Porlus
JGO n00b  Posts: 22
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on:
2012-02-07 11:57:54 » |
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Hello, I've got a problem with a spritesheet I'm trying to make using Java 2D. I first load an external PNG into a BufferedImage using the ImageIO class and using a Sprite class I pass in the buffered spritesheet, where I want it in the frame (x, y), the top left hand point of the tile from the spritesheet that I want to extract (xOffset, yOffset) and the width and height of the tile. The external PNG is just a spritesheet containing the characters a-z, 0-9 that I made in photoshop, with each tile being 20x20 pixels. I'll post the code so you can see exactly what I mean, but what the problem is, is that when a new character is drawn using the Component classes paint method, the previously rendered characters disappear. 1
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| import java.awt.BorderLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
public class Main
{
public static final int WIDTH = 300;
public static final int HEIGHT = 300;
private Screen screen;
public Main()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.setSize(WIDTH, HEIGHT);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
BufferedImage ss = null;
try
{
ss = ImageIO.read(new File("charSprite.png"));
}
catch(IOException e)
{
e.printStackTrace();
}
screen = new Screen(WIDTH, HEIGHT);
screen.loadImage(new Sprite(ss, 0, 0, 20, 20).getSprite(), 20, 20);
screen.loadImage(new Sprite(ss, 0, 0, 20, 20).getSprite(), 40, 40);
frame.add(screen);
}
public static void main(String[] args)
{
new Main();
}
} |
Here's the Sprite class, for dissecting the tile from the spritesheet: 1
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| import java.awt.image.BufferedImage;
public class Sprite
{
private BufferedImage sprite;
public Sprite(BufferedImage ss, int xOffset, int yOffset, int width, int height)
{
sprite = ss.getSubimage(xOffset, yOffset, width, height);
}
public BufferedImage getSprite()
{
return sprite;
}
} |
Here's the screen class which holds the bufferedimage containing each element within the screen: 1
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| import java.awt.Component;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
public class Screen extends Component
{
private BufferedImage display = null;
private int[] pixels;
public Screen(int w, int h)
{
display = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
pixels = new int[w * h];
}
public void loadImage(BufferedImage im, int x, int y)
{
int[] p = im.getRGB(0, 0, im.getWidth(), im.getHeight(), null, 0, im.getWidth());
for(int y1 = 0; y1 < im.getHeight(); y1++)
{
for(int x1 = 0; x1 < im.getWidth(); x1++)
{
pixels[(y1 + y) * display.getWidth() + (x1 + x)] = p[y1 * im.getWidth() + x1];
}
}
display.setRGB(0, 0, display.getWidth(), display.getHeight(), pixels, 0, display.getWidth());
repaint();
}
public void paint(Graphics g)
{
g.drawImage(display, 0, 0, display.getWidth(), display.getHeight(), null);
}
} |
I'm quite new to this and just trying to understand how swing works so any help would be appreciated. Thanks! Paul |
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ra4king
JGO Kernel Posts: 3160 Medals: 196
I'm the King!
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«
Reply #1 on:
2012-02-07 19:14:17 » |
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JFrame's ContentPane's default layout is BorderLayout, which uses 1 component for the center, and 1 component for each of the 4 sides. Calling JFrame.add(Component) adds it to the center component. Any further calls will replace the previous one. What you need is 1 component that you draw everything to.
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Porlus
JGO n00b Posts: 22
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Reply #2 on:
2012-02-07 19:53:26 » |
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Thanks for the reply. Yeah, I've just thought to add a screen class to keep a pixels by pixels reference of everything on the screen, then I can just pass in bufferedimages, extract their pixel arrays and then overlay the new image within a nested loop in the correct position.
I've updated my original post now to what I currently have and it seems to work perfectly, except the images only seem to appear roughly 50% of the time once the program is ran. If I minimize the program and maximize it again the images appear, though. Any idea what could be causing that?
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Games published by our own members! Go get 'em! 
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GabrielBailey74
Full Member Posts: 157 Medals: 2
Owner of Elite Demons R.I.P
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Reply #3 on:
2012-02-07 19:56:24 » |
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Could be because you're only adding the Screen there once, you'd need to add a loop of somekind, than handle your paint method in there so it's constantly repainting.
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Porlus
JGO n00b Posts: 22
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Reply #4 on:
2012-02-07 20:05:25 » |
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I think it stays as it is until you clear the pixel array and update the screen buffer. I'll have to create a clear buffer method or something to clear that out. I think the problem lies around here in the main class: 1
| ss = ImageIO.read(new File("charSprite.png")); |
As when the pictures don't render, they both don't and likewise when they do. So that would suggest that it was a problem with the spritesheet I'm feeding into the sprite classes. Not really sure about a solution though. |
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GabrielBailey74
Full Member Posts: 157 Medals: 2
Owner of Elite Demons R.I.P
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«
Reply #5 on:
2012-02-07 20:08:12 » |
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What I would do, and what I do do is: Take the spritesheet, chop it down into proper frames, give it a pinkish background color (if you want it to be transparent), load it through transparency and ignore those pink pixels. Thought i've never tried grabbing a subImage of a image.. You could make your Screen class extend a JPanel, than add the JPanel to the frame, make your Main class "extends Screen". You could do your Screen class like this: 1
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| import java.awt.Component;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
public class Screen extends JPanel {
private BufferedImage display = null;
private int[] pixels;
public Screen(int w, int h)
{
display = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
pixels = new int[w * h];
}
public void loadImage(BufferedImage im, int x, int y)
{
int[] p = im.getRGB(0, 0, im.getWidth(), im.getHeight(), null, 0, im.getWidth());
for(int y1 = 0; y1 < im.getHeight(); y1++)
{
for(int x1 = 0; x1 < im.getWidth(); x1++)
{
pixels[(y1 + y) * display.getWidth() + (x1 + x)] = p[y1 * im.getWidth() + x1];
}
}
display.setRGB(0, 0, display.getWidth(), display.getHeight(), pixels, 0, display.getWidth());
repaint();
}
public void cycle() { repaint();
}
public void paint(Graphics g) {
super.paint(g);
final Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.drawImage(display, 0, 0, display.getWidth(), display.getHeight(), null);
}
} |
And your Main class like this: 1
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| import java.awt.BorderLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
public class Main extends Screen implements Runnable { public static final int WIDTH = 300;
public static final int HEIGHT = 300;
private Screen screen;
public Main() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.setSize(WIDTH, HEIGHT);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
BufferedImage ss = null;
try {
ss = ImageIO.read(new File("charSprite.png"));
} catch(IOException e) {
e.printStackTrace();
}
screen = new Screen(WIDTH, HEIGHT);
screen.loadImage(new Sprite(ss, 0, 0, 20, 20).getSprite(), 20, 20);
screen.loadImage(new Sprite(ss, 0, 0, 20, 20).getSprite(), 40, 40);
frame.add(new Screen());
frame.setVisible(true); }
public static void main(String[] args) {
new Main();
}
@Override
public void run() { super.cycle();
}
} |
So your Main class is automaticly calling that "cycle" method from your Screen class which is than telling it to "repaint", which was changed to "super.paint(g)", which would paint your GUI/Main screen. Hope it helps some mate (Would need proper imports/changes made). |
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Porlus
JGO n00b Posts: 22
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Reply #6 on:
2012-02-07 20:36:51 » |
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How foolish of me. :] Just moved the setvisible below the add call and now it's rendering in time. Cheers both of you for your help!
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GabrielBailey74
Full Member Posts: 157 Medals: 2
Owner of Elite Demons R.I.P
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«
Reply #7 on:
2012-02-07 20:38:17 » |
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Np mate, i'm fairly newish.
Need any help drop me a pm.
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