/** Check for collision */
private void checkRebounce() {
// check for left/right/top wall
if (ball.getX() < 0) {
vx *= -1;
ball.move(vx, 0);
return;
} else if ((ball.getX() + 2 * BALL_RADIUS) > getWidth()) {
vx *= -1;
ball.move(vx, 0);
return;
} else if (ball.getY() < 0) {
ball.setLocation(ball.getX(), -ball.getY());
vy *= -1;
return;
}
// check for collision with bricks: from the four vertexs
lefttop = getElementAt(ball.getX(), ball.getY());
righttop = getElementAt(ball.getX() + 2 * BALL_RADIUS, ball.getY());
leftbottom = getElementAt(ball.getX(), ball.getY() + 2 * BALL_RADIUS);
rightbottom = getElementAt(ball.getX() + 2 * BALL_RADIUS, ball.getY() + 2 * BALL_RADIUS);
if ((lefttop != null) && (righttop != null) && (lefttop != board) && (lefttop != mylabel)) {
remove(lefttop);
num_brick_left--;
vy *= -1;
} else if ((righttop != null)
&& (rightbottom != null)
&& (righttop != board)
&& (righttop != mylabel)) {
remove(righttop);
num_brick_left--;
vx *= -1;
} else if ((rightbottom != null)
&& (leftbottom != null)
&& (rightbottom != board)
&& (rightbottom != mylabel)) {
remove(rightbottom);
num_brick_left--;
vy *= -1;
} else if ((leftbottom != null)
&& (lefttop != null)
&& (leftbottom != board)
&& (leftbottom != mylabel)) {
remove(leftbottom);
num_brick_left--;
vx *= -1;
}
// check for collision with board
if (getElementAt(ball.getX(), (ball.getY() + BALL_RADIUS / 2)) == board) {
vy *= -1;
ball.move(0, vy);
}
}
private void PrecisionPaddle() {
if (ball.getY()
> HEIGHT
- PADDLE_Y_OFFSET
- PADDLE_HEIGHT
- BALL_RADIUS * 2) { // check if the ball drops below the paddle
double diff = ball.getY() - (HEIGHT - PADDLE_Y_OFFSET - PADDLE_HEIGHT - BALL_RADIUS * 2);
ball.move(0, -2 * diff); // move ball an amount equal to the amount it drops below the paddle
}
}
private void checkForCollision() {
// check if ball has hit floor. If so, bounce it upwards.
if (ball.getY() > getHeight() - DIAM_BALL) {
bounceClip.play();
yVel = -yVel * BOUNCE_REDUCE; // bounces back almost to BOUNCE_REDUCE * starting height
// moves ball back above the floor the same distance it would have dropped below the floor in
// same time
double diff = ball.getY() - (getHeight() - DIAM_BALL);
ball.move(0, -2 * diff);
}
}
// Update/move ball down and sideways. yVel increases each cycle, due to gravity.
private void moveBall() {
yVel += GRAVITY;
ball.move(xVel, yVel);
}
private void startFall() {
ball.move(vx, vy);
pause(DELAY);
ball.sendToBack();
}
/** Move the ball */
private void moveBall() {
ball.move(vx, vy);
}