I am working on a 4 Way Pong Program. I have it to the point where my paddles will move with mouse movement, and the ball will bounce around the screen.
I am stuck when it comes to figuring out how to check for collisions between the ball and the paddles (which will increase the score) and between the ball and the edges of the JPanel (which will end the game).
Any guidance is greatly appreciated...
Game Class
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Game extends JPanel {
JFrame window = new JFrame();
Timer timer = new Timer(30, new ActionHandler());
ArrayList<Ball> balls = new ArrayList<Ball>();
ArrayList<Paddle> horizPaddles = new ArrayList<Paddle>();
ArrayList<Paddle> vertPaddles = new ArrayList<Paddle>();
Paddle pTop;
Paddle pBottom;
Paddle pRight;
Paddle pLeft;
Ball b;
int score = 0;
JLabel scoreLabel;
//==========================================================
public Game() {
window.setBounds(100,100,900,500);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setTitle("4 Way Pong");
window.setResizable(false);
JPanel scorePanel = new JPanel(true);
scoreLabel = new JLabel("Current Score: " + Integer.toString(score));
scoreLabel.setFont(new Font("sansserif", Font.PLAIN, 20));
scoreLabel.setForeground(Color.RED);
scorePanel.add(scoreLabel);
JPanel buttons = new JPanel(true);
Container con = window.getContentPane();
con.setLayout(new BorderLayout());
con.add(this, BorderLayout.CENTER);
con.add(buttons, BorderLayout.SOUTH);
con.add(scorePanel, BorderLayout.NORTH);
this.setBackground(Color.BLACK);
this.addMouseMotionListener(new MouseMoved());
ButtonCatch bc = new ButtonCatch();
JButton btn;
btn = new JButton("New Game");
btn.addActionListener(bc);
buttons.add(btn);
btn = new JButton("Swap Colors");
btn.addActionListener(bc);
buttons.add(btn);
btn = new JButton("High Scores");
btn.addActionListener(bc);
buttons.add(btn);
btn = new JButton("Save Score");
btn.addActionListener(bc);
buttons.add(btn);
btn = new JButton("Quit");
btn.addActionListener(bc);
buttons.add(btn);
timer.start();
window.setVisible(true);
}
//==========================================================
public static void main(String[] args) {
new Game();
}
//==========================================================
public void update() {
for(Ball b : balls) {
b.move(getWidth() + 30, getHeight() + 25);
}
//checkSideCollision();
//checkHorizPaddleCollision();
//checkVertPaddleCollision();
repaint();
}
//==========================================================
public void checkSideCollision() {
if(b.getyPos() > getHeight()) {
JOptionPane.showMessageDialog(null, "Game Over. You Scored " + score + ".", "GAME OVER", JOptionPane.INFORMATION_MESSAGE);
System.exit(0);
}
}
//==========================================================
public void checkHorizPaddleCollision() {
if(b.getxPos() == pBottom.getX() && b.getyPos() == pBottom.getY()) {
//b.yPos = b.yPos - 5;
score++;
}
}
//==========================================================
public void checkVertPaddleCollision() {
}
//==========================================================
public class ButtonCatch implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
switch(e.getActionCommand()) {
case "Quit": JOptionPane.showMessageDialog(null, "You Quit... No Score Recorded", "Game Over", JOptionPane.INFORMATION_MESSAGE); System.exit(0);
case "New Game": newGame(); break;
case "Swap Colors": swapColors(); break;
case "High Scores": try { displayScores(); } catch (Exception e1) { System.out.println(e1.getMessage()); } break;
case "Save Score": try { saveScore(); } catch (Exception e2) { System.out.println(e2.getMessage()); } break;
}
}
}
//==========================================================
public void paint(Graphics g) {
super.paint(g);
for(Ball b : balls) {
b.draw(g);
}
for(Paddle p : horizPaddles) {
p.draw((Graphics2D) g);
}
for(Paddle p : vertPaddles) {
p.draw((Graphics2D) g);
}
}
//==========================================================
//FIX FOR DISPLAYING SCORES
private void displayScores() throws Exception {
}
//==========================================================
//FIX -- Store Score in a File
private void saveScore() throws Exception {
int userScore = score;
String name = JOptionPane.showInputDialog("Enter Your Name: ");
JOptionPane.showMessageDialog(null, "Saved!\n" + name + " scored " + userScore, "Score Recorded", JOptionPane.INFORMATION_MESSAGE);
}
//==========================================================
private void swapColors() {
for(Ball b : balls) {
if(b.color.equals(Color.red)) {
b.setColor(Color.yellow);
} else if (b.color.equals(Color.yellow)) {
b.setColor(Color.blue);
} else {
b.setColor(Color.red);
}
}
}
//==========================================================
private void newGame() {
//CREATE BALL
balls.clear();
b = new Ball();
b.color = Color.red;
b.dx = (int)(Math.random() * 4) + 1;
b.dy = (int)(Math.random() * 4) + 1;
b.xPos = (int)(Math.random() * 4) + 1;
b.yPos = (int)(Math.random() * 4) + 1;
balls.add(b);
//CREATE PADDLES
horizPaddles.clear();
vertPaddles.clear();
// bottom
pBottom = new Paddle();
pBottom.x = getWidth() / 2;
pBottom.y = getHeight();
pBottom.setX(pBottom.getX()-20);
pBottom.setY(pBottom.getY()-20);
pBottom.setWidth(100);
pBottom.setHeight(20);
horizPaddles.add(pBottom);
//top
pTop = new Paddle();
pTop.x = getWidth() / 2;
pTop.y = getHeight();
pTop.setX(0 + pTop.getX());
pTop.setY(0);
pTop.setWidth(100);
pTop.setHeight(20);
horizPaddles.add(pTop);
//left
pLeft = new Paddle();
pLeft.x = getWidth() / 2;
pLeft.y = getHeight();
pLeft.setX(0);
pLeft.setY(pLeft.getY() / 2);
pLeft.setWidth(20);
pLeft.setHeight(100);
vertPaddles.add(pLeft);
//right
pRight = new Paddle();
pRight.x = getWidth() / 2;
pRight.y = getHeight();
pRight.setX(875);
pRight.setY(pRight.getY() / 2);
pRight.setWidth(20);
pRight.setHeight(100);
vertPaddles.add(pRight);
timer.start();
}
//==========================================================
public class ActionHandler implements ActionListener {
@Override
public void actionPerformed(ActionEvent arg0) {
update();
}
}
//==========================================================
public class MouseMoved implements MouseMotionListener {
@Override
public void mouseMoved(MouseEvent e) {
for(Paddle p : horizPaddles) {
p.x = e.getX();
}
for(Paddle p : vertPaddles) {
p.y = e.getY();
}
}
@Override public void mouseDragged(MouseEvent e) {}
}
}
Paddle Class
import java.awt.Color;
import java.awt.Graphics2D;
public class Paddle implements Drawable{
public int x, y, width, height;
public Paddle() {
super();
}
public Paddle(int x, int y, int width, int height) {
super();
setX(x);
setY(y);
setWidth(width);
setHeight(height);
}
@Override
public void draw(Graphics2D g) {
g.setColor(Color.green);
g.fillRect(x, y, width, height);
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
}
Ball Class
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.io.IOException;
import java.io.RandomAccessFile;
import javax.swing.JPanel;
public class Ball implements Comparable<Ball>, Cloneable{
private static int count = 0;
public static final int NAME_LENGTH = 20;
public String name = "";
public int xPos=0, yPos=0, dx = 3, dy = 2;
public Color color = Color.red;
public static void resetCounter() { count = 0; }
public Ball() {name = "Rock: " + ++count;}
public Ball(RandomAccessFile file) {
load(file);
}
public void load(RandomAccessFile file) {
try {
xPos = file.readInt();
yPos = file.readInt();
dx = file.readInt();
dy = file.readInt();
color = new Color( file.readInt() );
byte[] n = new byte[NAME_LENGTH];
file.readFully(n);
name = new String(n).trim();
System.out.println(name);
} catch (IOException e) {
e.printStackTrace();
}
}
public void save(RandomAccessFile file) {
try {
file.writeInt(xPos);
file.writeInt(yPos);
file.writeInt(dx);
file.writeInt(dy);
file.writeInt(color.getRGB());
file.writeBytes( getStringBlock(name, NAME_LENGTH) );
} catch (IOException e) {
e.printStackTrace();
}
}
private String getStringBlock(String string, int len) {
StringBuilder sb = new StringBuilder(name);
sb.setLength(len);
return sb.toString();
}
public void draw(Graphics g) {
g.setColor(color);
g.fillOval(xPos, yPos, 25, 25);
g.setColor(Color.black);
g.drawOval(xPos, yPos, 25, 25);
}
public void setColor(Color c) {
color = c;
}
public void move(int width, int height) {
xPos+=dx;
yPos+=dy;
if(xPos + 50 > width) {
xPos = width - 50;
dx = -dx;
}
if(yPos + 50 > height) {
yPos = height - 50;
dy = -dy;
}
if(xPos < 0) {
xPos = 0;
dx = -dx;
}
if(yPos < 0) {
yPos = 0;
dy = -dy;
}
}
@Override
public int compareTo(Ball arg0) {
return 0;
}
public int getxPos() {
return xPos;
}
public int getyPos() {
return yPos;
}
}
Thanks again...
For the Paddle-Ball collisions, I think calling this method on a timer might suffice:
public void checkPaddleCollisions(){
Rectangle a = new Rectangle(pTop.getX(), pTop.getY(), pTop.getWidth(), pTop.getHeight());
Rectangle b = ... //Do this for all the paddles.
Rectangle ball = new Rectangle(ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight());
if(a.intersects(ball) || b.intersects(ball) || c.intersects(ball) || d.intersects(ball)){
//Increment score and bounce ball.
}
}
As for collisions with the edge, I think you could do something similar, just create 4 rectangles representing the edges of the screen.