From a000308104aab27c2dde9a306f1bc654b2db4806 Mon Sep 17 00:00:00 2001
From: Yuchen Pei <me@ypei.me>
Date: Wed, 29 Nov 2017 12:30:41 +0100
Subject: first commit

---
 projects/11/Square/SquareGame.jack | 81 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 projects/11/Square/SquareGame.jack

(limited to 'projects/11/Square/SquareGame.jack')

diff --git a/projects/11/Square/SquareGame.jack b/projects/11/Square/SquareGame.jack
new file mode 100644
index 0000000..4fe7e39
--- /dev/null
+++ b/projects/11/Square/SquareGame.jack
@@ -0,0 +1,81 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/11/Square/SquareGame.jack
+
+// (same as projects/09/Square/SquareGame.jack)
+
+/**
+ * Implements the Square Dance game.
+ * This simple game allows the user to move a black square around
+ * the screen, and change the square's size during the movement.
+ * When the game starts, a square of 30 by 30 pixels is shown at the
+ * top-left corner of the screen. The user controls the square as follows.
+ * The 4 arrow keys are used to move the square up, down, left, and right.
+ * The 'z' and 'x' keys are used, respectively, to decrement and increment
+ * the square's size. The 'q' key is used to quit the game.
+ */
+
+class SquareGame {
+   field Square square; // the square of this game
+   field int direction; // the square's current direction: 
+                        // 0=none, 1=up, 2=down, 3=left, 4=right
+
+   /** Constructs a new Square Game. */
+   constructor SquareGame new() {
+      // Creates a 30 by 30 pixels square and positions it at the top-left
+      // of the screen.
+      let square = Square.new(0, 0, 30);
+      let direction = 0;  // initial state is no movement
+      return this;
+   }
+
+   /** Disposes this game. */
+   method void dispose() {
+      do square.dispose();
+      do Memory.deAlloc(this);
+      return;
+   }
+
+   /** Moves the square in the current direction. */
+   method void moveSquare() {
+      if (direction = 1) { do square.moveUp(); }
+      if (direction = 2) { do square.moveDown(); }
+      if (direction = 3) { do square.moveLeft(); }
+      if (direction = 4) { do square.moveRight(); }
+      do Sys.wait(5);  // delays the next movement
+      return;
+   }
+
+   /** Runs the game: handles the user's inputs and moves the square accordingly */
+   method void run() {
+      var char key;  // the key currently pressed by the user
+      var boolean exit;
+      let exit = false;
+      
+      while (~exit) {
+         // waits for a key to be pressed
+         while (key = 0) {
+            let key = Keyboard.keyPressed();
+            do moveSquare();
+         }
+         if (key = 81)  { let exit = true; }     // q key
+         if (key = 90)  { do square.decSize(); } // z key
+         if (key = 88)  { do square.incSize(); } // x key
+         if (key = 131) { let direction = 1; }   // up arrow
+         if (key = 133) { let direction = 2; }   // down arrow
+         if (key = 130) { let direction = 3; }   // left arrow
+         if (key = 132) { let direction = 4; }   // right arrow
+
+         // waits for the key to be released
+         while (~(key = 0)) {
+            let key = Keyboard.keyPressed();
+            do moveSquare();
+         }
+     } // while
+     return;
+   }
+}
+
+
+
-- 
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