I am trying to code the game Pong on Java but am having difficulty displaying the graphics. Nothing appears, just a blank gray default screen when I try to run the program. I am using a Mac, and am running this code on Eclipse.
Any help would be much appreciated.
Thank you.
"Pong.java"
package pong;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.Timer;
public class Pong implements ActionListener{
public static Pong pong;
public int width = 700, height = 700;
public Renderer renderer;
public Paddle player1;
public Paddle player2;
public JFrame jframe;
public Pong(){
Timer timer = new Timer(20, this);
jframe = new JFrame("Pong");
renderer = new Renderer();
jframe.setSize(width, height);
jframe.setVisible(true);
jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jframe.add(renderer);
start();
timer.start();
}
public void start(){
player1 = new Paddle(this, 1);
player2 = new Paddle(this, 2);
}
public void update() {
}
public void render(Graphics g) {
g.setColor(Color.BLACK);
g.fillRect(0, 0, width, height);
player1.render(g);
player2.render(g);
}
#Override
public void actionPerformed(ActionEvent e) {
update();
renderer.repaint();
}
public static void main(String[] args){
pong = new Pong();
}
}
"Renderer.java"
package pong;
import java.awt.Graphics;
import javax.swing.JPanel;
public class Renderer extends JPanel {
private static final long serialVersionUID = 1L;
#Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
Pong.pong.render(g);
}
}
"Paddle.java"
package pong;
import java.awt.Color;
import java.awt.Graphics;
public class Paddle {
public int paddleNumber;
public int x, y, width = 100, height = 500;
public int score;
public Paddle(Pong pong, int paddleNumber){
this.paddleNumber = paddleNumber;
if(paddleNumber == 1){
this.x = 0;
}
else if (paddleNumber == 2){
this.x = pong.width - width;
}
this.y = pong.height / 2 - this.height / 2;
}
public void render(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(x, y, width, height);
}
}
Related
I am loosely following this persons code to make a pong game
However, when I run the program, the screen will either, 1. turn plain white, 2. Turn white and then paint to the screen a couple seconds later, or 3. paint to the screen immediately.
I don't have very much code currently. Why is there sometimes a delay when painting to my frame? how can I fix this? is there a better way to do this?
[Main class]
import javax.swing.JFrame;
public class Main extends JFrame {
public static final int FRAME_WIDTH = 900, FRAME_HEIGHT = 500;
GamePanel game;
public Main() {
this.setTitle("Pong");
this.setSize(FRAME_WIDTH, FRAME_HEIGHT);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setVisible(true);
game = new GamePanel(this);
add(game);
}
public static void main(String[] args) {
Main main = new Main();
}
public int getWidth() {
return FRAME_WIDTH;
}
public int getHeight() {
return FRAME_HEIGHT;
}
}
[Game Panel]
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import javax.swing.JPanel;
public class GamePanel extends JPanel {
private Main main;
private Player player;
private int playerScore = 0;
private int oppScore = 0;
private int yCenter;
public GamePanel(Main main) {
setBackground(Color.BLACK);
this.main = main;
this.yCenter = (main.getHeight() / 2) - 75;
player = new Player(main, 25, yCenter);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.WHITE);
g.setFont(new Font("Courier", Font.BOLD, 40));
g.drawString(playerScore + " - " + oppScore, (main.getWidth() / 2) - 75, 50);
player.draw(g);
}
}
[Player Class]
import java.awt.Graphics;
public class Player {
private Main main;
private static final int PLAYER_WIDTH = 30, PLAYER_HEIGHT = 125;
private int x, y;
public Player(Main main, int x, int y) {
this.main = main;
this.x = x;
this.y = y;
}
public void draw(Graphics g) {
g.fillRect(x, y, PLAYER_WIDTH, PLAYER_HEIGHT);
}
}
Howcome this code below wont work? I want to add new Ovals to the ArrayList every 200 ms and display them and run them one by one. It works fine when Im running one particle s.runner(); but it doesnt seem to run all my particles.
MAIN:
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.Timer;
public class ExempelGraphics extends JFrame implements ActionListener {
Timer t;
private int inc = 0;
ArrayList<Surface> particle = new ArrayList<>();
Surface s;
public ExempelGraphics() {
t = new Timer(10, this);
t.start();
s = new Surface(10, 10);
initUI();
}
private void initUI() {
add(s);
setSize(350, 250);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e) {
// s.runner();
// add
if (inc++ % 20 == 0) {
particle.add(new Surface(10, 10));
}
// display
for (int i = 0; i < particle.size(); i++) {
Surface p = particle.get(i);
p.runner();
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ExempelGraphics ex = new ExempelGraphics();
ex.setVisible(true);
}
});
}
}
GRAPHICS:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
public class Surface extends JPanel {
private int locX = 0;
private int locY = 0;
public Surface(int locX, int locY) {
this.locX = locX;
this.locY = locY;
}
public void runner() {
locX = locX + 1;
repaint();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.RED);
g2d.fillOval(locX, locY, 10, 10);
}
}
I think that you're program structure is broken. You should have only one JPanel here that does the drawing, that has its paintComponent overridden, and your Surface class should be a logical class and not a component class -- in other words, don't have it extend JPanel, and give it a public void draw(Graphics g) method where you draw the oval. Then have the drawing JPanel hold an ArrayList of these surfaces, and in the main JPanel's paintComponent method, iterate through the surfaces, calling each one's draw method.
Also your Timer's delay is not realistic and is too small. 15 would be much more realistic.
Also, don't call repaint() from within surface, since that will generate too many repaint calls unnecessarily. Instead call it from within the Timer's ActionListener after calling the runner methods on all the Surface objects.
Also note that every time you add a component to a JFrame's contentPane in a default fashion, you cover up the previously added components. If you go by my recommendations above, this isn't an issue since you'd only be adding that single JPanel to it.
For example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
#SuppressWarnings("serial")
public class ExampleGraphics2 extends JPanel {
private static final int PREF_W = 650;
private static final int PREF_H = 500;
private static final int TIMER_DELAY = 20;
private List<Surface> surfaces = new ArrayList<>();
public ExampleGraphics2() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
for (Surface surface : surfaces) {
surface.draw(g);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
private int index = 0;
#Override
public void actionPerformed(ActionEvent e) {
index++;
index %= 20;
if (index == 0) {
surfaces.add(new Surface(10, 10));
}
for (Surface surface : surfaces) {
surface.runner();
}
repaint();
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("Example Graphics 2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ExampleGraphics2());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
package foo1;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
public class Surface {
private int locX = 0;
private int locY = 0;
public Surface(int locX, int locY) {
this.locX = locX;
this.locY = locY;
}
public void runner() {
locX = locX + 1;
}
public void draw(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.RED);
g2d.fillOval(locX, locY, 10, 10);
}
}
I want to Color 2 Ovals in Java with Graphics2D. Oval1(point) Green and Oval2(point2) Blue. The Problem is that Oval2 becomes green and Oval1 black. Does somebody knows what the problem is?
left(oval1) right(oval2)
Here is the SSCCE:
GameView.java
import javax.swing.JFrame;
import stackoverflow.GameView;
public class GameView extends JFrame{
/**
*
*/
private static final long serialVersionUID = 1L;
private Game game = new Game();
public GameView(){
JFrame gameFrame = new JFrame("Game");
gameFrame.setSize(500, 300);
gameFrame.setVisible(true);
gameFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
gameFrame.add(game);
game.runGame();
}
public static void main(String[] args) throws InterruptedException {
new GameView();
}
}
Game.java
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
import stackoverflow.Point;
public class Game extends JPanel{
/**
*
*/
private static final long serialVersionUID = 1L;
private Point point = new Point(Color.GREEN);
private Point point2 = new Point(Color.BLUE);
public void runGame(){
repaint();
point2.setX(300);
}
public void paint(Graphics g) {
point.paint(g);
point2.paint(g);
}
}
Point.java
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
public class Point {
private int x = 100;
private int y = 100;
private int width = 10;
private int height = 10;
private Color color;
public Point(Color color){
this.color = color;
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.fillOval(x, y, width, height);
g2d.setColor(this.color);
}
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;
}
}
Change the order of these calls...
g2d.fillOval(x, y, width, height);
g2d.setColor(this.color);
And you should be painting in JPanel.paintComponent instead.
I was programming a game similar to asteroid, but I do not understand how to spawn the asteroids in the background.
now i spawn an asteroid in the main class but i want create a class for the asteroid ho i do it?
MAIN CLASS
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
if(flag_img)
{
background(g2d);
logo(g2d);
menu(g2d);
spaceship(g2d);
crediti(g2d);
}
}
background function(now)
private void background(Graphics2D g2d)
{
asteroidi_g_x+=r.nextInt(4);
asteroidi_g_y+=r.nextInt(1);
g2d.drawImage(asteroidi_g[0], asteroidi_g_x,asteroidi_g_y,this);
}
background function(what i want)
private void background(Graphics2D g2d)
{
asteroid asteroid = new asteroid[10];
}
and class asteroid
public class asteroid extends JPanel implements ActionListener
{
private BufferedImage images_asteroid;
private boolean flag_img;
private JPanel jp;
private int x,y;
public asteroide_grande(JPanel jp)
{
flag_img = true;
x = (jp.getWidth()/2);
y = (jp.getHeight()/2);
this.jp = jp;
try {
images_asterod = ImageIO.read(this.getClass().getResource("images/asteroid/a1.png"));
} catch(IOException e){flag = false;}
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
if(flag_img)
{
g.drawImage(images_asteroid, 100, 100,this);
}
}
#Override
public void actionPerformed(ActionEvent e)
{
x=x-1;
y=y+1;
repaint();
}
method paintcomponent in class doesn't work
Don't have your Asteroid class extends JPanel. Instead have it as a class that model's asteroid data and has data manipulation methods. You'll also want to have a draw method that take a Graphic context. Something like
public class Asteroid {
Image asteroidImage;
JPanel panel;
int x, y;
public Asteroid(JPanel panel, Image image, int x, int y) {
this.panel = panel;
this.asteroidImage = image;
this.x = x;
this.y = y;
}
public void drawAsteroid(Graphics g) {
g.drawImage(asteroidImage, x, y, panel);
}
public void move() {
x += 5;
}
}
Now you have a model of an asteroid, you can create a List of Asteriod objects and iterate through them and use it's drawAsteroid method to paint them. Something like
public class GamePanel extends JPanel {
List<Asteroid> asteroids;
Image asteroidImage;
public GamePanel(){
asteroidImage = ...
asteroids = new ArrayList<>();
asteroids.add(new Asteroid(GamePanel.this, asteroidImage, 100, 100));
// add more asteriods
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Asteriod asteroid: asteriods) {
asteriod.drawAsteroid(g);
}
}
}
To animate them, you'll want to use a javax.swing.Timer. See more at How to Use Swing Timers. You'll want to manipulate the Asteriod data in the Timer. With the code provided above, you can just call it's move method, then call repaint(). Something like
public GamePanel(){
...
Timer timer = new Timer(30, new ActionListener(){
public void actionPerformed(ActionEvent e) {
Iterator it = asteroids.iterator();
while (it.hasNaext()) {
Asteroid asteriod = (Asteroid)it.next();
asteroid.move();
}
}
});
}
You can see a bunch more complete example of animating multiple objects here and here and here and here and here
Here's a full example. You'll see I included a Rectangle2D object in the Astreroid class. That's just if you want to check for collision detection. You should move the Rectangle2D x and/or y with every Asreroid movement of x and y. Then you can check if asteroid.rectangle.intersects(someOtherObject)
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class AsteroidBackground extends JPanel {
private static final int D_W = 400;
private static final int D_H = 600;
BufferedImage asteroidImage;
BufferedImage background;
List<Asteroid> asteroids;
Random random = new Random();
int countToAddAsteroid = 0;
int y;
public AsteroidBackground() {
try {
asteroidImage = ImageIO.read(getClass().getResource("/resources/small-asteroid.png"));
background = ImageIO.read(getClass().getResource("/resources/space.png"));
} catch (IOException ex) {
Logger.getLogger(AsteroidBackground.class.getName()).log(Level.SEVERE, null, ex);
}
asteroids = new ArrayList<>();
y = 0 - asteroidImage.getHeight();
Timer timer = new Timer(40, new ActionListener(){
public void actionPerformed(ActionEvent e) {
if (countToAddAsteroid >= 25) {
int randX = random.nextInt(D_W);
asteroids.add(new Asteroid(AsteroidBackground.this, asteroidImage, randX, y));
countToAddAsteroid = 0;
}
countToAddAsteroid++;
Iterator it = asteroids.iterator();
while (it.hasNext()) {
Asteroid asteroid = (Asteroid)it.next();
if (asteroid.y >= D_H) {
it.remove();
} else {
asteroid.move();
}
}
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background, 0, 0, this);
for (Asteroid asteroid : asteroids) {
asteroid.drawAsteroid(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
public class Asteroid {
Rectangle2D rectangle;
Image asteroidImage;
JPanel panel;
int x, y;
public Asteroid(JPanel panel, Image image, int x, int y) {
this.panel = panel;
this.asteroidImage = image;
this.x = x;
this.y = y;
rectangle = new Rectangle2D.Double(
x, y, image.getWidth(panel), image.getHeight(panel));
}
public void drawAsteroid(Graphics g) {
g.drawImage(asteroidImage, x, y, panel);
}
public void move() {
y += 5;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.add(new AsteroidBackground());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
I've been trying to do this assignment and for it to work I need the event mousePressed to work but for some reason it's not responding to the mouse. Its purpose is to paint another yellow circle when the mouse is pressed.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;
public class CatchMonster extends JPanel
{
private int height = 300;
private int width = 600;
private final int delay = 4001;
private ImageIcon image;
private Timer timer;
private int x, y, moveX, moveY, xPoint, yPoint;
public CatchMonster() {
DotListener dot = new DotListener();
addMouseListener(dot);
timer = new Timer(delay, new timerListener());
x = 40;
y = 40;
moveX = moveY = 3;
setPreferredSize(new Dimension(width, height));
setBackground(Color.black);
timer.start();
}
public void paintComponent(Graphics g) {
super.paintComponents(g);
g.setColor(Color.yellow);
g.fillOval(x, y, 60, 60);
}
private class timerListener implements ActionListener
{
public void actionPerformed(ActionEvent e) {
Random gn = new Random();
x = gn.nextInt(width);
y = gn.nextInt(height);
repaint();
}
}
private class DotListener implements MouseListener
{
public void mousePressed(MouseEvent event)
{
repaint();
}
#Override
public void mouseClicked(MouseEvent event) {
}
#Override
public void mouseEntered(MouseEvent event) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent event) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent event) {
// TODO Auto-generated method stub
}
}
}
I need the event mousePressed to work but for some reason it's not responding to the mouse. Its purpose is to paint another yellow circle when the mouse is pressed.
But it won't paint another circle as all it does is call repaint(), and how is that going to paint anything new? If you want it to create another circle, you'll have to give it logic to do so. For instance, if you want to paint more than one yellow oval, you'll want to create an ArrayList of Point objects and add a Point into that array list in the mousePressed method. Then in the paintComponent method, you can iterate through the array list, painting ovals for each Point it contains.
In addition, you want to change this:
public void paintComponent(Graphics g) {
super.paintComponents(g); // this is not the "super" method of paintComponent
g.setColor(Color.yellow);
g.fillOval(x, y, 60, 60);
}
to this:
public void paintComponent(Graphics g) {
super.paintComponent(g); // See the difference?
g.setColor(Color.yellow);
g.fillOval(x, y, 60, 60);
}
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class CatchMonster extends JPanel {
private int height = 300;
private int width = 600;
private final int delay = 4001;
private ImageIcon image;
private Timer timer;
private int x, y, moveX, moveY, xPoint, yPoint;
private List<Point> points = new ArrayList<Point>();
public CatchMonster() {
DotListener dot = new DotListener();
addMouseListener(dot);
timer = new Timer(delay, new timerListener());
x = 40;
y = 40;
moveX = moveY = 3;
setPreferredSize(new Dimension(width, height));
setBackground(Color.black);
timer.start();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.yellow);
g.fillOval(x, y, 60, 60);
int radius = 30;
g.setColor(Color.green);
for (Point p : points) {
int x = p.x - radius;
int y = p.y - radius;
g.fillOval(x, y, 2 * radius, 2 * radius);
}
}
private class timerListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
Random gn = new Random();
x = gn.nextInt(width);
y = gn.nextInt(height);
repaint();
}
}
public static void main(String[] args) {
JFrame frame = new JFrame("Foo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new CatchMonster());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private class DotListener extends MouseAdapter {
public void mousePressed(MouseEvent event) {
points.add(event.getPoint());
repaint();
}
}
}