Breakout game, rectagle collision detection

Question

I am trying to make a copy of the breakout game, but I have problems with checking if two objects (the ball and paddle) intersects.

I have this method for collision detection for now:

public static void handleCollisions() {

    System.out.println(ball.getBounds());        // just to check that they                  
    System.out.println(paddle.getBounds());      //are there and moving correct

    if (ball.getBounds().intersects(paddle.getBounds())) {
        System.out.println("collision");
    }
}

But even though the rectangles for sure intersect at some points, the method never detects anything. I suppose I have done something wrong with some of the classes. Here is the main classes:

package assignment1;

import java.awt.*;
import java.awt.event.*;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;
import javax.swing.*;
import javax.swing.plaf.basic.BasicBorders.RadioButtonBorder;
import java.util.Random; 



public class Breakout extends TimerTask implements KeyListener {            

public static Vector bricks;
public static Ball ball;
public static Paddle paddle;
public static PaintingPanel panel;
public static boolean gameRunning;
public static Breakout game;

public Breakout()
{

}


public static void setupGame()
{
    Paddle paddle = new Paddle(350, 790, 100, 10);  //initial paddle creation                           
    Ball ball = new Ball(393, 790, 7);

    showGUI();
}

public static void beginGame()
{
    gameRunning = true;  

}

public void run()
{
    if(gameRunning == true)
    {


        Ball.move();
        Paddle.move();
        handleCollisions();




        if(Ball.x < 0 || Ball.x > 800 || Ball.y < 0 || Ball.y > 790){
            gameRunning = false;
            System.out.println("Game over");    
        }


    }


}

public static void stopGame()
{   

}



public static void handleCollisions()
{

    System.out.println(ball.getBounds());
    System.out.println(paddle.getBounds());

    if (ball.getBounds().intersects(paddle.getBounds()))
        {
    System.out.println("Yay");
        }

}


public static void main(String[] args)
{   
    Timer t = new Timer();  
    t.schedule(new Breakout(), 0, 40);

    panel = new PaintingPanel(PaintingPanel.contents);
    setupGame();
    beginGame();





    while (gameRunning == true)
    {
            panel.repaint();
    }       

    // TODO a lot
}

private static void showGUI()
{

    JFrame frame = new JFrame("Breakout");  
    game = new Breakout();                   

    frame.addKeyListener(game);

    frame.add(panel);

    frame.setSize(1000,1000);
    frame.setLocationRelativeTo(null);                          //  create game window
    frame.setVisible(true);                                 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   


}


public void keyPressed(KeyEvent e) {
    Paddle.keyPressed(e);   
}


public void keyReleased(KeyEvent e) {
    Paddle.keyReleased(e);
}


public void keyTyped(KeyEvent e) {
    // TODO Auto-generated method stub

}

}

package assignment1;

import java.awt.*;
import java.util.Vector;
import javax.swing.*;

public class PaintingPanel extends JPanel{





public static Vector contents;


public PaintingPanel(Vector contents)
{   
    contents = new Vector();
    contents.addElement(Breakout.paddle);
    contents.addElement(Breakout.ball);



    System.out.println(contents);

}

public void paintComponent(Graphics g)
{

    super.paintComponent(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setBackground(Color.GREEN);
    g2d.drawRect(2, 2, 800, 800);
    Breakout.paddle.paintThis(g2d);
    Breakout.ball.paintThis(g2d);       
}

}

package assignment1;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;

public class Paddle {



public static int PADDLE_SIZE = 100;
public static int PADDLE_THICKNESS = 10;
public static int centreX = 400;                                // X Centre of the paddle
public static int centreY = 795;                                // Y Centre of the paddle
public static int paddleX = centreX - (PADDLE_SIZE/2);          // Top left X coordinate
public static int paddleY = centreY -(PADDLE_THICKNESS/2);      // Top left Y coordinate    
public static int dirX;


public Paddle(int paddleX, int paddleY, int PADDLE_SIZE, int PADDLE_THICKNESS)
{
    this.paddleX = paddleX;
    this.paddleY = paddleY;
    this.PADDLE_SIZE = PADDLE_SIZE;
    this.PADDLE_THICKNESS = PADDLE_THICKNESS;

    System.out.println("Paddle created at " + paddleX + ", " + paddleY + ", " + PADDLE_SIZE + ", " + PADDLE_THICKNESS);


}

public static void paintThis(Graphics g)
{
    g.setColor(Color.BLACK);
    g.fillRect(paddleX, paddleY, PADDLE_SIZE, PADDLE_THICKNESS);
    g.drawRect(paddleX, paddleY, PADDLE_SIZE, PADDLE_THICKNESS);

}

public static Rectangle getBounds()
{
    return new Rectangle(paddleX, paddleX, PADDLE_SIZE, PADDLE_THICKNESS);

}

public static void move()
{
    paddleX = paddleX + dirX;
}

public static void keyPressed(KeyEvent e) 
{

    if (e.getKeyCode() == KeyEvent.VK_LEFT)
    {
        dirX = -10;
    }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT)
    {
        dirX = 10;
    }
    else {}
}

public static void keyReleased(KeyEvent e) 
{
    dirX = 0;
}

}

package assignment1;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Random;

public class Ball {

public static int x;
public static int y;
public static int radius;
public final static Color colour = Color.RED;
public static double dirX;
public static double dirY;
public static int speed = 0;


public Ball(int x, int y, int radius)
{       
    this.x = x;
    this.y = y;
    this.radius = radius;
    dirX = 0;
    dirY = -Math.sqrt(1 - dirX*dirX);
    System.out.println("Ball created at " + x + ", " + y + ", " + dirX + ", " + dirY);
}


public static void paintThis(Graphics g)
{
    g.setColor(colour);
    int width = radius*2;
    g.fillOval(x, y, width, width);
    g.drawOval(x, y, width, width);
}


public static Rectangle getBounds()
{
    return new Rectangle(x, y, radius*2, radius*2);                     
}



public static void move()
{
    x = (int) (x-dirX*speed);           //check for inaccuracy
    y = (int) (y-dirY*speed);
    System.out.println("Moved, New X = " + x + ", new Y = "+ y);
}




public void reflect(boolean horizontal, boolean vertical)
{
    if (vertical == true)
    {
        dirX = 0-dirX;
    }
    if (horizontal == true)
    {
        dirY = 0-dirY;
    }
}


public boolean intersects(Paddle paddle) {
    if (getBounds().intersects(Paddle.getBounds())){
        return true;
    }
    else return false;
}

}

https://dl.dropboxusercontent.com/u/65678182/assignment1.rar

Answer 1

The getBounds() method in the Paddle class seems to be the problem. You are returning a Rectangle with upper left coordinates of paddleX and paddleX. I think you meant return new Rectangle(paddleX, paddleY, PADDLE_SIZE, PADDLE_THICKNESS); instead.