137 lines
4.2 KiB
Plaintext
137 lines
4.2 KiB
Plaintext
// This file is part of www.nand2tetris.org
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// and the book "The Elements of Computing Systems"
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// by Nisan and Schocken, MIT Press.
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// File name: projects/11/Pong/PongGame.jack
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/**
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* Represents a Pong game.
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*/
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class PongGame {
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static PongGame instance; // the singelton, a Pong game instance
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field Bat bat; // the bat
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field Ball ball; // the ball
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field int wall; // the current wall that the ball is bouncing off of.
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field boolean exit; // true when the game is over
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field int score; // the current score.
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field int lastWall; // the last wall that the ball bounced off of.
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// The current width of the bat
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field int batWidth;
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/** Constructs a new Pong game. */
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constructor PongGame new() {
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do Screen.clearScreen();
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let batWidth = 50; // initial bat size
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let bat = Bat.new(230, 229, batWidth, 7);
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let ball = Ball.new(253, 222, 0, 511, 0, 229);
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do ball.setDestination(400,0);
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do Screen.drawRectangle(0, 238, 511, 240);
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do Output.moveCursor(22,0);
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do Output.printString("Score: 0");
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let exit = false;
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let score = 0;
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let wall = 0;
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let lastWall = 0;
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return this;
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}
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/** Deallocates the object's memory. */
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method void dispose() {
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do bat.dispose();
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do ball.dispose();
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do Memory.deAlloc(this);
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return;
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}
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/** Creates an instance of Pong game, and stores it. */
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function void newInstance() {
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let instance = PongGame.new();
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return;
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}
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/** Returns the single instance of this Pong game. */
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function PongGame getInstance() {
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return instance;
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}
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/** Starts the game, and andles inputs from the user that control
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* the bat's movement direction. */
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method void run() {
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var char key;
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while (~exit) {
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// waits for a key to be pressed.
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while ((key = 0) & (~exit)) {
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let key = Keyboard.keyPressed();
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do bat.move();
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do moveBall();
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do Sys.wait(50);
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}
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if (key = 130) { do bat.setDirection(1); }
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else {
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if (key = 132) { do bat.setDirection(2); }
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else {
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if (key = 140) { let exit = true; }
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}
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}
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// Waits for the key to be released.
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while ((~(key = 0)) & (~exit)) {
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let key = Keyboard.keyPressed();
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do bat.move();
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do moveBall();
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do Sys.wait(50);
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}
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}
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if (exit) {
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do Output.moveCursor(10,27);
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do Output.printString("Game Over");
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}
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return;
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}
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/**
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* Handles ball movement, including bouncing.
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* If the ball bounces off a wall, finds its new direction.
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* If the ball bounces off the bat, increases the score by one
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* and shrinks the bat's size, to make the game more challenging.
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*/
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method void moveBall() {
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var int bouncingDirection, batLeft, batRight, ballLeft, ballRight;
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let wall = ball.move();
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if ((wall > 0) & (~(wall = lastWall))) {
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let lastWall = wall;
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let bouncingDirection = 0;
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let batLeft = bat.getLeft();
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let batRight = bat.getRight();
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let ballLeft = ball.getLeft();
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let ballRight = ball.getRight();
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if (wall = 4) {
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let exit = (batLeft > ballRight) | (batRight < ballLeft);
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if (~exit) {
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if (ballRight < (batLeft + 10)) { let bouncingDirection = -1; }
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else {
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if (ballLeft > (batRight - 10)) { let bouncingDirection = 1; }
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}
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let batWidth = batWidth - 2;
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do bat.setWidth(batWidth);
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let score = score + 1;
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do Output.moveCursor(22,7);
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do Output.printInt(score);
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}
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}
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do ball.bounce(bouncingDirection);
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}
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return;
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}
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} |