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Graphics Stuttering in Java (Space Invaders)

I am creating a Space Invaders Game with just one Invader. The images are stuttering and are only visible ~10% of the time. What is wrong with my code?
package spaceinvader;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class spaceInvaders extends JApplet implements KeyListener, ActionListener
{
//Declare components and variables
JPanel mainPanel = new JPanel();
ImageIcon carImage = new ImageIcon("ship.png");
ImageIcon invaderImage = new ImageIcon("invader.png");
int intPosX = 240;
int intPosY = 330;
int intXAmount = 15;
boolean shipMoveLeft = false;
boolean shipMoveRight = false;
Timer shipTimer = new Timer(100,this);
int intBulletX = -50;
int intBulletY = -50;
boolean bulletMove = false;
boolean bulletActive = false;
Timer bulletTimer = new Timer(50,this);
int intInvaderX = 0;
int intInvaderY = 0;
int invaderXAmount = 10;
boolean invaderMove = true;
Timer invaderTimer= new Timer(1000,this);
public void init()
{
addKeyListener(this);
setFocusable(true);
resize(600,400);
setContentPane(mainPanel);
shipTimer.start();
bulletTimer.start();
invaderTimer.start();
}
public void actionPerformed(ActionEvent e)
{
requestFocus();
if(shipMoveLeft)
intPosX += intXAmount;
else if(shipMoveRight)
intPosX -= intXAmount;
if(bulletMove && bulletActive){
intBulletY -= 15;
if(intBulletY <= -50){
bulletMove = false;
bulletActive = false;
}
}
if(invaderMove){
intInvaderX += invaderXAmount;
if(intInvaderX > getWidth() - 60 || intInvaderX < 0){
intInvaderY += 40;
invaderXAmount *= -1;
}
}
repaint();
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if (key == 37){
shipMoveRight = true;
}
else if (key == 39){
shipMoveLeft = true;
}
else if (key == 32){
if(bulletActive == false){
intBulletX = intPosX;
intBulletY = intPosY;
}
bulletMove = true;
bulletActive = true;
}
}
public void keyReleased(KeyEvent e)
{
shipMoveLeft = false;
shipMoveRight = false;
}
public void keyTyped(KeyEvent e)
{
}
public void paint(Graphics gr)
{
super.paint(gr);
gr.setColor(Color.red);
gr.fillOval(intBulletX, intBulletY, 10, 25);
carImage.paintIcon(this,gr, intPosX, intPosY); //Draw image in new spot
invaderImage.paintIcon(this,gr, intInvaderX, intInvaderY);
}
}

So there are a number of issues which jump out immediately...
Applets are a dead end, most browsers will actively block them and/or have dropped support for the plugin
You're adding a JPanel to the applet, but overriding the applet's paint method, because of the way painting can work, the panel can be painted independently of the applet, causing it to paint over whatever you might have painted
You don't need multiple timers, you just need to have better delta values (smaller been faster)
KeyListener is a poor choice for detecting keyboard input, it's rather low level and has focus related issues which are easily overcome by using the Key Bindings API
I'd start by having a look at Performing Custom Painting, Painting in AWT and Swing and How to Use Key Bindings for more details.
So how would you start fixing it? Start by using a JPanel as you basic container, override it's paintComponent and place all your paint logic here.
Use a single Timer to manage the updates
There are any number of approaches you can take, but I'd start with defining some contracts that define what can go on in the game
public interface GameSpace extends ImageObserver {
public Dimension getGameSpace();
public boolean hasInput(Input input);
}
public interface Entity {
public void paint(GameSpace gameSpace, Graphics2D g2d);
public boolean update(GameSpace gameSpace);
public Rectangle getBounds();
}
public abstract class AbstractEntity implements Entity {
private int x;
private int y;
public int getX() {
return x;
}
public int getY() {
return y;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
protected abstract int getWidth();
protected abstract int getHeight();
public Rectangle getBounds() {
return new Rectangle(getX(), getY(), getWidth(), getHeight());
}
}
public abstract class AbstractImageEntity extends AbstractEntity {
protected abstract BufferedImage getImage();
#Override
protected int getWidth() {
return getImage().getWidth();
}
#Override
protected int getHeight() {
return getImage().getHeight();
}
}
This separates some of management of key elements, allowing for a more flexible design. You might have a lot more entities, one's which could move, ones which could not, some which are painted, some which are not, but all which provide support for the core engine to get work done.
Once you have that you can start defining some core entities you need
public class ShipEntity extends AbstractImageEntity {
private BufferedImage ship;
public ShipEntity(GameSpace gameSpace) throws IOException {
ship = ImageIO.read(getClass().getResource("/resources/ship.png"));
setY(gameSpace.getGameSpace().height - getBounds().height);
setX((gameSpace.getGameSpace().width - getBounds().width) / 2);
}
#Override
public BufferedImage getImage() {
return ship;
}
#Override
public void paint(GameSpace gameSpace, Graphics2D g2d) {
g2d.drawImage(ship, getX(), getY(), gameSpace);
}
#Override
public boolean update(GameSpace gameSpace) {
int x = getX();
if (gameSpace.hasInput(Input.LEFT)) {
x -= 2;
}
if (gameSpace.hasInput(Input.RIGHT)) {
x += 2;
}
if (x < 0) {
x = 0;
} else if (x + getWidth() > gameSpace.getGameSpace().width) {
x = gameSpace.getGameSpace().width - getWidth();
}
setX(x);
return true;
}
}
public class InvaderEntity extends AbstractImageEntity {
private BufferedImage invader;
public InvaderEntity() throws IOException {
invader = ImageIO.read(getClass().getResource("/resources/Invader.png"));
}
#Override
protected BufferedImage getImage() {
return invader;
}
#Override
public void paint(GameSpace gameSpace, Graphics2D g2d) {
g2d.drawImage(invader, getX(), getY(), gameSpace);
}
#Override
public boolean update(GameSpace gameSpace) {
return true;
}
}
public class ProjectileEntity extends AbstractEntity {
private int delta;
public ProjectileEntity(int delta) {
this.delta = delta;
}
#Override
protected int getWidth() {
return 10;
}
#Override
protected int getHeight() {
return 10;
}
#Override
public void paint(GameSpace gameSpace, Graphics2D g2d) {
g2d.setColor(Color.RED);
int width = getWidth();
int height = getHeight();
g2d.fillOval(getX() - width / 2, getY() - height / 2, width, height);
}
#Override
public boolean update(GameSpace gameSpace) {
int y = getY() + delta;
setY(getY() + delta);
return y + getHeight() >= 0 && y + getHeight() <= gameSpace.getGameSpace().height;
}
}
Basically, they contain the logic required for getting their jobs done.
Finally, you need to setup the actual game UI
public class GamePane extends JPanel implements GameSpace {
private Set<Input> inputs;
private Entity playerEntity;
private List<Entity> projectileEntities;
private List<Entity> invaderEntities;
private long timeOfLastProjectile = -1;
public GamePane() throws IOException {
setBackground(Color.BLACK);
inputs = new HashSet<>(2);
playerEntity = new ShipEntity(this);
projectileEntities = new ArrayList<>(25);
invaderEntities = new ArrayList<>(25);
InvaderEntity invader = new InvaderEntity();
invader.setX((getGameSpace().width - invader.getBounds().width) / 2);
invader.setY((getGameSpace().height - invader.getBounds().height) / 2);
invaderEntities.add(invader);
addKeyBinding(Input.LEFT, "left", KeyEvent.VK_LEFT);
addKeyBinding(Input.RIGHT, "right", KeyEvent.VK_RIGHT);
addKeyBinding(Input.SPACE, "space", KeyEvent.VK_SPACE);
Timer timer = new Timer(15, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
updateState();
processCollisions();
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void updateState() {
playerEntity.update(this);
if (hasInput(Input.SPACE)) {
long time = System.currentTimeMillis() - timeOfLastProjectile;
if (time < 0 || time > 1000) {
timeOfLastProjectile = System.currentTimeMillis();
Rectangle bounds = playerEntity.getBounds();
ProjectileEntity projectile = new ProjectileEntity(-1);
int x = bounds.x + ((bounds.width - projectile.getWidth()) / 2);
int y = bounds.y - projectile.getHeight();
projectile.setX(x);
projectile.setY(y);
projectileEntities.add(projectile);
}
}
for (Entity entity : invaderEntities) {
entity.update(this);
}
List<Entity> outOfBounds = new ArrayList<>(25);
for (Entity entity : projectileEntities) {
if (!entity.update(this)) {
outOfBounds.add(entity);
}
}
projectileEntities.removeAll(outOfBounds);
}
protected void processCollisions() {
Set<Entity> hitInvaders = new HashSet<>(25);
Set<Entity> hitProjectiles = new HashSet<>(25);
for (Entity invader : invaderEntities) {
for (Entity projectile : projectileEntities) {
if (projectile.getBounds().intersects(invader.getBounds())) {
// Maybe lots of cool explosiions
hitInvaders.add(invader);
hitProjectiles.add(projectile);
}
}
}
invaderEntities.removeAll(hitInvaders);
projectileEntities.removeAll(hitProjectiles);
}
protected void addKeyBinding(Input input, String name, int virtualKey) {
ActionMap am = getActionMap();
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
im.put(KeyStroke.getKeyStroke(virtualKey, 0, false), name + ".pressed");
im.put(KeyStroke.getKeyStroke(virtualKey, 0, true), name + ".released");
am.put(name + ".pressed", new KeyAction(inputs, input, true));
am.put(name + ".released", new KeyAction(inputs, input, false));
}
#Override
public Dimension getGameSpace() {
return getPreferredSize();
}
#Override
public boolean hasInput(Input input) {
return inputs.contains(input);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
playerEntity.paint(this, g2d);
g2d.dispose();
for (Entity entity : invaderEntities) {
g2d = (Graphics2D) g.create();
entity.paint(this, g2d);
g2d.dispose();
}
for (Entity entity : projectileEntities) {
g2d = (Graphics2D) g.create();
entity.paint(this, g2d);
g2d.dispose();
}
}
}
public class KeyAction extends AbstractAction {
private Input input;
private Set<Input> inputs;
private boolean pressed;
public KeyAction(Set<Input> inputs, Input input, boolean pressed) {
this.input = input;
this.inputs = inputs;
this.pressed = pressed;
}
#Override
public void actionPerformed(ActionEvent e) {
if (pressed) {
inputs.add(input);
} else {
inputs.remove(input);
}
}
}
Now you could go a little further and generate an "engine" class which controls the entities and performs all the required updating, but I'm lazy ;)
That's a really rough idea of some the basic concepts you need to develop to be able to move forward, hope it helps

Drawing pen strokes using java swing...strokes don't show up

So I have two classes here:
PhotoComponent class:
(This class is to handle a specific image as a JComponent. When "flipped" I want to draw pen strokes instead of having an image. So I replace the image with a rectangle, attempting to draw pen strokes over it.)
public class PhotoComponent extends JComponent {
private Image pic;
private boolean flipped;
private int contentAreaWidth;
private int contentAreaHeight;
p
#Override
public void paintComponent(Graphics g) {
//Does all the drawing and contains whatever state information is associated with the photo
//create an action event to auto call repaint
//call repaint anytime flip was changed to true or false
System.out.println("Draw: " + draw + ", Pic: " + pic);
if (draw && pic != null) {
super.paintComponent(g);
System.out.println("width using this: " + this.getWidth() + ", actual width of JPanel: " + contentAreaWidth);
System.out.println("height using this: " + this.getHeight() + ", actual height of JPanel: " + contentAreaHeight);
g2 = (Graphics2D) g;
int x = (contentAreaWidth - pic.getWidth(null)) / 2;
int y = (contentAreaHeight - pic.getHeight(null)) / 2;
if (!flipped) {
g2.drawImage(pic, x, y, null);
} else if (flipped) {
g2.setColor(Color.WHITE);
g2.fillRect(x,y,pic.getWidth(null), pic.getHeight(null));
g2.drawRect(x, y, pic.getWidth(null), pic.getHeight(null));
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (drawingMode) {
g2.setPaint(Color.RED);
if (drawOval) {
penStrokes.put(ovalX, ovalY);
if (penStrokes != null) {
for (Integer xCoor : penStrokes.keySet()) {
g2.setPaint(Color.RED);
int brushSize = 5;
g2.fillOval((xCoor - (brushSize / 2)), (penStrokes.get(xCoor) - (brushSize / 2)), brushSize, brushSize);
//System.out.println("SIZE OF HASHTABLE: " + penStrokes.size());
}
}
System.out.println("Filling an oval!" + ovalX + ", " + ovalY);
}
} else if (textMode) {
g2.setPaint(Color.YELLOW);
if (drawRect) {
rectDimensions.add(rectX);
rectDimensions.add(rectY);
rectDimensions.add(rectWidth);
rectDimensions.add(rectHeight);
for (int i = 0; i < rectDimensions.size(); i+=4) {
g2.fillRect(rectDimensions.get(i), rectDimensions.get(i+1), rectDimensions.get(i+2), rectDimensions.get(i+3));
g2.drawRect(rectDimensions.get(i), rectDimensions.get(i+1), rectDimensions.get(i+2), rectDimensions.get(i+3));
}
}
}
System.out.println("This is being called again!");
}
}
}
public void setRectangle(int x, int y, int width, int height) {
drawRect = true;
rectX = x;
rectY = y;
rectWidth = width;
rectHeight = height;
}
public void removeRectangle() {
drawRect = false;
}
public int[] setOval(int currentX, int currentY) {
drawOval = true;
int[] toReturn = {ovalX, ovalY};
ovalX =
NOTE THE DRAWLINE() METHOD ABOVE. I am drawing at the given points, repainting, and setting the old variables to be the current variables.
Main class:
private static PhotoComponent img;
private static JFrame frame;
private static JPanel contentArea;
//Mouse Coordinates for PenStrokes
private static int oldX, oldY;
//Mouse Coordinates for Sticky Notes
private static Point clickPoint;
public static void main (String[] args) {
frame = new JFrame("PhotoManip");
img = null;
contentArea = null;
oldX = 0;
oldY = 0;
setupMenubar(frame);
setupJFrame(frame);
}
private static void addPhotoComponent(File file) {
}
if (img.getTextMode()) {
img.removeRectangle();
clickPoint = null;
}
}
});
img.addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
if (img.getDrawingMode()) {
if (withinRange(e.getX(), e.getY())) {
int[] toUpdate = img.setOval(e.getX(), e.getY());
oldX = toUpdate[0];
oldY = toUpdate[1];
img.repaint();
}
}
if (img.getTextMode()) {
if (withinRange(e.getX(), e.getY())) {
Point dragPoint = e.getPoint();
h, height);
img.repaint();
}
}
}
});
if (img!=null) {
contentArea.add(img);
}
}
private static boolean withinRange(int x, int y) {
if (x > img.getX() && x < img.getX() + img.getWidth()) {
if (y > img.getY() && y < img.getY() + img.getHeight()) {
return true;
}
}
return false;
}
private static void flipImage() {
if (!img.isFlipped()) {
img.setFlipped(true);
} else if (img.isFlipped()) {
img.setFlipped(false);
}
}
drawLine() is called above in this main class, when a mousedrag occurs. Problem is that the strokes don't appear to show.
I know that the program is calling g2.fillOval() because I am printing out a verification statement afterwards.
Additionally, I have created print statements for when the mouse is pressed and dragged and they are getting the correct coordinates?
Why don't red strokes appear? I'm confused. Is it the way my code is structured?

The crux of your problem is that you are trying to draw something outside the paintComponent method, which is never supported. Whatever you draw will get overwritten by the next call of paintComponent, which will happen almost instantly. We can solve this by storing the co-ordinates of the oval and drawing it within paintComponent instead of trying to draw on a graphics object outside of the paintComponent method. See code below:
First we are going to add the following variables to your PhotoComponent class:
private boolean drawOval = false;
private int ovalX = 0;
private int ovalY = 0;
Then we will add methods for controlling them:
public int[] setOval(int currentX, int currentY) {
drawOval = true;
int[] toReturn = {ovalX, ovalY};
ovalX = currentX;
ovalY = currentY;
return toReturn;
}
public void removeOval() {
drawOval = false;
}
After that we can change the paintComponent method to have it draw the oval based on those variables:
#Override
public void paintComponent(Graphics g) {
//Does all the drawing and contains whatever state information is associated with the photo
//create an action event to auto call repaint
//call repaint anytime flip was changed to true or false
super.paintComponent(g);
g2 = (Graphics2D) g;
int x = (contentAreaWidth - pic.getWidth(null)) / 2;
int y = (contentAreaHeight - pic.getHeight(null)) / 2;
if (!flipped) {
g2.drawImage(pic, x, y, null);
} else if (flipped) {
g2.setColor(Color.WHITE);
g2.fillRect(x, y, pic.getWidth(null), pic.getHeight(null));
g2.drawRect(x, y, pic.getWidth(null), pic.getHeight(null));
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(Color.RED);
}
//took the code you already used for drawing the oval and moved it here
if (drawOval) {
g2.setPaint(Color.RED);
int brushSize = 5;
g2.fillOval((ovalX - (brushSize / 2)), (ovalY - (brushSize / 2)), brushSize, brushSize);
}
}
Finally change the addPhotoComponent method to update those variables instead of trying to draw the oval directly:
private static void addPhotoComponent(File file) {
Image image = null;
try {
image = ImageIO.read(file);
} catch (IOException e2) {
System.out.println("ERROR: Couldn't get image.");
}
img = new PhotoComponent(image, contentArea);
img.revalidate();
img.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
// your code here
System.out.println("You flipped the photo!!!");
flipImage();
img.repaint();
}
}
#Override
public void mousePressed(MouseEvent e) {
img.setOval(e.getX(), e.getY());
}
#Override
public void mouseReleased(MouseEvent e) {
img.removeOval();
}
});
img.addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
int[] toUpdate = img.setOval(e.getX(), e.getY());
oldX = toUpdate[0];
oldY = toUpdate[1];
}
});
if (img != null) {
contentArea.add(img);
}
}

Java: I need help to moove JLabel with keyboards [duplicate]

I'm new to Java graphics and threads, and I'm trying to make a game (specifically, Pong). The idea is that two people can play on the same keyboard (i.e. there are two paddles that are controlled through different keys). Currently, both players can't move their paddle at the same time.
Is there a solution to this? Are separate threads the answer?
If possible, I'd like the paddles to be able to move (at least seemingly) at the same time.
Update: It seems like using a Set<Integer> to store pressed keys is the best option. I've done that (and it works), but I'm wondering if any of this code is not on the Event Dispatching Thread (EDT) and if I need to use SwingUtilities.invokeLater();. Here's the necessary code:
private Set<Integer> keysDown = Collections.synchronizedSet(new HashSet<Integer>());
public void keyPressed(KeyEvent e)
{
keysDown.add(e.getKeyCode());
}
public void keyReleased(KeyEvent e)
{
keysDown.remove(e.getKeyCode());
}
public void updatePaddlePositions()
{
if (keysDown.contains(KeyEvent.VK_W))
paddleOne.move(-PADDLE_MOVE_INCREMENT);
if (keysDown.contains(KeyEvent.VK_S))
paddleOne.move(PADDLE_MOVE_INCREMENT);
if (keysDown.contains(KeyEvent.VK_UP))
paddleTwo.move(-PADDLE_MOVE_INCREMENT);
if (keysDown.contains(KeyEvent.VK_DOWN))
paddleTwo.move(PADDLE_MOVE_INCREMENT);
try {
Thread.sleep(DELAY);
} catch (InterruptedException e) {
System.out.println("You Interrupted the game!");
}
canvas.repaint();
}
Here's the paintComponent method of the canvas object:
public void paintComponent(Graphics g)
{
super.paintComponent(g);
paddleOne.paint(g);
paddleTwo.paint(g);
updatePaddlePositions(); // Does this need to be SwingUtilities.invokeLater(this)?
// And should updatePaddlePositions() be run() as a result?
}
And here's the paint method of the paddleOne and paddleTwo objects:
public void paint(Graphics g)
{
g.setColor(Color.BLACK);
g.fillRect(x, y, PADDLE_WIDTH, PADDLE_HEIGHT);
}
Feel free to comment on my design if anything pops out as "bad" to you. Lastly, what does Collections.synchronizedSet(new HashSet<Integer>()) mean/do?
Update #2: It seems like key bindings are the way to go (even though they take more code, in this case). What make key bindings better? Is it that they work separately from everything else (and don't need window focus like key listeners)?
Also, I understand that HashSet<Integer> is just a subclass of Set<Integer>, but what is the purpose of Collections.synchronizedSet(...)? I'm assuming it has to do with threads, but I don't know why it's needed in this program (if it is at all).

First off, use Swing KeyBindings Also I see no real need for multi-threadung unless you want your game multi-threaded.
To clarify the problem is you need to be able for 2 players to press different keys?
If so:
Solution:
Simply use booleans to flag whether or not a key is pressed down, you would than of course have to reset the flag when the key is released.
In your game logic you would check the states if the booleans and act appropriately.
See my below example (both paddles can move independently using W and S and UP and DOWN keys):
public class GameLogic {
public GameLogic() {
initComponents();
}
private void initComponents() {
JFrame frame = new JFrame("Game Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//create the gamepanel
final GamePanel gp = new GamePanel(600, 500);
//create panel to hold buttons to start pause and stop the game
JPanel buttonPanel = new JPanel();
buttonPanel.setOpaque(false);
final JButton startButton = new JButton("Start");
final JButton pauseButton = new JButton("Pause");
final JButton stopButton = new JButton("Stop");
pauseButton.setEnabled(false);
stopButton.setEnabled(false);
//add listeners to buttons (most of the actions - excuse the pun - takes palce here :)
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
//clear enitites currently in array
gp.clearEntities();
ArrayList<BufferedImage> ballEntityImages = new ArrayList<>();
ArrayList<Long> ballEntityTimings = new ArrayList<>();
ballEntityImages.add(createColouredImage("white", 50, 50, true));
ballEntityTimings.add(500l);
Entity ballEntity = new Entity(gp.getWidth() / 2, gp.getHeight() / 2, ballEntityImages, ballEntityTimings);
ballEntity.RIGHT = true;
//create images for entities
ArrayList<BufferedImage> advEntityImages = new ArrayList<>();
ArrayList<Long> advEntityTimings = new ArrayList<>();
advEntityImages.add(createColouredImage("orange", 10, 100, false));
advEntityTimings.add(500l);
advEntityImages.add(createColouredImage("blue", 10, 100, false));
advEntityTimings.add(500l);
//create entities
AdvancedSpritesEntity player1Entity = new AdvancedSpritesEntity(0, 100, advEntityImages, advEntityTimings);
ArrayList<BufferedImage> entityImages = new ArrayList<>();
ArrayList<Long> entityTimings = new ArrayList<>();
entityImages.add(createColouredImage("red", 10, 100, false));
entityTimings.add(500l);//as its the only image it doesnt really matter what time we put we could use 0l
//entityImages.add(createColouredImage("magenta", 100, 100));
//entityTimings.add(500l);
Entity player2Entity = new Entity(gp.getWidth() - 10, 200, entityImages, entityTimings);
gp.addEntity(player1Entity);
gp.addEntity(player2Entity);//just a standing still Entity for testing
gp.addEntity(ballEntity);//just a standing still Entity for testing
//create Keybingings for gamepanel
GameKeyBindings gameKeyBindings = new GameKeyBindings(gp, player1Entity, player2Entity);
GamePanel.running.set(true);
//start the game loop which will repaint the screen
runGameLoop(gp);
startButton.setEnabled(false);
pauseButton.setEnabled(true);
stopButton.setEnabled(true);
}
});
pauseButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
boolean b = GamePanel.paused.get();
GamePanel.paused.set(!b);//set it to the opposite of what it was i.e paused to unpaused and vice versa
if (pauseButton.getText().equals("Pause")) {
pauseButton.setText("Un-pause");
} else {
pauseButton.setText("Pause");
}
}
});
stopButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
GamePanel.running.set(false);
GamePanel.paused.set(false);
/* if we want enitites to be cleared and a blank panel shown
gp.clearEntities();
gp.repaint();
*/
if (!pauseButton.getText().equals("Pause")) {
pauseButton.setText("Pause");
}
startButton.setEnabled(true);
pauseButton.setEnabled(false);
stopButton.setEnabled(false);
}
});
//add buttons to panel
buttonPanel.add(startButton);
buttonPanel.add(pauseButton);
buttonPanel.add(stopButton);
//add gamepanel to jframe and button panel
frame.add(gp);
frame.add(buttonPanel, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
//Simply used for testing (to simulate sprites) can create different colored images
public static BufferedImage createColouredImage(String color, int w, int h, boolean circular) {
BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = img.createGraphics();
switch (color.toLowerCase()) {
case "green":
g2.setColor(Color.GREEN);
break;
case "magenta":
g2.setColor(Color.MAGENTA);
break;
case "red":
g2.setColor(Color.RED);
break;
case "yellow":
g2.setColor(Color.YELLOW);
break;
case "blue":
g2.setColor(Color.BLUE);
break;
case "orange":
g2.setColor(Color.ORANGE);
break;
case "cyan":
g2.setColor(Color.CYAN);
break;
case "gray":
g2.setColor(Color.GRAY);
break;
default:
g2.setColor(Color.WHITE);
break;
}
if (!circular) {
g2.fillRect(0, 0, img.getWidth(), img.getHeight());
} else {
g2.fillOval(0, 0, img.getWidth(), img.getHeight());
}
g2.dispose();
return img;
}
//Starts a new thread and runs the game loop in it.
private void runGameLoop(final GamePanel gp) {
Thread loop = new Thread(new Runnable() {
#Override
public void run() {
gp.gameLoop();
}
});
loop.start();
}
//Code starts here
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {//attempt to set look and feel to nimbus Java 7 and up
for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
GameLogic gameLogic = new GameLogic();
}
});
}
}
class GameKeyBindings {
public GameKeyBindings(JComponent gp, final Entity entity, final Entity entity2) {
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, false), "W pressed");
gp.getActionMap().put("W pressed", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity.UP = true;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, true), "W released");
gp.getActionMap().put("W released", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity.UP = false;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, false), "S pressed");
gp.getActionMap().put("S pressed", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity.DOWN = true;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, true), "S released");
gp.getActionMap().put("S released", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity.DOWN = false;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "down pressed");
gp.getActionMap().put("down pressed", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity2.DOWN = true;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "down released");
gp.getActionMap().put("down released", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity2.DOWN = false;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "up pressed");
gp.getActionMap().put("up pressed", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity2.UP = true;
}
});
gp.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, true), "up released");
gp.getActionMap().put("up released", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
entity2.UP = false;
}
});
}
}
class AdvancedSpritesEntity extends Entity {
public AdvancedSpritesEntity(int x, int y, ArrayList<BufferedImage> images, ArrayList<Long> timings) {
super(x, y, images, timings);
}
void setAnimation(ArrayList<BufferedImage> images, ArrayList<Long> timings) {
reset();//reset variables of animator class
setFrames(images, timings);//set new frames for animation
}
}
class Entity extends Animator {
private int speed = 5;
public boolean UP = false, DOWN = false, LEFT = false, RIGHT = false, visible;
private Rectangle2D.Double rect;
public Entity(int x, int y, ArrayList<BufferedImage> images, ArrayList<Long> timings) {
super(images, timings);
UP = false;
DOWN = false;
LEFT = false;
RIGHT = false;
visible = true;
rect = new Rectangle2D.Double(x, y, getCurrentImage().getWidth(), getCurrentImage().getHeight());
}
public void setSpeed(int speed) {
this.speed = speed;
}
public int getSpeed() {
return speed;
}
public boolean isVisible() {
return visible;
}
public void setVisible(boolean visible) {
this.visible = visible;
}
public HashSet<String> getMask(Entity e) {
HashSet<String> mask = new HashSet<>();
int pixel, a;
BufferedImage bi = e.getCurrentImage();//gets the current image being shown
for (int i = 0; i < bi.getWidth(); i++) { // for every (x,y) component in the given box,
for (int j = 0; j < bi.getHeight(); j++) {
pixel = bi.getRGB(i, j); // get the RGB value of the pixel
a = (pixel >> 24) & 0xff;
if (a != 0) { // if the alpha is not 0, it must be something other than transparent
mask.add((e.getX() + i) + "," + (e.getY() - j)); // add the absolute x and absolute y coordinates to our set
}
}
}
return mask; //return our set
}
// Returns true if there is a collision between object a and object b
public boolean checkPerPixelCollision(Entity b) {
// This method detects to see if the images overlap at all. If they do, collision is possible
int ax1 = (int) getX();
int ay1 = (int) getY();
int ax2 = ax1 + (int) getWidth();
int ay2 = ay1 + (int) getHeight();
int bx1 = (int) b.getX();
int by1 = (int) b.getY();
int bx2 = bx1 + (int) b.getWidth();
int by2 = by1 + (int) b.getHeight();
if (by2 < ay1 || ay2 < by1 || bx2 < ax1 || ax2 < bx1) {
return false; // Collision is impossible.
} else { // Collision is possible.
// get the masks for both images
HashSet<String> maskPlayer1 = getMask(this);
HashSet<String> maskPlayer2 = getMask(b);
maskPlayer1.retainAll(maskPlayer2); // Check to see if any pixels in maskPlayer2 are the same as those in maskPlayer1
if (maskPlayer1.size() > 0) { // if so, than there exists at least one pixel that is the same in both images, thus
return true;
}
}
return false;
}
public void move() {
if (UP) {
rect.y -= speed;
}
if (DOWN) {
rect.y += speed;
}
if (LEFT) {
rect.x -= speed;
}
if (RIGHT) {
rect.x += speed;
}
}
#Override
public void update(long elapsedTime) {
super.update(elapsedTime);
getWidth();//set the rectangles height accordingly after image update
getHeight();//set rectangles height accordingle after update
}
public boolean intersects(Entity e) {
return rect.intersects(e.rect);
}
public double getX() {
return rect.x;
}
public double getY() {
return rect.y;
}
public double getWidth() {
if (getCurrentImage() == null) {//there might be no image (which is unwanted ofcourse but we must not get NPE so we check for null and return 0
return rect.width = 0;
}
return rect.width = getCurrentImage().getWidth();
}
public double getHeight() {
if (getCurrentImage() == null) {
return rect.height = 0;
}
return rect.height = getCurrentImage().getHeight();
}
}
class Animator {
private ArrayList<BufferedImage> frames;
private ArrayList<Long> timings;
private int currIndex;
private long animationTime;
private long totalAnimationDuration;
private AtomicBoolean done;//used to keep track if a single set of frames/ an animtion has finished its loop
public Animator(ArrayList<BufferedImage> frames, ArrayList< Long> timings) {
currIndex = 0;
animationTime = 0;
totalAnimationDuration = 0;
done = new AtomicBoolean(false);
this.frames = new ArrayList<>();
this.timings = new ArrayList<>();
setFrames(frames, timings);
}
public boolean isDone() {
return done.get();
}
public void reset() {
totalAnimationDuration = 0;
done.getAndSet(false);
}
public void update(long elapsedTime) {
if (frames.size() > 1) {
animationTime += elapsedTime;
if (animationTime >= totalAnimationDuration) {
animationTime = animationTime % totalAnimationDuration;
currIndex = 0;
done.getAndSet(true);
}
while (animationTime > timings.get(currIndex)) {
currIndex++;
}
}
}
public BufferedImage getCurrentImage() {
if (frames.isEmpty()) {
return null;
} else {
try {
return frames.get(currIndex);
} catch (Exception ex) {//images might have been altered so we reset the index and return first image of the new frames/animation
currIndex = 0;
return frames.get(currIndex);
}
}
}
public void setFrames(ArrayList<BufferedImage> frames, ArrayList< Long> timings) {
if (frames == null || timings == null) {//so that constructor super(null,null) cause this to throw NullPointerException
return;
}
this.frames = frames;
this.timings.clear();
for (long animTime : timings) {
totalAnimationDuration += animTime;
this.timings.add(totalAnimationDuration);
}
}
}
class GamePanel extends JPanel {
private final static RenderingHints textRenderHints = new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
private final static RenderingHints imageRenderHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
private final static RenderingHints colorRenderHints = new RenderingHints(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
private final static RenderingHints interpolationRenderHints = new RenderingHints(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
private final static RenderingHints renderHints = new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
public static AtomicBoolean running = new AtomicBoolean(false), paused = new AtomicBoolean(false);
private int width, height, frameCount = 0, fps = 0;
private ArrayList<Entity> entities = new ArrayList<>();
private final Random random = new Random();
public GamePanel(int w, int h) {
super(true);//make sure double buffering is enabled
setIgnoreRepaint(true);//mustnt repaint itself the gameloop will do that
width = w;
height = h;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(width, height);
}
public void addEntity(Entity e) {
entities.add(e);
}
void clearEntities() {
entities.clear();
}
//Only run this in another Thread!
public void gameLoop() {
//This value would probably be stored elsewhere.
final double GAME_HERTZ = 30.0;
//Calculate how many ns each frame should take for our target game hertz.
final double TIME_BETWEEN_UPDATES = 1000000000 / GAME_HERTZ;
//At the very most we will update the game this many times before a new render.
//If you're worried about visual hitches more than perfect timing, set this to 1.
final int MAX_UPDATES_BEFORE_RENDER = 5;
//We will need the last update time.
double lastUpdateTime = System.nanoTime();
//Store the last time we rendered.
double lastRenderTime = System.nanoTime();
//If we are able to get as high as this FPS, don't render again.
final double TARGET_FPS = 60;
final double TARGET_TIME_BETWEEN_RENDERS = 1000000000 / TARGET_FPS;
//Simple way of finding FPS.
int lastSecondTime = (int) (lastUpdateTime / 1000000000);
//store the time we started this will be used for updating map and charcter animations
long currTime = System.currentTimeMillis();
while (running.get()) {
if (!paused.get()) {
double now = System.nanoTime();
long elapsedTime = System.currentTimeMillis() - currTime;
currTime += elapsedTime;
int updateCount = 0;
//Do as many game updates as we need to, potentially playing catchup.
while (now - lastUpdateTime > TIME_BETWEEN_UPDATES && updateCount < MAX_UPDATES_BEFORE_RENDER) {
updateGame(elapsedTime);//Update the entity movements and collision checks etc (all has to do with updating the games status i.e call move() on Enitites)
lastUpdateTime += TIME_BETWEEN_UPDATES;
updateCount++;
}
//If for some reason an update takes forever, we don't want to do an insane number of catchups.
//If you were doing some sort of game that needed to keep EXACT time, you would get rid of this.
if (now - lastUpdateTime > TIME_BETWEEN_UPDATES) {
lastUpdateTime = now - TIME_BETWEEN_UPDATES;
}
drawGame();//draw the game by invokeing repaint (which will call paintComponent) on this JPanel
lastRenderTime = now;
//Update the frames we got.
int thisSecond = (int) (lastUpdateTime / 1000000000);
if (thisSecond > lastSecondTime) {
//System.out.println("NEW SECOND " + thisSecond + " " + frameCount);
fps = frameCount;
frameCount = 0;
lastSecondTime = thisSecond;
}
//Yield until it has been at least the target time between renders. This saves the CPU from hogging.
while (now - lastRenderTime < TARGET_TIME_BETWEEN_RENDERS && now - lastUpdateTime < TIME_BETWEEN_UPDATES) {
//allow the threading system to play threads that are waiting to run.
Thread.yield();
//This stops the app from consuming all your CPU. It makes this slightly less accurate, but is worth it.
//You can remove this line and it will still work (better), your CPU just climbs on certain OSes.
//FYI on some OS's this can cause pretty bad stuttering. Scroll down and have a look at different peoples' solutions to this.
//On my OS(Windows 7 x64 intel i3) it does not allow for time to make enityt etc move thus all stands still
try {
Thread.sleep(1);
} catch (Exception e) {
}
now = System.nanoTime();
}
}
}
fps = 0;//no more running set fps to 0
}
private void drawGame() {
//Both revalidate and repaint are thread-safe — you need not invoke them from the event-dispatching thread. http://docs.oracle.com/javase/tutorial/uiswing/layout/howLayoutWorks.html
repaint();
}
private void updateGame(long elapsedTime) {
updateEntityMovements(elapsedTime);
checkForCollisions();
}
private void checkForCollisions() {
if (entities.get(0).intersects(entities.get(2)) || entities.get(1).intersects(entities.get(2))) {
if (entities.get(2).LEFT) {
entities.get(2).RIGHT = true;
entities.get(2).LEFT = false;
} else {
entities.get(2).LEFT = true;
entities.get(2).RIGHT = false;
}
System.out.println("Intersecting");
} /*
//This is best used when images have transparent and non-transparent pixels (only detects pixel collisions of non-transparent pixels)
if (entities.get(0).checkPerPixelCollision(entities.get(2)) | entities.get(1).checkPerPixelCollision(entities.get(2))) {
if (entities.get(2).LEFT) {
entities.get(2).RIGHT = true;
entities.get(2).LEFT = false;
} else {
entities.get(2).LEFT = true;
entities.get(2).RIGHT = false;
}
System.out.println("Intersecting");
}
*/
}
private void updateEntityMovements(long elapsedTime) {
for (Entity e : entities) {
e.update(elapsedTime);
e.move();
}
}
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
Graphics2D g2d = (Graphics2D) grphcs;
applyRenderHints(g2d);
drawBackground(g2d);
drawEntitiesToScreen(g2d);
drawFpsCounter(g2d);
frameCount++;
}
public static void applyRenderHints(Graphics2D g2d) {
g2d.setRenderingHints(textRenderHints);
g2d.setRenderingHints(imageRenderHints);
g2d.setRenderingHints(colorRenderHints);
g2d.setRenderingHints(interpolationRenderHints);
g2d.setRenderingHints(renderHints);
}
private void drawEntitiesToScreen(Graphics2D g2d) {
for (Entity e : entities) {
if (e.isVisible()) {
g2d.drawImage(e.getCurrentImage(), (int) e.getX(), (int) e.getY(), null);
}
}
}
private void drawFpsCounter(Graphics2D g2d) {
g2d.setColor(Color.WHITE);
g2d.drawString("FPS: " + fps, 5, 10);
}
private void drawBackground(Graphics2D g2d) {
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
//thanks to trashgod for lovely testing background :) http://stackoverflow.com/questions/3256269/jtextfields-on-top-of-active-drawing-on-jpanel-threading-problems/3256941#3256941
g2d.setColor(Color.BLACK);
for (int i = 0; i < 128; i++) {
g2d.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));//random color
g2d.drawLine(getWidth() / 2, getHeight() / 2, random.nextInt(getWidth()), random.nextInt(getHeight()));
}
}
}

This may be a legitimate use case for the low-level access afforded to a KeyListener. See How to Write a Key Listener and KeyEventDemo; don't forget to requestFocusInWindow(). Also consider offering keyboard control for one player and mouse control for the other.
Addendum: #David Kroukamp has adduced an appealing counter-example using key bindings. For reference, the example cited here illustrates one approach to managing key preferences.

Ball is not moving like I want

i want to create a Pong game. I want to move the ball in a way until it touch a wall. if it touch the wall, it go the other way. The problem is that when I start playing, the ball goes in the right way but when it touch the wall, the ball direction reverse but only for one pixel so the ball reverse for 1 pixel and then the direction change angain and it touch the wall again. My code for the moving ball is in the initBall method. Please help me :(
here is my playPanel class :
private int posX = SCREEN_WIDTH / 2;
private int posY;
public Point posMouse = new Point();
private Point posBall = new Point();
private int playPanelWidth;
private int playPanelHeight;
private int padPanelWidth;
private int padPanelHeight;
private int panPanelWidth;
private int panPanelHeight;
private JLabel player1Score = new JLabel("0");
private JLabel ComputerScore = new JLabel("0");
private JPanel panPlayer1;
public JPanel panComputer;
public JPanel padPlayer1;
public JPanel padComputer;
private JButton but_Escape = new JButton("Press escape to continue !");
/*
* Constructor
*/
// ==============================================
public PlayPanel() {
super(new BorderLayout());
setBackground(PANPLAY_COLOR);
panPlayer1 = new JPanel();
panComputer = new JPanel();
padPlayer1 = new JPanel();
padComputer = new JPanel();
padPlayer1.setBackground(Color.DARK_GRAY);
padComputer.setBackground(Color.DARK_GRAY);
padPlayer1.setPreferredSize(PADPANEL_SIZE);
padComputer.setPreferredSize(PADPANEL_SIZE);
panPlayer1.setBackground(PANPLAY_COLOR);
panComputer.setBackground(PANPLAY_COLOR);
panPlayer1.add(padPlayer1);
panComputer.add(padComputer);
add(panPlayer1, BorderLayout.WEST);
add(panComputer, BorderLayout.EAST);
addMouseMotionListener(this);
panPlayer1.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent arg0) {
setPanPanelWidth(arg0.getComponent().getSize().width);
setPanPanelHeight(arg0.getComponent().getSize().height);
}
});
addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent arg0) {
setPlayPanelWidth(arg0.getComponent().getSize().width);
setPlayPanelHeight(arg0.getComponent().getSize().height);
}
});
}
/*
* Setters and Getters
*/
// ==============================================
public int getPosX() {
return posX;
}
public void setPosX(int posX) {
this.posX = posX;
}
public int getPosY() {
return posY;
}
public void setPosY(int posY) {
this.posY = posY;
}
public JPanel getPanPlayer1() {
return panPlayer1;
}
public void setPanPlayer1(JPanel panPlayer1) {
this.panPlayer1 = panPlayer1;
}
public JPanel getPanComputer() {
return panComputer;
}
public void setPanComputer(JPanel panComputer) {
this.panComputer = panComputer;
}
public int getPlayPanelHeight() {
return playPanelHeight;
}
public void setPlayPanelHeight(int playPanelHeight) {
this.playPanelHeight = playPanelHeight;
}
public int getPlayPanelWidth() {
return playPanelWidth;
}
public void setPlayPanelWidth(int playPanelWidth) {
this.playPanelWidth = playPanelWidth;
}
public int getPadPanelWidth() {
return padPanelWidth;
}
public void setPadPanelWidth(int padPanelWidth) {
this.padPanelWidth = padPanelWidth;
}
public int getPadPanelHeight() {
return padPanelHeight;
}
public void setPadPanelHeight(int padPanelHeight) {
this.padPanelHeight = padPanelHeight;
}
public int getPanPanelWidth() {
return panPanelWidth;
}
public void setPanPanelWidth(int panPanelWidth) {
this.panPanelWidth = panPanelWidth;
}
public int getPanPanelHeight() {
return panPanelHeight;
}
public void setPanPanelHeight(int panPanelHeight) {
this.panPanelHeight = panPanelHeight;
}
/*
* Add the ball
*/
// ==============================================
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setColor(Color.BLACK);
initBall(g2);
// trait épais
g2.setColor(Color.DARK_GRAY);
g2.setStroke(new BasicStroke(10));
g2.drawLine((getPlayPanelWidth() / 2) - 5, getPlayPanelHeight(),
(getPlayPanelWidth() / 2) - 5, 0);
}
/*
* Init ball
*/
// ==============================================
private void initBall(Graphics2D graphics2d) {
int x = getPosX(), y = getPosY();
boolean backX = false;
boolean backY = false;
Graphics2D g2 = graphics2d;
g2.fillOval(posX, posY, BALL_WIDTH, BALL_HEIGHT);
//posBall.setLocation(posX + BALL_WIDTH, posY + (BALL_HEIGHT / 2));
if (x < 1)
backX = false;
if (x > getWidth() - 50)
backX = true;
if (y < 1)
backY = false;
if (y > getHeight() - 50)
backY = true;
if (!backX)
setPosX(++x);
else {
setPosX(--x);
}
if (!backY)
setPosY(++y);
else
setPosY(--y);
repaint();
try {
Thread.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
#Override
public void mouseDragged(MouseEvent arg0) {
}
#Override
public void mouseMoved(MouseEvent arg0) {
posMouse.setLocation(arg0.getX(), arg0.getY()
- (getPadPanelHeight() / 2));
padPlayer1.setLocation(getPanPanelWidth() - 15, (int) posMouse.getY());
padComputer.setLocation(5, (int) posMouse.getY());
}
}

So you have:
private void initBall(Graphics2D graphics2d) {
int x = getPosX(), y = getPosY();
boolean backX = false;
boolean backY = false;
in the beginning, so that regardless of which direction the ball is going, booth booleans are set to false every time. Then, you don't have an "Else" when it comes to setting the back option in
if (x < 1)
backX = false;
if (x > getWidth() - 50)
backX = true;
if (y < 1)
backY = false;
if (y > getHeight() - 50)
backY = true;
What is happening is that the ball is moving in the right direction, until it hits a wall (I'm guessing the top wall). then this is called:
if (y > getHeight() - 50)
backY = true;
So then for that iteration the ball goes back because of
if (!backY)
setPosY(++y);
else
setPosY(--y);
But then you set it back to false right away. I suggest you have
private boolean backX = false; //same for backY
outside your method.

Problems with InfiniteProgressDemo

I have implemented a small example using InfiniteProgressDemo and works perfectly, showing the "loading wheel" rotating at the center of the frame.
Now I have ported it to my program. I have a button for a connect action (do not worry about the BussinessException):
public class ConnectAction extends AbstractAction {
private JFrame framePrincipal;
private InfiniteProgressPanel glassPane;
/**
* Constructor
* #param m
* #param pNodos
* #param pGraficas
* #param front
* #throws BusinessException
*/
public ConnectAction(Main main, DockFrontend front) throws BusinessException{
super();
this.framePrincipal = main.getFramePrincipal();
this.glassPane = new InfiniteProgressPanel();
framePrincipal.setGlassPane(glassPane);
}
private void perform() throws BusinessException {
// DOING SOME HEAVY STUFF...
System.out.println("You've successfully waited :)");
glassPane.stop();
}
#Override
public Object execute() throws BusinessException {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
glassPane.start();
Thread performer = new Thread(new Runnable() {
public void run() {
try {
perform();
} catch (BusinessException e) {
e.printStackTrace();
}
}
}, "Performer");
performer.start();
}
});
return null;
}
#Override
public void redo() throws BusinessException {
// TODO Auto-generated method stub
}
#Override
public void undo() throws BusinessException {
// TODO Auto-generated method stub
}
#Override
protected void initServices() throws BusinessException {
}
}
The only file I needed from the InfiniteProgressDemo demo was InfiniteProgressPane.
When I execute and push my button, the "loading wheel" appears, but not at the center of the frame. It appears on one corner... next second it appears on another corner, and so on. I don't know what's wrong.
I also attach here the InfiniteProgressDemo:
public class InfiniteProgressPanel extends JComponent implements MouseListener
{
protected Area[] ticker = null;
protected Thread animation = null;
protected boolean started = false;
protected int alphaLevel = 0;
protected int rampDelay = 300;
protected float shield = 0.70f;
protected String text = "";
protected int barsCount = 14;
protected float fps = 15.0f;
protected RenderingHints hints = null;
public InfiniteProgressPanel()
{
this("");
}
public InfiniteProgressPanel(String text)
{
this(text, 14);
}
public InfiniteProgressPanel(String text, int barsCount)
{
this(text, barsCount, 0.70f);
}
public InfiniteProgressPanel(String text, int barsCount, float shield)
{
this(text, barsCount, shield, 15.0f);
}
public InfiniteProgressPanel(String text, int barsCount, float shield, float fps)
{
this(text, barsCount, shield, fps, 300);
}
public InfiniteProgressPanel(String text, int barsCount, float shield, float fps, int rampDelay)
{
this.text = text;
this.rampDelay = rampDelay >= 0 ? rampDelay : 0;
this.shield = shield >= 0.0f ? shield : 0.0f;
this.fps = fps > 0.0f ? fps : 15.0f;
this.barsCount = barsCount > 0 ? barsCount : 14;
this.hints = new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
this.hints.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
this.hints.put(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
}
public void setText(String text)
{
repaint();
this.text = text;
}
public String getText()
{
return text;
}
public void start()
{
addMouseListener(this);
setVisible(true);
ticker = buildTicker();
animation = new Thread(new Animator(true));
animation.start();
}
public void stop()
{
if (animation != null) {
animation.interrupt();
animation = null;
animation = new Thread(new Animator(false));
animation.start();
}
}
public void interrupt()
{
if (animation != null) {
animation.interrupt();
animation = null;
removeMouseListener(this);
setVisible(false);
}
}
public void paintComponent(Graphics g)
{
if (started)
{
int width = getWidth();
int height = getHeight();
double maxY = 0.0;
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHints(hints);
g2.setColor(new Color(255, 255, 255, (int) (alphaLevel * shield)));
g2.fillRect(0, 0, getWidth(), getHeight());
for (int i = 0; i < ticker.length; i++)
{
int channel = 224 - 128 / (i + 1);
g2.setColor(new Color(channel, channel, channel, alphaLevel));
g2.fill(ticker[i]);
Rectangle2D bounds = ticker[i].getBounds2D();
if (bounds.getMaxY() > maxY)
maxY = bounds.getMaxY();
}
if (text != null && text.length() > 0)
{
FontRenderContext context = g2.getFontRenderContext();
TextLayout layout = new TextLayout(text, getFont(), context);
Rectangle2D bounds = layout.getBounds();
g2.setColor(getForeground());
layout.draw(g2, (float) (width - bounds.getWidth()) / 2,
(float) (maxY + layout.getLeading() + 2 * layout.getAscent()));
}
}
}
private Area[] buildTicker()
{
Area[] ticker = new Area[barsCount];
Point2D.Double center = new Point2D.Double((double) getWidth() / 2, (double) getHeight() / 2);
double fixedAngle = 2.0 * Math.PI / ((double) barsCount);
for (double i = 0.0; i < (double) barsCount; i++)
{
Area primitive = buildPrimitive();
AffineTransform toCenter = AffineTransform.getTranslateInstance(center.getX(), center.getY());
AffineTransform toBorder = AffineTransform.getTranslateInstance(45.0, -6.0);
AffineTransform toCircle = AffineTransform.getRotateInstance(-i * fixedAngle, center.getX(), center.getY());
AffineTransform toWheel = new AffineTransform();
toWheel.concatenate(toCenter);
toWheel.concatenate(toBorder);
primitive.transform(toWheel);
primitive.transform(toCircle);
ticker[(int) i] = primitive;
}
return ticker;
}
private Area buildPrimitive()
{
Rectangle2D.Double body = new Rectangle2D.Double(6, 0, 30, 12);
Ellipse2D.Double head = new Ellipse2D.Double(0, 0, 12, 12);
Ellipse2D.Double tail = new Ellipse2D.Double(30, 0, 12, 12);
Area tick = new Area(body);
tick.add(new Area(head));
tick.add(new Area(tail));
return tick;
}
protected class Animator implements Runnable
{
private boolean rampUp = true;
protected Animator(boolean rampUp)
{
this.rampUp = rampUp;
}
public void run()
{
Point2D.Double center = new Point2D.Double((double) getWidth() / 2, (double) getHeight() / 2);
double fixedIncrement = 2.0 * Math.PI / ((double) barsCount);
AffineTransform toCircle = AffineTransform.getRotateInstance(fixedIncrement, center.getX(), center.getY());
long start = System.currentTimeMillis();
if (rampDelay == 0)
alphaLevel = rampUp ? 255 : 0;
started = true;
boolean inRamp = rampUp;
while (!Thread.interrupted())
{
if (!inRamp)
{
for (int i = 0; i < ticker.length; i++)
ticker[i].transform(toCircle);
}
repaint();
if (rampUp)
{
if (alphaLevel < 255)
{
alphaLevel = (int) (255 * (System.currentTimeMillis() - start) / rampDelay);
if (alphaLevel >= 255)
{
alphaLevel = 255;
inRamp = false;
}
}
} else if (alphaLevel > 0) {
alphaLevel = (int) (255 - (255 * (System.currentTimeMillis() - start) / rampDelay));
if (alphaLevel <= 0)
{
alphaLevel = 0;
break;
}
}
try
{
Thread.sleep(inRamp ? 10 : (int) (1000 / fps));
} catch (InterruptedException ie) {
break;
}
Thread.yield();
}
if (!rampUp)
{
started = false;
repaint();
setVisible(false);
removeMouseListener(InfiniteProgressPanel.this);
}
}
}
public void mouseClicked(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
}

Finally the problem is that getWidth() and getHeight() methods aren't getting the correct dimensions of the JFrame of my main windows, because they are called straigth forwards. Modifying the InfiniteProgressDemo constructors to receive a JFrame myFrame, and calling myFrame.getWidth() and myFrame.getHeight() got the animation working correctly in the center of the screen.