The Breakout Game (Complete Version) - Learning Java Through Games - page 248

private Ball(Color color , Ellipse2D.Double ellipse ) {
super (ellipse ,color , true );

}

public Ball getVirtualBall () {
return new Ball( super .getColor() , new Ellipse2D.Double(getX()+dx,
getY()+dy , SIZE , SIZE) ) ;

}

public void move ( ) {
if (getX() + dx < 0)

{

dx = 1;
if (getX() + getWidth() + dx

> panel .getWidth() ) {

1;
if (getY() + dy < 0)

dx = −

{

dy = 1;
if (getY()+getHeight () +dy > panel . getHeight ()) {
dy = − 1;
super .move(dx, dy);
} public void goUp ( ) {
dy = − 1;

}

public void goDown ( ) {
dy = 1;

}

public void goLeft () {
dx = − 1;

}

{

public void goRight ()

dx = 1;

}

}

The getVirtualBall method creates a new ball that corresponds to the next position
of the ball. It uses a new private constructor that creates a new ball object from the given
color and elliptical shape. We have also included the goDown() , goUp() , goLeft() ,and
goRight() methods. They can be used to change the trajectory of the ball.
We also need to modify the BreakoutShape class and add the following method.
class BreakoutShape {
...
public boolean intersects (BreakoutShape other ) {
return shape . intersects ( other . shape . getBounds () ) ;
} ...

}