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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.
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
feedback output adjustment Elements of a Cybernetic System“The feedback Loop” Environment Sensor Comparator Activator • AC-unit-in-a-room example
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
Game state feedback Scoring function output adjustment Game Controller Game mechanical bias • Information known to all players • Information known to only one player • Information known to the game only • Randomly generated information Game state Feedback Loops in Games(Marc LeBlanc) Environment Sensor Comparator Activator
Example of negative Feedback: Downforce • Negative: • Simulated gravity vs. player • AI lets itself catch-up if you are loosing • AI catches up if you are winning http://www.youtube.com/watch?v=z-OQzqUdbs4 http://www.youtube.com/watch?v=37g5uNwmqz4
AI lets itself catch-up if you are loosing • Position of autos • Configuration of track • … feedback Game state Scoring function • Player position, leadingCar position • Formally: Distance(player,finish), Distance(leadingCar,finish) adjustment output Game mechanical bias Game Controller • Slow down leading-car • Formally: • speed(leadingCar) • speed(player) f(Distance(player, leadingCar) • Player loosing? Formally: • Distance(player, finish) > Distance(leadingCar, finish)
Simulated gravity vs player control • Position of autos • Configuration of track • speed… feedback Game state Scoring function • Player direction • Road direction adjustment output Game mechanical bias Controller • Steer car towards road • Player going out of road?
Mortal Combat: combo • Health Points player • Health points opponent • Disabled (Yes, No) • Opponent situation (chance for next combo, no chance) Game state feedback Scoring function • Disabled, • Opponent situation adjustment output Controller Game mechanical bias • Disabled = Yes • Opponent situation = chance for next combo • Disabling attack
Difficulty LevelsBrigette 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) Examples? • 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!