104 lines
2.8 KiB
Plaintext
104 lines
2.8 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/09/Square/SquareGame.jack
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/**
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* Implements the Square Dance game.
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* In this game you can move a black square around the screen and
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* change its size during the movement.
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* In the beginning, the square is located at the top-left corner
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* of the screen. The arrow keys are used to move the square.
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* The 'z' & 'x' keys are used to decrement and increment the size.
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* The 'q' key is used to quit the game.
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*/
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class SquareGame {
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// The square
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field Square square;
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// The square's movement direction
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field int direction; // 0=none,1=up,2=down,3=left,4=right
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/** Constructs a new Square Game. */
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constructor SquareGame new() {
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let square = Square.new(0, 0, 30);
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let direction = 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 square.dispose();
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do Memory.deAlloc(this);
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return;
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}
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/** Starts the game. Handles inputs from the user that control
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* the square's movement, direction and size. */
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method void run() {
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var char key;
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var boolean exit;
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let exit = false;
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while (~exit) {
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// waits for a key to be pressed.
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while (key = 0) {
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let key = Keyboard.keyPressed();
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do moveSquare();
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}
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if (key = 81) {
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let exit = true;
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}
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if (key = 90) {
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do square.decSize();
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}
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if (key = 88) {
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do square.incSize();
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}
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if (key = 131) {
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let direction = 1;
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}
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if (key = 133) {
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let direction = 2;
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}
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if (key = 130) {
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let direction = 3;
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}
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if (key = 132) {
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let direction = 4;
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}
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// waits for the key to be released.
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while (~(key = 0)) {
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let key = Keyboard.keyPressed();
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do moveSquare();
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}
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}
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return;
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}
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/** Moves the square by 2 pixels in the current direction. */
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method void moveSquare() {
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if (direction = 1) {
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do square.moveUp();
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}
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if (direction = 2) {
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do square.moveDown();
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}
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if (direction = 3) {
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do square.moveLeft();
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}
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if (direction = 4) {
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do square.moveRight();
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}
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do Sys.wait(5); // Delays the next movement.
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return;
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}
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}
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