Game Design and Programming

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Game Design and Programming
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Objectives

• Classify the games
• How games are design
• How games are implemented
• What are the main components of a game engine

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Designing Games

• 3D mathematics for games may be hard but
  designing games is even harder
• Having a fun game is a challenging issue
• If the game is not well-design, the fancy 3D
  graphics will not do any help
• Coming up with a game idea is usually not
  difficult
• The level of Details, final implementation, and
  the look make the difference between professional
  and novice games

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Types of games

• The first step for designing a game is to the
  genre of your game
• Action and Adventure
• Fighting games
• Sport games
• Strategy/war games
• Pure puzzle and board games
• Mechanical simulations
• Flying, boating, racing, etc.
• Ecosystem simulations
• Artificial system of some kind such as ant
  colony, city, etc.

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Action Adventure
Puzzles
Strategy/War
Sports
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Simulation Racing
Ecosystem simulation
Fighting
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Brainstorming

• Once the type of the game is specified, you must
  come up with a fun game
• Brainstorm and through ideas. Existing games,
  reading science fiction books, and watching 3D
  movies can trigger your creativity.
• Keep it simple dont bite off more than what you
  can chew!

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Design document and Storyboard

• Once the ideas are set in your mind, you need to
  get them on paper
• A design document outlines the details of the
  game
• Who are the main characters?
• What is the main idea of the game?
• How to win the game?
• What are the levels of the game?
• What are the cool features in the game?
• Making a storyboard is often the best to start
  and understand the game

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Is it Fun?

• Reality check
• Will the game be fun?
• Will people enjoy it?
• Are the cool features cool enough to attract
  people?
• Be objective and see the game from others eyes
• Remember that the cool features and the attention
  to details make the game fun

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The big picture!
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The components of a game

• A game is a real-time application that includes
• Interactivity mouse, keyboard, joystick
• Visual the frames drawn into the display
• Audio any sound or music playing during playing
• A video game is
• A continuous loop that
• performs logic and
• draws an image on the screen, usually at a rate
  of 30 frames per second (fps) or more.
• This is similar to how a movie is displayed,
  except that you are creating the movie as you
  play.

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Components of a game (2)
The main game loop! while (!gameover)
get input process input simulate
physics and AI redraw Simple!
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The components of a game (3)

• Initialization
• perform the usual operations
• Memory allocation
• Graphics device creation and initialization
• Resource acquisition
• Loading data from disk.
• Game Loop
• This is the main loop of the game.
• It is where the actions of the game begin and
  continue until the user exists the main game
  loop.

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The components of a game (4)

• Interactivity
• retrieves player inputs
• Process the inputs or buffer them for later use
  in Artificial Intelligence (AI) and game logic
• AI and Game Logic
• The majority of the game code is in here
• The artificial intelligence, the physics, and the
  logic of the game are executed
• the results are used to draw the next frame on
  the screen

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The components of a game (4)

• Rendering
• the results of the players input and the
  execution of game AI and logic are used to
  generate the next frame of animation for the
  game.
• This frame is usually drawn on an off-screen
  (back) buffer area
• A swapping of the front and the back buffer is
  performed to display the frame.

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The components of a game (5)

• Display synchronization
• To avoid a variable frame rate, you must set the
  frame rate to a fixed value
• Use timing/waiting functions to hold the frame
  rate to a fixed value
• Cleaning up
• When the user exits the game, we have to make
  sure to release the resources and clean up the
  system
• Delete any pointers
• Close any files, databases, or connections
• Return to the window mode if full-screen mode is
  used

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How to control the main loop?

• The game main loop is usually a finite state
  machine (FSM) that contains a number of states
  and the transitions between these states

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Show us the code!

• // implementation of main game loop
• while (gameState!GAME_EXIT)
• // what state is game loop in
• switch (gameState)
• case GAME_INIT // the game is initializing
• // allocate all memory and load the
  resources
• initialize()
• // move to menu
  state
• gameState
  GAME_MENU
• break
• case GAME_MENU // the
  game is in the menu mode
• // call the main
  menu function and let it switch states
• gameState
  getMenuChoice()
• // You can force a
  RUN state here if you want.
• break
• case GAME_STARTING //
  the game is about to run
• // this state is
  optional, but usually used to set things up right
  
• // before the game
  is run you might do a little more house keeping
  here
• setupForRun()

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Show us the code! (2)

• case GAME_RUN // the game is now running
• // this section contains the entire
  game logic loop
• // clear the display
• clearDisplay()
• // get the inputs and interact with
  the user
• getInput()
• // perform logic and AI
• doLogicAI()
• // display the next frame of
  animation
• renderFrame()
• // synchronize the display
• wait()
• // the only way that state can be
  changed is through user interaction in the input
• // section or by maybe losing the
  game.
• break
• case GAME_RESTART // the game is
  restarting
• // this section is a cleanup state
  used to put things in order before running again
• fixUp()
• // switch states back to the menu

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Show us the code! (3)

• case GAME_EXIT // the game is exiting
• // if the game is in this state,
  then cleanup everything
• releaseCleanUp()
• // set the error word to whatever
• error 0
• break
• default
• break
• // end switch
• // end while
• // return error code to operating system
• return(error)

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What is a game engine?

• Provides the core functionality of the game
• Allows for reusable software platform and rapid
  development of games
• Think of the engine of a car!
• A game engine usually includes
• A 2D/3D rendering engine
• A physics/Collision detection engine
• AI
• Sound
• Processing inputs
• Networking
• Example, Crystal space is an open source game
  engine

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Summary
Do you know this? Of course!
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For Later

• Algorithms, data structures, and programming
  tricks for games
• Physics and mathematics for games
• Artificial intelligence
• Determinism
• Randomness