CSCE 590E Spring 2007
Game Design
By Jijun Tang
Announcements
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We will NOT have lab on Wednesday
Some groups have not sent me the
names
First small game is due before spring
break
Our first presentation of game design
is scheduled before spring break
Group Ideas
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Let’s share some ideas
Definitions
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Some time lack standard (concrete)
definitions
Game: Object of rule-bound play
Play: Interactions to elicit emotions
Aesthetics: Emotional responses during play
Frame: The border of a game’s context
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Inside the frame is in the game
Outside the frame is real life
The Language of Games
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Why do we play?
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What is the nature of games?
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Not a designer’s problem
Not a designer’s problem
How is a game formed of parts?
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A designer’s problem
Approaching Design
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Computer games are an art form
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Game design practices can be taught
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Digit arts
You do not need to be genius to design games
Technical discipline like music, film, poetry
Approaching Design
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A model represents something
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Mental/Cognitive
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Concepts
Beliefs
Maps
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Examples:
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Locations
Relationships
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Mathematical
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Equations
Formulas
Algorithms
Approaching Design
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Abstract model
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Conceptual and idealized
A tool for investigating specific questions
Simplifies thinking to help understand problems
May include assumptions thought to be false
Abstract game
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One rule
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The piece is moved to the open square
A Player-Game Model
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A model of the player – game relationship
PLAYER
Mechanics
GAME
Interface
System
A Player-Game Model
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Mechanics
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Interface
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Things the player does
Communication between player and
game
System
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Underlying structure and behavior
Control and State Variables
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Control variables
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Inputs from players
State variables
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Quantities indicating game state
Play Mechanics
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Gameplay
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Feelings of playing a particular game
Activities engaged in a particular game
(Play/game) Mechanics
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Specific to game activities
“What the player does”
Actions
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Actions not often in discrete stages
Not all actions progress through all
stages
Seven Stages of Action
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
T HE GAME
Goals
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Execution
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Intention to act
Sequence of action
Execution of action
sequence
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Evaluation
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Evaluating
interpretations
Interpreting perceptions
Perceiving states
Seven Stages of Action
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A goal is formed
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Models the desired state
The desired result of an action
Examples:
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Have a glass of water in hand
Capture a queen
Taste ice cream
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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Goals turned into intentions to act
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Specific statements of what is to be done
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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Intentions put into an action sequence
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The order internal commands will be performed
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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The action sequence is executed
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The player manipulates control variables
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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The state of the game is perceived
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State variables are revealed via the interface
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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Player interprets their perceptions
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Interpretations based upon a model of the system
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Seven Stages of Action
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Player evaluates the interpretations
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Current states are compared with intentions and goals
Intention
to act
Sequence of
action
Execution of
action sequence
Evaluating
interpretations
Interpreting
perceptions
Perceiving
states
Goals
T HE GAME
Designer and Player Models
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Systems are built from designer mental models
Design models may only anticipate player goals
User's
Model
Design
Model
Designer
System
System Image
User
Designer and Player Models
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Players build mental models from mechanics
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Based upon interactions with the system image
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The reality of the system in operation
Not from direct communication with designers
Player and designer models can differ significantly
User's
Model
Design
Model
Designer
System
System Image
User
Core Mechanics
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Typical patterns of action
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Fundamental mechanics cycled repeatedly
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Examples:
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Action shooters – run, shoot, and explore
Strategy game – explore, expand, exploit, exterminate
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referred to as the “four X’s”
Premise
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The metaphors of action and setting
Directs the player experience
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Provides a context in which mechanics fit
Players map game states to the premise
Premise
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Story is the typical example of premise
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Time
Place
Characters
Relationships
Motivations
Etc.
Premise
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Premise may also be abstract
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Tetris operates under a metaphor
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The metaphor: arranging colored shapes
Encompasses all game elements
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Player discussions use the language of
the premise
Premise
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Games are models
Activities being modeled form premise
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Actions may appear similar in model
Usually are fundamentally quite different
Sports games are good examples:
Playing video games isn’t like playing the
sport
Premise
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Goes beyond setting and tone
Alters the players mental model
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Basis of player understanding and strategy
Possible: Capable of happening in the real
world
Plausible: Possible within the unique world of
premise
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“Makes sense” within the game’s premise
Consistent with the premise as understood
Choice and Outcome
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Choice
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Outcome
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A question asked of the player
The end result of a given choice
Possibility space
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Represents the set of possible events
A “landscape” of choice and outcome
Choice and Outcome
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Consequence or Weight
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The significance of an outcome
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Greater consequences alter the course of the
game more significantly
Choices are balanced first by
consequence
Choice and Outcome
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Well-designed choice
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Often desirable and undesirable effects
Should relate to player goals
Balanced against neighboring choices
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Too much weight to every choice is
melodrama
Orthogonal choices – distinct from others
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Not just “shades of grey”
Qualities of Choice
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Terms in which to discuss choices
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Hollow – lacking consequence
Obvious – leaves no choice to be made
Uninformed – arbitrary decision
Dramatic – strongly connects to feelings
Weighted – good and bad in every choice
Immediate – effects are immediate
Long-term – effects over extended period
Orthogonal – choices distinct from each other
Goals and Objectives
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Objectives
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Designed tasks players must perform
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Rigid requirements – formal
Goals
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An intentional outcome
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Notions that direct player action
Scales all levels of motivation
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From selecting particular strategies…
…to basic motor actions (e.g. pressing a button)
Goals and Objectives
Find sword
Rescue dragon
Kill princess
Find sword
Kill dragon
Rescue princess
Designer
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System
User
Objectives and goals can differ
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Players goals reflect their understanding of the game
Designers must consider how the game communicates with
players
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Affordances – the apparent ways something can be used
Resources/Economies
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Resources
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Things used by agents to reach goals
To be meaningful, they must be…
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Useful – provide some value
Limited – in total or rate of supply
Economies
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Systems of supply, distribution, consumption
Questions regarding game economies:
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What resources exist?
How and when will resources be used?
How and when will resources be supplied?
What are their limits?
Player Strategy
Situation
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Result
People usually reason with commonsense
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Action
A view of linear causation – cause and effect
Complex systems do not behave linearly
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Players need information to support linear
strategy
Game Theory
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Game Theory
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Utility
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A measure of desire associated with an outcome
Payoffs
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Branch of economics
Studies decision making
The utility value for a given outcome
Preference
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The bias of players towards utility
Game Theory
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Rational Players
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Abstract model players – not real people
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Always try to maximize their potential utility
Solve problems using pure logic
Always fully aware of the state of the game
Game Theory
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Games of skill
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Games of Chance
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One-player games
Outcomes determined solely by choices
One-player games
Outcomes determined in whole or part by nature (chance)
Games of Strategy
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Competitions between two or more players
Game Theory
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Decision under certainty
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Risky decisions
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Players know the outcome of any
decision
Probabilities of nature are known
Decision under uncertainty
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Probabilities of nature are unknown
Interface
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Interface
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Input
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Input, presentation, and feedback.
Player to game
Output
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Game to player
Interface
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Contains both hardware, software, and
performance elements.
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Hardware such as game pads
Software such as engines
Performance such as pressing a button
Graphical user interface (GUI)
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A visual paradigm of control
GUI is the first impression of the game
And hard to be cross-platform
First: 1984 Macintosh GUI with mouse
Interface
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Typical perspectives:
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First-person
Over-the-shoulder (OTS)
Overhead (top-down)
Side
Isometric
First person
OTS
Overhead and Side
Isometric
Audio Interface
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General categories of audio
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Music
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Powerful tool for establishing mood and
theme
Pay attention to license issues
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The campus is cited 960 times last year
Sound effects
Dialog
Input Interface
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Controls
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Physical input devices: mouse, key,
motion, etc
Control inputs
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User manipulations of the controls
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They are not strategies
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Example: a sequence of buttons to perform a
combo
Strategies involve deciding when to perform
Keys
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Key map or control table
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A diagram showing control input, action,
and context
Mapping: An understood relationship
between two things
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Map keys by looking at your own hand
Suit your targeted players: small/big
Key maps
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Complex games have many keys and
combinations
Ship your game with a detailed key map
Control diagrams
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Show input, action, and context
Example
Front End Interface
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Front-end
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In application software
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The visible portion of the application
In games
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GUI elements not displayed during play
Used mainly for input/configure/choice
Hud Interface
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HUD (Head-Up Display)
Displays during play
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Shows and other information difficult to present
directly in the game environment
Examples
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Scores
Resource levels
Mini Map
Chat
Alerts
Level
Huds