- I'd encourage the use of a
javax.swing.Timer
to control the frame rate, rather than an uncontrolled loop
- Once the timer "ticks", you need to increment the current frame, get the current image to be rendered and call
repaint
on the JPanel
- Use
Graphics#drawImage
to render the image.
See...
for more details
There is a cascading series of issues with your Spritesheet
class, apart from the fact that it won't actually compile, there are issues with you returning the wrong values from some methods and relying on values which are better calculated...
I had to modify your code so much, I can't remember most of them
public int getHeight() {
return frameWidth;
}
and
public BufferedImage[] getAllSprites() {
BufferedImage[] sprites = new BufferedImage[frames];
int y = 0;
for (int i = 0; i < frames; i++) {
x = i * frameWidth;
currentSprite = sheet.getSprite(x,y,frameHeight,frameWidth);
sprites.add(currentSprite);
}
return sprites;
}
Stand out as two main examples...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestSpriteSheet {
public static void main(String[] args) {
new TestSpriteSheet();
}
public TestSpriteSheet() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Spritesheet spritesheet;
private BufferedImage currentFrame;
private int frame;
public TestPane() {
spritesheet = new Spritesheet("/Sheet02.gif", 240, 220);
Timer timer = new Timer(100, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
currentFrame = spritesheet.getSprite(frame % spritesheet.getFrameCount());
repaint();
frame++;
}
});
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(240, 220);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (currentFrame != null) {
Graphics2D g2d = (Graphics2D) g.create();
int x = (getWidth() - currentFrame.getWidth()) / 2;
int y = (getHeight() - currentFrame.getHeight()) / 2;
g2d.drawImage(currentFrame, x, y, this);
g2d.dispose();
}
}
}
public class Spritesheet {
//Instance Variables
private String path;
private int frameWidth;
private int frameHeight;
private BufferedImage sheet = null;
private BufferedImage[] frameImages;
//Constructors
public Spritesheet(String aPath, int width, int height) {
path = aPath;
frameWidth = width;
frameHeight = height;
try {
sheet = ImageIO.read(getClass().getResourceAsStream(path));
frameImages = getAllSprites();
} catch (IOException e) {
e.printStackTrace();
}
}
public BufferedImage getSprite(int frame) {
return frameImages[frame];
}
//Methods
public int getHeight() {
return frameHeight;
}
public int getWidth() {
return frameWidth;
}
public int getColumnCount() {
return sheet.getWidth() / getWidth();
}
public int getRowCount() {
return sheet.getHeight() / getHeight();
}
public int getFrameCount() {
int cols = getColumnCount();
int rows = getRowCount();
return cols * rows;
}
private BufferedImage getSprite(int x, int y, int h, int w) {
BufferedImage sprite = sheet.getSubimage(x, y, h, w);
return sprite;
}
public BufferedImage[] getAllSprites() {
int cols = getColumnCount();
int rows = getRowCount();
int frameCount = getFrameCount();
BufferedImage[] sprites = new BufferedImage[frameCount];
int index = 0;
System.out.println("cols = " + cols);
System.out.println("rows = " + rows);
System.out.println("frameCount = " + frameCount);
for (int row = 0; row < getRowCount(); row++) {
for (int col = 0; col < getColumnCount(); col++) {
int x = col * getWidth();
int y = row * getHeight();
System.out.println(index + " " + x + "x" + y);
BufferedImage currentSprite = getSprite(x, y, getWidth(), getHeight());
sprites[index] = currentSprite;
index++;
}
}
return sprites;
}
}
}
Remember, animation is the illusion of change over time. You need to provide a delay between each frame of the animation, long enough for the user to recognise it, but short enough to make the animation look smooth.
In the above example, I've used 100
milliseconds, simply as an arbitrary value. It could be possible to use something more like 1000 / spritesheet.getFrameCount()
, which will allow a full second for the entire animation (all the frames within one second).
You might need to use different values, for longer or short animations, depending on your needs