Module 2: Developing a game

2.9 Exercise: Open the file PrimeGame.java in your editor and carefully examine the code.

Let's walk through the design:

• First, let's take a look at the key global variables:

      static int N = 10;                         // Grid size N×N
      static int[][] board = new int [N][N];     // board[i][j] == a number
      static int[][] points = new int [N][N];    // the points won/lost at a cell
      static int primePointMultiplier = 10;      // 10*prime# for positive points
  
      // Current locations of the two players:
      static int playerAX=0, playerAY=N-1;
      static int playerBX=N-1, playerBY=N-1;
  
      // Current scores:
      static int playerApoints=0, playerBpoints=0;
       

• Thus the main idea of the whole program is:

       Do the initialization: 
           Make the board, draw the board, initalize locations
  
       while (! over) {
           move player A
           move player B
       }
  
       print points and game result
       

• This is essentially what's in the method executeGame() (the initialization is done in methods called from main()):

      static void executeGame ()
      {
  	boolean over = false;
  	boolean canMoveA = true, canMoveB = true;
  	int numSteps = 0;
  
  	while (! over) {
  
  	    numSteps++;
  
  	    canMoveA = checkCanMoveA ();     // Need to see if A can move.
  
  	    if (canMoveA) {                  // A can move.
  		boolean isLegal = moveA ();  // A's move worked.
  		if (! isLegal) {
  		    playerApoints = -1;      // If not, A loses.
  		    break;                   // End the game right away.
  		}
  	    }
   
              // ... similar code for player B ...
  
           }
       

• Player A is "stuck" if it's on the lowest row and rightmost cell:

      static boolean checkCanMoveA ()
      {
  	// You can't move A if it's on the lowest level and x >= N.
  	return ( ! ((playerAY == 0) && (playerAX >= N-1)) );
      }
       

• What remains is to actually arrange for either a manual move or to call the appropriate program for a move. Here's some of the code in moveA():

      static boolean moveA ()
      {
  	char c = ' ';                     // Default (to catch errors).
  	int[][] b = copyArray (board);    // Make a copy to prevent tampering.
  	if (gameType == 1) {              // PlayerA vs Player B.
      	    sleep (sleepTime);
  	    c = PlayerA.move (b, playerAX, playerAY, playerBX, playerBY);
  	}
  	else if (gameType == 2) {
  	    // ... etc .. for all the game types ...
  	}
  
          // Evaluate legality of move and then actually change
          // playerAX, playerAY, and adjust points.
          // ...
      }
       

• The code for player B is nearly identical.

• There are also some supporting methods like copying the board. Why copy the board? We send a copy to each player in case a player's strategy code inadvertently writes over the board.

• Finally, let's take a look at the initialization code:

      static void makeBoard ()
      {
  	// First make an array of numbers 1 .. M=N*N
  	int[] numbers = GameArrayTool.shiftedArray (N);
  
  	// Next, place numbers on the board.
  	GameArrayTool.putNumbersOnBoard (board, numbers);
  
  	System.out.println ("Initial board:");
  	GameArrayTool.printBoard (board);
  
  	// Now do points. 
  	for (int y=0; y<N; y++) {
  	    for (int x=0; x<N; x++) {
  		if (GameArrayTool.isPrime(board[x][y])) {
  		    points[x][y] = board[x][y] * primePointMultiplier;
  		}
  		else {
  		    points[x][y] = -board[x][y];
  		}
  	    }
  	}
      }
       

  But you already know this code.

Ready to build your own game?

• There are simple games and puzzles without much by way of graphics or storytelling.
         ⇒ These are easy for a single person to develop.

• A full-fledged video game, on the other hand, needs a large team:
  • Graphic artists to design and create imagery.
  • Game engine software developers to create the logic of the game.
  • Software developers to handle communication, servers and such for multi-player online games.
  • Software developers for interfacing with game hardware.

• Employment in the game industry is a popular choice for students but it's highly competitive.

• To secure a future in the game industry, it's probably helpful to do a few things:
  • Take courses in fine arts so you learn how to use tools for digital arts and animation.
  • Get a Master's degree in game development and computer graphics, which will certainly cover the above and typically position you for both the game and animation industries.
  • Build some games because that's how you open doors for interviews.
  • Seek an internship in a game development company.
  (And let's not forget ... complete the GatewayToCS program.)

Meta

2.10 Audio:


On to Module 3