets itself catch-up if you are loosing

feedback

adjustmentoutput

Game state

Game mechanical bias

Scoring function

Game Controller

• Position of autos

• Configuration of track

• …

• Player loosing? Formally:

Distance(player, finish) > Distance(leadingCar, finish)

• Player position, leadingCar position

• Formally: Distance(player,finish), Distance(leadingCar,finish)

• Slow down leading-car

• Formally: speed(leadingCar) speed(player) f(Distance(player, leadingCar)

Simulated gravity vs player control

feedback

adjustmentoutput

Game state

Game mechanical bias

Scoring function

Controller

• Position of autos

• Configuration of track

• speed…

• Player going out of road?

• Player direction• Road direction

• Steer car towards road

Mortal Combat: combo

feedback

adjustmentoutput

Game state

Game mechanical bias

Scoring function

Controller

• Health Points player

• Health points opponent

• Disabled (Yes, No)

• Opponent situation (chance for next combo, no chance)

• Disabled = Yes• Opponent situation =

chance for next combo

• Disabled,• Opponent situation

• Disabling attack

Difficulty Levels Brigette Swan

• Adaptation to the quirks and habits of a particular player over time.

• Many games implement difficulty sliders.

• Common: – start early levels easy– More difficult as game

progresses– Difficulty can be amount

of information available!– Dynamic Difficulty

Adjustment (DDA)

Dynamic Difficulty Adjustment (DDA)-- The Oblivion Controversy

• Idea: adjust game so that it remains challenging (negative feedback)

• It is an RPG game like say Diablo but…

• As your avatar levels so do all mobs in the game – So for example you “clean” a dungeon at

level 1 killing some rats, at level 10 those rats will be armored and will hit much harder

• Does it still have meaningful play as a result?

Use of Feedback in Games (Marc LeBlanc)

• Stability:– Negative feedback stabilizes a game– Positive feedback destabilizes a game

• Game duration– Negative feedback can prolong a game – Positive feedback can end it

• Success:– Positive feedback magnifies early success– Negative feedback magnifies late ones

• Control:– Feedback systems can emerge from games– Feedback systems can take control away from gamers

… and result in lost of meaningful play!

Examples?