Develop Reference

Graphics not Showing

I'm trying to make a test application.First I made the basic things (frame, graphics, textures). When I ran the application it shows an empty window. At first I thought it was from my texture class. But when I tried to set the color black it also didn't worked. Here's my code:
package Main;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
import Audio.MusicPlayer;
import MultiThreading.ThreadPool;
import Textures.Textures;
public class Main extends Canvas implements Runnable{
private static final long serialVersionUID = 1L;
private boolean running = true;
private Thread thread;
public static Main test = new Main();
public static final int height = 842 ;
public static final int width = 595;
public static final int scale = 1;
private Textures background;
public void init(){
background = new Textures("Test paper");
System.out.println("Initiating...");
}
public void run() {
init();
System.out.println("Starting...\nReady!");
running = true;
requestFocus();
while (running) {
//System.out.println("Running...");
render();
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
stop();
}
public void render(){
BufferStrategy bs = getBufferStrategy();
if(bs == null){
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.dispose();
bs.show();
g.setColor(new Color(0, 11, 54));
g.fillRect(0, 0, width, height);
background.render(g, 100, 100);
}
private synchronized void stop() {
if (!running) return;
running = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.exit(1);
}
public static void main (String args[])
{
ThreadPool pool = new ThreadPool(2);
JFrame frame = new JFrame("Stilul gotic si stilul renascentist");
frame.add(test);
frame.setSize(width / scale, height / scale);
frame.setFocusable(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
frame.pack();
MusicPlayer audio = new MusicPlayer("J");
pool.runTask(test);
pool.runTask(audio);
pool.join();
}
}
I checked the multithreading, so it couldn't be from there (the audio file is running and I used same classes for a game). Also, in the console isn't any error...
Can anyone help me?

MouseMotionListener is not working with Canvas

This is my code so far, what I want to do is to add a new Object every time the mouse is moved, but the system is not even accessing the MouseEvent class after hours of thinking, I still am not able to figure the problem. Please Help!!
My main class:
package testing;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.util.Random;
public class Wincall extends Canvas implements Runnable {
public static final int HEIGHT = 640, WIDTH = 1080;
private WinTest w;
private Handler handler;
private ME me = new ME(this);
public Wincall(){
handler = new Handler();
w = new WinTest(WIDTH, HEIGHT, "Test", this);
}
public synchronized void run(){
while(true){
long now = System.currentTimeMillis();
this.tick();
this.render();
long after = System.currentTimeMillis();
int tt = (int) (after-now);
if(tt>5)
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Time Taken in millisecs : " + tt);
}
}
public void tick(){
handler.tick();
}
public void render(){
BufferStrategy bs = this.getBufferStrategy();
if(bs == null)
{
this.createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
//render
g.setColor(Color.BLACK);
g.fillRect(0 ,0 ,WIDTH, HEIGHT);
handler.render(g);
//render end
g.dispose();
bs.show();
}
public void addStuff(){
handler.addObject(new TestGO(me.getX(), me.getY(), 32, 32));
}
public static void main(String[] args){
new Wincall();
}
}
My MouseEvent class:
package testing;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
public class ME implements MouseMotionListener{
private int mx = 0, my = 0;
private Wincall game;
public ME(Wincall game){
this.game = game;
}
public void mouseDragged(MouseEvent e){}
public void mouseMoved(MouseEvent e) {
game.addStuff();
mx = e.getX();
my = e.getY();
System.out.println(mx);
System.out.println(my);
}
public int getX(){
return mx;
}
public int getY(){
return my;
}
}
My window class:
package testing;
import java.awt.Canvas;
import javax.swing.JFrame;
public class WinTest {
private static final long serialVersionUID = -369751247370351003L;
public WinTest(int h, int w, String title, Wincall game){
JFrame f = new JFrame(title);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(h, w);
f.add(game);
f.setVisible(true);
f.requestFocus();
f.setResizable(false);
f.setFocusable(true);
game.addMouseMotionListener(new ME());
game.run();
}
}

Though its not clear what you are trying to do. But you need to add the MouseMotionListener to canvas not to the JFrame. Since you are adding canvas to the JFrame, it is the canvas which should capture MouseEvents. Hence, your Wintest should probably look like this :
public class WinTest extends Canvas {
private static final long serialVersionUID = -369751247370351003L;
public WinTest(int h, int w, String title, Wincall game, ME me) {
JFrame f = new JFrame(title);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(h, w);
f.add(game);
f.setVisible(true);
f.requestFocus();
f.setResizable(false);
f.setFocusable(true);
// f.addMouseMotionListener(me);
game.addMouseMotionListener(me);
game.run();
}
}
Update :
Wincalll Class:
public class Wincall extends Canvas implements Runnable {
public static final int HEIGHT = 640, WIDTH = 1080;
private WinTest w;
// private Handler handler;
private ME me = new ME(this);
public Wincall() {
// handler = new Handler();
w = new WinTest(WIDTH, HEIGHT, "Test", this, me);
}
public synchronized void run() {
while (true) {
long now = System.currentTimeMillis();
this.tick();
this.render();
long after = System.currentTimeMillis();
int tt = (int) (after - now);
if (tt > 5)
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
// System.out.println("Time Taken in millisecs : " + tt);
}
}
public void tick() {
// handler.tick();
}
public void render() {
BufferStrategy bs = this.getBufferStrategy();
if (bs == null) {
this.createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
// render
g.setColor(Color.BLACK);
g.fillRect(0, 0, WIDTH, HEIGHT);
// handler.render(g);
// render end
g.dispose();
bs.show();
}
public void addStuff() {
System.out.println("addStuff");
// handler.addObject(new TestGO(me.getX(), me.getY(), 32, 32));
}
public static void main(String[] args) {
new Wincall();
}
}

I was looking at some of my old source codes:
Try
addMouseMotionListener(me);
Instead of:
f.addMouseMotionListener(me);

Why doesn't my screen turn red?

Ok, so I'm new to programming and I'm following a tutorial on Youtube to build my own game. My problem is that my screen doesn't turn red, it just stays gray. I'm sure I did something wrong but there are no errors on eclipse. Here is the code:
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
public class Game extends Canvas implements Runnable {
private static final long serialVersionUID = 1L;
public static int width = 300;
public static int height = width / 16 * 9;
public static int scale = 3;
private Thread thread;
private JFrame frame;
private boolean running = false;
public Game() {
Dimension size = new Dimension(width * scale, height * scale);
setPreferredSize(size);
frame = new JFrame();
}
public synchronized void start() {
running = true;
thread = new Thread("Display");
thread.start();
}
public synchronized void stop() {
running = false;
try {
thread.join();
} catch(InterruptedException e) {
e.printStackTrace();
}
}
public void run() {
while (running) {
update();
render();
}
}
public void update() {
}
public void render() {
BufferStrategy bs = getBufferStrategy();
if (bs == null) {
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.setColor(Color.RED);
g.fillRect(0, 0, getWidth(), getHeight());
g.dispose();
bs.show();
}
public static void main(String[] args){
Game game = new Game();
game.frame.setResizable(false);
game.frame.setTitle("JJF");
game.frame.add(game);
game.frame.pack();
game.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.frame.setLocationRelativeTo(null);
game.frame.setVisible(true);
game.start();
}
}

You never actually provide the Thread with something to run...
public synchronized void start() {
running = true;
// Not the reference to this...
thread = new Thread(this, "Display");
thread.start();
}
By passing this (which is an instance of your Game class which implements Runnable), the Thread will be able to call your run method
nb:
The size of your viewable area should be defined by the component, not the frame. This can be achieved by overriding the getPreferredSize method and returning the preferred viewable size you want the component to be. Otherwise, the viewable area will be the size of the frame minus it's decoration insets, which may not meet your expectations.
In your "game-loop" you should consider having a small delay between cycles to give time for the system to actually update the screen, this takes some of the pressure of the Thread
Runnable example
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
public class Game extends Canvas implements Runnable {
private static final long serialVersionUID = 1L;
public static int width = 300;
public static int height = width / 16 * 9;
public static int scale = 3;
private Thread thread;
private JFrame frame;
private boolean running = false;
public Game() {
Dimension size = new Dimension(width * scale, height * scale);
setPreferredSize(size);
frame = new JFrame();
}
public synchronized void start() {
running = true;
thread = new Thread(this, "Display");
thread.start();
}
public synchronized void stop() {
running = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void run() {
while (running) {
update();
render();
// try {
// Thread.sleep(40);
// } catch (InterruptedException ex) {
// }
}
}
public void update() {
}
public void render() {
BufferStrategy bs = getBufferStrategy();
if (bs == null) {
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.setColor(Color.RED);
g.fillRect(0, 0, getWidth(), getHeight());
g.dispose();
bs.show();
}
public static void main(String[] args) {
Game game = new Game();
game.frame.setResizable(false);
game.frame.setTitle("JJF");
game.frame.add(game);
game.frame.pack();
game.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.frame.setLocationRelativeTo(null);
game.frame.setVisible(true);
game.start();
}
}

drawImage error when trying to draw a sprite onto a JFrame

I have this really crappy sprite sheet that I made, which is basically just a bunch of circles and ovals so I can grasp Sprite animation.
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.*;
public class CircleSprite extends JFrame implements ActionListener, Runnable{
BufferedImage circles;
BufferedImage[] test;
Timer timer;
int cycle = 0;
Graphics g = getGraphics();
public void asd(){
setSize(500,500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
try {
circles = ImageIO.read(new File("CircleTest.png"));
} catch (IOException e) {
e.printStackTrace();
}
final int width = 206;
final int height = 206;
final int rows= 2;
final int columns = 3;
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test = new BufferedImage[rows * columns];
try{
for(int i = 0; i < rows; i++)
for(int j = 0;j<columns;j++)
{
test[i*columns + j] = circles.getSubimage(j * width, i * height, width, height);
}
}catch(Exception e){
e.printStackTrace();
}
timer = new Timer(500, this);
setVisible(true);
}
public void actionPerformed(ActionEvent e){
//0, 1, 2, 3, 4, 5, 4, 3, 2, 1, 0, 1, 2, etc.
repaint();
g.drawImage(test[cycle], 25, 25, null);
if(cycle >= 5){
cycle--;
}
if(cycle <=0){
cycle++;
}
}
public void run(){
asd();
while(timer.isRunning() == false && this.isVisible() == true){
timer.start();
try {
CircleSpriteRun.t1.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
The error occurs here: g.drawImage(test[cycle], 25, 25, null);
At first I though it had to do with the ImageObserver being null, and looking further into it, I was wrong. Now, I think it might be because of the timer, but I don't really know too much about Timers, let alone the swing one.
This all runs on a Thread being executed in another class, and it could also have to do with the while statement in the run method, since that also involves the timer.

Since you didn't provide a runnable example, I created one to show how to properly code a Swing application.
First, you must start a Swing application with the SwingUtilities.invokeLater method. Here's how I started the CircleSprite class.
public static void main(String[] args) {
SwingUtilities.invokeLater(new CircleSprite());
}
Second, you should use a JPanel for drawing, not a JFrame. Here's the DrawingPanel I created. My version of CircleSprite draws a circle in a random location every 2 seconds.
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = -4603711384104715819L;
private int x;
private int y;
private BufferedImage image;
public DrawingPanel(BufferedImage image) {
this.image = image;
this.x = 0;
this.y = 0;
setPreferredSize(new Dimension(500, 500));
}
public void setPoint(int x, int y) {
this.x = x;
this.y = y;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, x, y, null);
}
}
Third, you create the Swing GUI before you do anything with the Swing GUI. Here's the run method from the CircleSprite class. I create the GUI, then I start the thread that does the random drawing.
public void run() {
circle = createCircle();
frame = new JFrame("Circle Sprite");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel(circle);
frame.add(drawingPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
new Thread(new RandomDraw(drawingPanel)).start();
}
Fourth, you only extend a Swing component when you want to override a method, like I did in the DraawingPanel class. You use Swing Components otherwise.
Here's the entire, runnable, CircleSprite class. You can use this as a model for future Swing applications.
package com.ggl.testing;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class CircleSprite implements Runnable {
private BufferedImage circle;
private DrawingPanel drawingPanel;
private JFrame frame;
#Override
public void run() {
circle = createCircle();
frame = new JFrame("Circle Sprite");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel(circle);
frame.add(drawingPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
new Thread(new RandomDraw(drawingPanel)).start();
}
private BufferedImage createCircle() {
BufferedImage image = new BufferedImage(100, 100,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, 100, 100);
g.setColor(Color.BLUE);
g.fillOval(10, 10, 80, 80);
g.dispose();
return image;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new CircleSprite());
}
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = -4603711384104715819L;
private int x;
private int y;
private BufferedImage image;
public DrawingPanel(BufferedImage image) {
this.image = image;
this.x = 0;
this.y = 0;
setPreferredSize(new Dimension(500, 500));
}
public void setPoint(int x, int y) {
this.x = x;
this.y = y;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, x, y, null);
}
}
public class RandomDraw implements Runnable {
private DrawingPanel drawingPanel;
private Random random;
public RandomDraw(DrawingPanel drawingPanel) {
this.drawingPanel = drawingPanel;
this.random = new Random();
}
#Override
public void run() {
while (true) {
sleep();
int x = random.nextInt(400);
int y = random.nextInt(400);
drawingPanel.setPoint(x, y);
}
}
private void sleep() {
try {
Thread.sleep(2000L);
} catch (InterruptedException e) {
}
}
}
}

Exception in thread "Display" java.lang.ArrayIndexOutOfBoundsException: 48600

I've been getting this error when I run my game, not debug it for some reason :/ If anyone can help me with this bug than I'd greatly appreciate it, here's the error: (I'm new to the website)
Exception in thread "Display" java.lang.ArrayIndexOutOfBoundsException: 48600
at com.cmnatic.IndieFirstStudios.Game.render(Game.java:78)
at com.cmnatic.IndieFirstStudios.Game.run(Game.java:60)
at java.lang.Thread.run(Unknown Source)
Here is my code :
package com.cmnatic.IndieFirstStudios;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import javax.swing.JFrame;
import com.cmnatic.IndieFirstStudios.graphics.Screen;
public class Game extends Canvas implements Runnable {
/**
*
*/
private static final long serialVersionUID = 1L;
public static int width = 300;
public static int height = width / 16 * 9;
public static int scale = 3;
private Thread thread;
private JFrame frame;
private boolean running = false;
private Screen screen;
private BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
private int[] pixels = ((DataBufferInt)image.getRaster().getDataBuffer()).getData();
public Game() {
Dimension size = new Dimension(width * scale, height * scale);
setPreferredSize(size);
screen = new Screen(width, height);
frame = new JFrame();
}
public synchronized void start() {
running = true;
thread = new Thread(this, "Display");
thread.start();
}
public synchronized void stop() {
running = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void run() {
while (running == true) {
update();
render();
}
}
public void update() {
}
public void render() {
BufferStrategy bs = getBufferStrategy();
if (bs == null) {
createBufferStrategy(3);
return;
}
screen.render();
for (int i = 0; 1 < pixels.length; i++) {
pixels[i] = screen.pixels[i];
}
Graphics g = bs.getDrawGraphics();
g.setColor(Color.BLACK);
g.fillRect(0, 0, getWidth(), getHeight());
g.drawImage(image, 0, 0, getWidth(), getHeight(), null);
g.dispose();
bs.show();
}
public static void main(String[] args) {
Game game = new Game();
game.frame.setResizable(false);
game.frame.setTitle("Fallen Humanity");
game.frame.add(game);
game.frame.pack();
game.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.frame.setLocationRelativeTo(null);
game.frame.setVisible(true);
game.start();
}
}

You have an infinite loop at line 78. Your saying run through the for loop if 1(one) < pixel.length. So eventually i will be > pixel.length

Just change the loop to:
for (int i = 0; i < pixels.length; i++) {
pixels[i] = screen.pixels[i];
}