Creative Commons Attribution 3.0 creativecommons.org/licenses/by/3.0/ Interactivity & the Core Game Mechanic Foundations of Interactive Game Design Prof. Jim Whitehead February 6, 2008

Today’s Assignment Work Breakdown and Schedule ‣ Due Today Have exams and game concept documents ‣ Come up on stage after class to retrieve

Upcoming Assignments Busy week next week ‣ Partially Operational Game Prototype ❖ Due Friday, February 15 ❖ Need to have started your game ❖ Need to have at least some things working already ❖ Demonstration that you have spent at least 5-10 hours on your game already ‣ Progress Report ❖ Also due Friday, February 15 ❖ An update on where things stand in your schedule ❖ Is your project completing tasks on schedule, or falling behind?

Game Design Workshops Game Maker ‣ Wednesdays, 6-8pm ‣ Engineering 2, room 180 (Simularium) ❖ Enter on plaza level between E2 and JBE RPG Maker ‣ Wednesdays, 5-7:15pm ‣ Engineering 2, room 280 ❖ 2 nd floor, on front of building, on driving circle/Communications end (right side, east end) of the building ❖ Arrive by 6pm to avoid external doors locking ❖ Knock on nearest door if late… CS 20/C# and XNA Game Studio Express ‣ Thursdays, 4:30-7pm ‣ Engineering 2, room 399 (third floor, by elevators)

Interactivity What was the essential element of computer games that made them so compelling, and allowed the industry to grow so quickly? ‣ Not video, audio, or text by itself, since these all predated video games by many years Interactivity! ‣ Computing power makes this interactivity possible. “Just as the schwerpunkt of computers is processing, so too the schwerpunkt of all software is interactivity—and this goes double for games.” “Graphics, animation, sound, and music are all necessary to gaming, and they’re all important, but they’re not the schwerpunkt. Interactivity (sometimes called “gameplay”) is the real schwerpunkt of games.” ‣ Chris Crawford on Game Design, p. 74. ‣ Schwerpunkt: focal point, or, concentration of effort point, or, central point of attack

Definition of Interactivity Crawford uses a conversational metaphor Interactivity is, “a cyclic process in which two active agents alternately (and metaphorically) listen, think, and speak.” (p. 76) In computer games, the computer takes the role of one agent, and hence interactivity for video games becomes: ‣ “How can we program the computer to be an entertaining conversational (metaphorically speaking) partner?” (p. 77) ‣ Computer must ❖ Listen well ❖ Give the player the opportunity to say anything relevant to the situation ❖ Must think well ❖ Must speak well

Interactivity Feedback Loop Can view a computer game as a kind of control system ‣ Game creates output ‣ Player reacts to this output by making decisions and taking action ❖ This generates one or more inputs ‣ Game reacts to these inputs, creating more outputs game creates output player makes internal decision player takes action Rules of Play, p. 316

High Interactivity What is high and low interactivity in a game? ‣ Is a fast-paced action game more interactive than a complex, slow- moving strategy game? ‣ Not necessarily. If two people talk quickly, does that make their conversation more interactive? High interactivity comes when both sides are engaged in high-quality listening, high-quality thinking, high-quality speaking.

Assessing Interactivity in a Game Crawford states that you can estimate the interactivity level of any game by asking three questions: ‣ How much of what the player might desire to say does the game permit the player to actually say? ‣ How well does the game think about the player’s inputs? ‣ How well does the game express its reactions?

Applying the Questions Fast-paced action game: ‣ Game allows player to say a limited number of words (move up, down, left, right, fire, etc.) ‣ Player can say these words quickly ‣ Processing is simplistic: just move around on a map ‣ Expressiveness is complete, within the very limited confines of the world. ‣ Conclusion: small amount of interaction

Applying the Questions (2) Civilization ‣ Pace is slower, but player has wide range of things they can express ‣ Game executes complex set of algorithms. ‣ Listening and thinking are much deeper in this game ‣ Expressiveness is also quite high – many possible pieces to move, possible interactions among pieces ‣ Conclusion: Civilization is clearly a very interactive game OK, so are real time strategy games like Age of Empires or Empire Earth more interactive than Civilization?

Graphic Realism Crawford lists as a common mistake, “obsession with cosmetics” (p. 107) Five common motivations for putting good graphics and sound in a game: ‣ To further the gameplay ‣ To permit the player to show off the superior cosmetic capabilities of his new computer ‣ To show off the superior technical prowess of the programmer ‣ To keep up with the competition ‣ To provide the player with images and sounds that are intrinsically pleasing Crawford: The first reason is the only good reason for pursuing cosmetics. ‣ Agree or disagree?

Process Intensity vs Data Intensity Process intensity is the degree to which a program emphasizes processes instead of data. ‣ Process is algorithms, equations, branches ‣ Data is reflected in data tables, images, sounds, text Analogies ‣ Language: nouns vs verbs ‣ Economics: goods vs services ‣ Computers: bits and cycles

Crunch per Bit Ratio “Because process intensity is so close to the essence of ‘computeriness,’ it provides us with a useful criterion for evaluating the value of any piece of software. That criterion is a vague quantification of the desirability of process intensity. It uses the ratio of operations per datum, which I call the crunch per bit ratio.” (Chris Crawford on Game Design, p. 89)

Core Game Mechanic To have interactivity, must have interaction from player ‣ The player performs some action or actions.... ‣... that intervene in the game world. ‣ Usually, one or more of these actions occurs very frequently, and is the dominant activity of the player ‣ This is the game’s core mechanic Core Game Mechanic ‣ The essential play activity players perform over an over again ❖ Rules of Play, p ‣ When designing a game, an important question to resolve is: What does the player do? ‣ Your design is in trouble until you can crisply answer this question ❖...and the answer sounds like fun

Examples of Core Game Mechanic Breakout ‣ Player turns knob on controller (or move lever of joystick) to move paddle left and right ‣ Choose where ball hits on paddle to control movement of ball

Examples of Core Game Mechanic (2) Most platformer games ‣ Player moves left and right, and jumps ‣ Avoid moving enemies Core game mechanic isn’t all of the kinds of interactions a player may have with a game ‣ More focused: only the most frequent and important interactions ‣ In Kirby’s Adventure (NES), in addition to the typical moving and jumping, the core mechanic includes inhaling

Examples of Core Game Mechanics For most shmups, core game mechanic is: ‣ Move to avoid enemies and position ship ‣ Firing at enemies ‣ Collecting powerups ‣ Different games can alter this. ❖ In Radiant Silvergun, part of the core mechanic is selecting which weapon to use Perfect Cherry Blossom

Core Mechanic Discussion What is the core game mechanic in the following games? ‣ Guitar Hero II ‣ Mass Effect ‣ Halo 2/3 ‣ Ratchet & Clank: Future