This is a really simple example I put together…
It basically has a sprite which has a random motion and rotation. The program is capable of rendering between 1 and 10, 000 zombies…seriously…
I’ve used you “main loop” as well, just to be sure…
There’s no real optimisation, if I was really doing this, I would have a pool somewhere with zombies that could pulled from and put to in order to reduce the amount of time it takes to create them…
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ZombieLand {
protected static final Random RND = new Random();
private static BufferedImage zombie;
public static void main(String[] args) {
new ZombieLand();
}
public ZombieLand() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
try {
zombie = ImageIO.read(getClass().getResource("/Zombie.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
final ZombiePane zombiePane = new ZombiePane();
final JSlider slider = new JSlider(1, 10000);
slider.setMajorTickSpacing(1000);
slider.setMinorTickSpacing(100);
slider.setPaintTicks(true);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSlider slider = (JSlider) e.getSource();
zombiePane.setZombies(slider.getValue());
}
});
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(zombiePane);
frame.add(slider, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
slider.setValue(10000);
}
});
}
});
}
public static class ZombiePane extends JPanel {
private List<ZombieSprite> sprites;
protected static final Object SPRITE_LOCK = new Object();
private int desiredCount = 1;
public ZombiePane() {
sprites = new ArrayList<>(25);
sprites.add(new ZombieSprite());
Thread t = new Thread(new MainLoop());
t.setDaemon(false);
t.start();
Font font = getFont();
setFont(font.deriveFont(Font.BOLD, 48f));
}
public void setZombies(int count) {
desiredCount = count;
}
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
synchronized (SPRITE_LOCK) {
for (ZombieSprite sprite : sprites) {
sprite.paint(g2d);
}
}
String text = Integer.toString(sprites.size());
FontMetrics fm = g2d.getFontMetrics();
g2d.drawString(text, getWidth() - fm.stringWidth(text), getHeight() - fm.getHeight() + fm.getAscent());
g2d.dispose();
}
protected void cycle() {
synchronized (SPRITE_LOCK) {
if (desiredCount != sprites.size()) {
int count = 0;
int fill = 100;
while (sprites.size() > desiredCount && count < fill) {
sprites.remove(0);
count++;
}
count = 0;
while (sprites.size() < desiredCount && count < fill) {
sprites.add(new ZombieSprite());
count++;
}
}
for (ZombieSprite sprite : sprites) {
sprite.update(getWidth(), getHeight());
}
}
}
public class MainLoop implements Runnable {
private int DELAY = 40;
public void run() {
long beforeTime, timeDiff, sleep;
beforeTime = System.currentTimeMillis();
while (true) {
cycle();
repaint();
timeDiff = System.currentTimeMillis() - beforeTime;
sleep = DELAY - timeDiff;
if (sleep < 0) {
sleep = 2;
}
try {
Thread.sleep(sleep);
} catch (InterruptedException e) {
System.out.println("interrupted");
}
beforeTime = System.currentTimeMillis();
}
}
}
}
public static class ZombieSprite {
// private BufferedImage zombie;
private Point motionDelta;
private double rotationDelta;
private Point location;
private double angle;
public ZombieSprite() {
motionDelta = new Point();
motionDelta.x = (int) ((Math.random() * 3) + 1);
motionDelta.y = (int) ((Math.random() * 3) + 1);
if (Math.random() > 0.5) {
motionDelta.x *= -1;
}
if (Math.random() > 0.5) {
motionDelta.y *= -1;
}
rotationDelta = (int) ((Math.random() * 9) + 1);
if (Math.random() > 0.5) {
rotationDelta *= -1;
}
}
public void paint(Graphics2D g2d) {
if (location != null) {
Graphics2D g = (Graphics2D) g2d.create();
AffineTransform at = new AffineTransform();
at.translate(location.x, location.y);
at.rotate(Math.toRadians(angle), zombie.getWidth() / 2, zombie.getHeight() / 2);
g.setTransform(at);
g.drawImage(zombie, 0, 0, null);
g.dispose();
}
}
public void update(int width, int height) {
if (location == null) {
angle = (Math.random() * 360d);
location = new Point();
location.x = (int) (Math.random() * (width - zombie.getWidth()));
location.y = (int) (Math.random() * (height - zombie.getHeight()));
} else {
angle += rotationDelta;
location.x += motionDelta.x;
location.y += motionDelta.y;
if (location.x < 0) {
location.x = 0;
motionDelta.x *= -1;
} else if (location.x + zombie.getWidth() > width) {
location.x = width - zombie.getWidth();
motionDelta.x *= -1;
}
if (location.y < 0) {
location.y = 0;
motionDelta.y *= -1;
} else if (location.y + zombie.getHeight() > height) {
location.y = height - zombie.getHeight();
motionDelta.y *= -1;
}
}
}
}
}