Java Brickbreaker桨碰撞检测

Question

I am trying to make a brickbreaker game and I have run into some issues when it comes to collision detection. If you have ever played brick breaker you know that on the paddle, if the ball is moving to the left and you hit the left side of the top, then it continues moving right. Although, if you hit it on the right side in this case, then the ball changes directions. And also if you hit it on the sides of the paddle, it bounces off on the Y axis. Since I have no idea how to do the top part of the paddle, I can't show you the code because I don't have any :) This is the code that I am using for the sides:

Rectangle rect1 = new Rectangle((int) paddleDir, 570, imsLoader.getImage("paddle1").getWidth(), imsLoader.getImage("paddle1").getHeight());
Rectangle rect2 = new Rectangle((int) ballX, (int) ballY, imsLoader.getImage("ball").getWidth(), imsLoader.getImage("ball").getHeight());
if (rect1.intersects(rect2))
{
    if (rect1.x == rect2.getMaxX() || rect1.getMaxX() == rect2.x)
    {
        ballVX = -ballVX;
        clipsLoader.play("pattleHit", false);
    }
    else
    {
        ballVY = -ballVY;
        ballY += 0.05;
        clipsLoader.play("pattleHit", false);
    }
}

What happens is that the ball when gets hit on the side, just goes right through the paddle going all over the place and when it reaches the other end either goes up or down!

Answer 1

You have to make the ball bounce, right?

Let's look at an example. Think the top square as the ball (I can't draw that nice). When the ball collides from left, it should move right and if it's from right, then go left.

You can achieve this with a simple thing. Don't change the horizontal velocity but instead reverse the vertical one.

if (ball.getBounds().intersects(paddle.getBounds()))
{
    ball.setVy(-ball.getVy());
}

Easy right!

Now let's figure out how to do bounce effect on bricks.

This is a scenario when ball hits the brick. The red area is the intersection. Now notice it carefully.

• If the intersection width is greater than the intersection height, the ball has hit in the bottom or vertical sides of the brick.

• If the intersection height is greater that the intersection width, then it is a horizontal collision.

So we have to first calculate the intersection rectangle. It's so easy with java.

Rectangle intersection = ball.getBounds().intersection(brick.getBounds());

Now let's implement the bouncing.

if (intersection.width >= intersection.height)
{
    ball.setVy(-ball.getVy());
}

if (intersection.height >= intersection.width)
{
    ball.setVx(-ball.getVx());
}

That's it and you should have it fully functional.