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// 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/Pong/Bat.jack
/**
* A graphical Pong bat.
* Displayed as a filled horizontal rectangle that has
* a screen location, a width and a height.
* Has methods for drawing, erasing, moving left and right,
* and changing its width (to make the hitting action more challenging).
* This class should have been called "paddle", following the
* standard Pong terminology. But, unaware of this terminology,
* we called it "bat", and then decided to stick to it.
*/
class Bat {
field int x, y; // the bat's screen location
field int width, height; // the bat's width and height
field int direction; // direction of the bat's movement (1 = left, 2 = right)
/** Constructs a new bat with the given location and width. */
constructor Bat new(int Ax, int Ay, int Awidth, int Aheight) {
let x = Ax;
let y = Ay;
let width = Awidth;
let height = Aheight;
let direction = 2;
do show();
return this;
}
/** Deallocates the object's memory. */
method void dispose() {
do Memory.deAlloc(this);
return;
}
/** Shows the bat. */
method void show() {
do Screen.setColor(true);
do draw();
return;
}
/** Hides the bat. */
method void hide() {
do Screen.setColor(false);
do draw();
return;
}
/** Draws the bat. */
method void draw() {
do Screen.drawRectangle(x, y, x + width, y + height);
return;
}
/** Sets the bat's direction (0=stop, 1=left, 2=right). */
method void setDirection(int Adirection) {
let direction = Adirection;
return;
}
/** Returns the bat's left edge. */
method int getLeft() {
return x;
}
/** Returns the bat's right edge. */
method int getRight() {
return x + width;
}
/** Sets the bat's width. */
method void setWidth(int Awidth) {
do hide();
let width = Awidth;
do show();
return;
}
/** Moves the bat one step in the bat's direction. */
method void move() {
if (direction = 1) {
let x = x - 4;
if (x < 0) { let x = 0; }
do Screen.setColor(false);
do Screen.drawRectangle((x + width) + 1, y, (x + width) + 4, y + height);
do Screen.setColor(true);
do Screen.drawRectangle(x, y, x + 3, y + height);
}
else {
let x = x + 4;
if ((x + width) > 511) { let x = 511 - width; }
do Screen.setColor(false);
do Screen.drawRectangle(x - 4, y, x - 1, y + height);
do Screen.setColor(true);
do Screen.drawRectangle((x + width) - 3, y, x + width, y + height);
}
return;
}
}
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