Java and Game Programming

• Java Standard Edition (J2SE) Standard Development Kit (SDK) (or JDK).
• JDK version >= 6.
• Eclipse or other IDE such as IntellJ or NetBeans (or sometimes just a plain text editor and the command line).

• Java manages its namespace using packages.
• A package is a group of related classes.
• Some common packages that we may use:
  • java.lang.* (DEFAULT)
  • java.awt.*
  • javax.swing.*
  • java.io.*
  • java.net.*
• import makes a package name available in a shorter form.
  • Example: “import java.awt.*;” makes everything in class java.awt accessible as its short name.
    • Afterward, for example, you can use the short name “Graphics” instead of “java.awt.Graphics”.

• Don't want to write an overly long main() method
• Methods are functions: they do a certain well-defined task and should be as small as possible

• public - Can be accessed anywhere, including other classes, packages
• private - Can only be accessed from methods within the same class
• protected - Can be accessed in all methods of classes in the same package.

• Static methods are methods that belong to a class itself, rather than class instances (objects).

• You can define your own constants by using “static final”.
  • Example: public static final int MAX_LEVELS = 10;
  • But using a public Enum would be preferred if you have a group of related constants that you want to use in a game.

• A part of almost every game
• Can use the Random class or Math.random()
• import java.util.Random;
• Creating and using a random number generator:

               Random generator = new Random();
               
               // To get a random integer where the range of your random number
               // is between 0 to N-1:
               int throw = generator.nextInt(N);
               
               // To start at 1:
               int throw = generator.nextInt(N - 1) + 1;
               
               // Setting the random seed (an integer used to set the starting point
               // for generating a series of random numbers):
               Random generator = new Random (SEED);
               // or use generator.setSeed(SEED);
               
               // In order to generate truly random numbers, the seed should be an
               // unpredictable value (e.g., entropy created by random key presses
               // or mouse movements).

• Java in “real games”
  • Tom Clancy's Politika, Star Wars Galaxies (the game logic), Puzzle Pirates, Galactic Village, Runescape, freeware/shareware games, MINECRAFT
• java-gaming.org
• Java game engines or game development libraries exist (partial list at http://en.wikipedia.org/wiki/List_of_game_engines)
  • Most significant may be LWJGL due to Minecraft
  • We will introduce the Java-based, multi-platform game development framework, LibGDX, in this class as an alternative to using pure Java.
    • Uses LWJGL and other libraries
    • Recent Gamasutra blog entry on LibGDX and game development: http://www.gamasutra.com/blogs/YanickBourbeau/20150902/252624/Linux_game_development_in_2015.php

• http://rockhopper.monmouth.edu/~jchung/download/jspout.jar
  • Download and run with $ java -jar jspout.jar.

• 2013 winner of Java4K competition
• http://www.x2d.org/java/4k/flywrench4k/
  • Windows: Run “Configure Java” to add security exception for http://www.x2d.org.
    • Can't run in school Windows labs at all.
      • Java applets are dead.