AdministrativeSlide 2CyberneticsElements of a Cybernetic System “The feedback Loop”Kinds of FeedbackSimple Cybernetic DesignExample of “this stuff” in games?Feedback Loops in Games (Marc LeBlanc)Example of negative Feedback: DownforceAI lets itself catch-up if you are loosingSimulated gravity vs player controlMortal Combat: comboDifficulty Levels Brigette SwanDynamic Difficulty Adjustment (DDA) -- The Oblivion ControversyUse of Feedback in Games (Marc LeBlanc)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-adjustmentElements of a Cybernetic System“The feedback Loop”EnvironmentComparatorSensorActivator• AC-unit-in-a-room example feedbackadjustmentoutputKinds 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 heaterSimple 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 beforeExample of “this stuff” in games?•Positive/negative feedback in games?–An example of positive feedback–An example of negative feedbackFeedback Loops in Games(Marc LeBlanc)EnvironmentComparatorSensorActivatorfeedbackadjustmentoutputGame stateGame mechanical biasScoring functionGame ControllerGame state Information known to all playersInformation known to only one playerInformation known to the game onlyRandomly generated informationExample of negative Feedback: Downforcehttp://www.youtube.com/watch?v=37g5uNwmqz4http://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 winningAI lets itself catch-up if you are loosingfeedbackadjustmentoutputGame stateGame mechanical biasScoring functionGame 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 controlfeedbackadjustmentoutputGame stateGame mechanical biasScoring functionController•Position of autos•Configuration of track•speed…•Player going out of road? •Player direction•Road direction•Steer car towards roadMortal Combat: combofeedbackadjustmentoutputGame stateGame mechanical biasScoring functionController•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 attackDifficulty 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