Problem with Slick 2d Image / Graphics

[SmokeNWrite]

Hey, trying to create a simple new Image, blank, then add the graphics altered from another image and replace it with the image just made.

Sounds simple but when I've been trying to create a new image or even access any Images graphics its not been working, throwing a null error every time, real confused at this been wrecking my brain for past hour or two.

EDIT:
this is shader class with the problem in it:

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package org.background.worker; import java.util.Iterator; import javax.swing.SwingWorker; import org.background.LightProcessor; import org.model.World; import org.model.emitters.Emitter; import org.model.emitters.Light; import org.model.player.Player; import org.newdawn.slick.Color; import org.newdawn.slick.Graphics; import org.newdawn.slick.Image; /**  * Shader, for lighting.  * @author Senior  */ public class Shader extends SwingWorker<World, Void> {    private LightProcessor processor = null;        public LightProcessor getProcessor() {       return processor;    }    public void setProcessor(LightProcessor processor) {       this.processor = processor;    }    public Shader(LightProcessor processor) {       this.setProcessor(processor);    }    @Override    protected World doInBackground() throws Exception {       if(processor.getWorld() == null)           return null;       World world = this.getProcessor().getWorld();       Player player = world.getPlayer();       if(player == null)          return null;       if(world.getLightEmitters().size() > 0) {          for(Iterator<Emitter> it$ = world.getLightEmitters().descendingIterator(); it$.hasNext();) {             Light l = (Light) it$.next();             if(l == null)                continue;             if(!l.getPosition().isWithin(player.getPosition(), (int)l.getRange()))                continue;             if(player.getIcon() == null)                continue;                         try {                Image image = null;                image = world.getBlank();                if(image == null)                   continue;                image = image.getScaledCopy(player.getIcon().getWidth(), player.getIcon().getHeight());                if(image == null)                   continue;                //Next line is problem line.                Graphics g = image.getGraphics();                if(g == null)                   continue;                Image pixel = null;                                for(int h = 0; h < player.getIcon().getHeight(); h++) {                   for(int w = 0; w < player.getIcon().getWidth(); w++) {                      pixel = player.getIcon().getSubImage(w, h, 1, 1);                      g.drawImage(pixel, w, h, Color.red);                   }                }                                player.setIcon(image);             } catch(Exception e) {                e.printStackTrace();             }          }       }       return world;    }     }

In theory it should work but can't find the graphics here is the error:

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java.lang.NullPointerException    at org.newdawn.slick.opengl.pbuffer.GraphicsFactory.init(GraphicsFactory.java:40)    at org.newdawn.slick.opengl.pbuffer.GraphicsFactory.createGraphics(GraphicsFactory.java:120)    at org.newdawn.slick.opengl.pbuffer.GraphicsFactory.getGraphicsForImage(GraphicsFactory.java:91)    at org.newdawn.slick.Image.getGraphics(Image.java:397)    at org.background.worker.Shader.doInBackground(Shader.java:62)    at org.background.worker.Shader.doInBackground(Shader.java:1)    at javax.swing.SwingWorker$1.call(Unknown Source)    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)    at java.util.concurrent.FutureTask.run(Unknown Source)    at javax.swing.SwingWorker.run(Unknown Source)    at org.background.LightProcessor.run(LightProcessor.java:37)    at java.util.TimerThread.mainLoop(Unknown Source)    at java.util.TimerThread.run(Unknown Source)

And here is where the Image 'blank' is set:

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public World(Main main) {       this.setMain(main);       //Set up workers.       this.setProcessor(new Processor(this));       this.setLightProcessor(new LightProcessor(this));             try {          this.setBlank(new Image("./data/blank.png", false, Image.FILTER_LINEAR)); ....       } catch(SlickException e) {          e.printStackTrace();       }    }

The world is initialized in the init() method of Main extends BasicGame.

Any ideas?

Peace.

[aazimon]

Is the image object null? If so it may not be finding the image. How are you loading the image?

[SmokeNWrite]

Was just trying to create a blank Image eg new Image(256, 256) to draw graphics on and create a image.
The image is throwing a null at the moment but the graphics also does.
I don't get what's happening the principle is simple.
I've tried numerous different ways, ImageBuffer, loading a actual Image it all seems to be obsolete.



Peace

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[yuma]

I think the problem is in the constructor of Image() (in the backtrace you see org.newdawn.slick.Image.<init>)

Are you sure player.getIcon().getWidth() and player.getIcon().getHeight() return the right size?

[SmokeNWrite]

Pretty sure and I've tried different constructors of Image and even images that I know work.
When I try get Graphics from the players icon that would throw a null too.

Even the graphics I use to paint the images if I try setting that and using it there it still doesn't work.
Rather confusing me.

[ra4king]

This looks like an old LWJGL bug I've seen a while ago. Are you using the latest version?

[SmokeNWrite]

I thought I was I'll download new LWJGL
Thanks mate.

[SmokeNWrite]

Well I updated my LWJGL from 2.8.3 - 2.8.4 and downloaded (newer?) version of Slick.
Still doesn't work :/




Help?

[yuma]

Is your OpenGL context created? I think with LWJGL you have to call Display.create(), but it is some time since I last used it.

Other thing I could think of is enabling textures in OpenGL:

1	import org.lwjgl.opengl.GL11.glEnable(GL11.GL_TEXTURE_2D);

[SmokeNWrite]

Is your OpenGL context created? I think with LWJGL you have to call Display.create(), but it is some time since I last used it.

Other thing I could think of is enabling textures in OpenGL:

1	import org.lwjgl.opengl.GL11.glEnable(GL11.GL_TEXTURE_2D);

Tried both don't seem to work.
This my initialize method;

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[yuma]

Ooops, I forgot you are using Slick. I have never used it (except for the utils to load PNG textures).

Some random things that probably wont work (sorry :-():

• Do you try to create the image AFTER this.getApp().start() is called?
• The init() method is of a class inherited from org.newdawn.slick.BasicGame? Although I don't think it's relevant for this error, you could append the @Override tag to it, so you get a warning if it doesn't override for some reason.
• If your class is inherited from *.BasicGame, do you call the super() constructor on your constructor?

[SmokeNWrite]

Ooops, I forgot you are using Slick. I have never used it (except for the utils to load PNG textures).

Some random things that probably wont work (sorry :-():

• Do you try to create the image AFTER this.getApp().start() is called?
• The init() method is of a class inherited from org.newdawn.slick.BasicGame? Although I don't think it's relevant for this error, you could append the @Override tag to it, so you get a warning if it doesn't override for some reason.
• If your class is inherited from *.BasicGame, do you call the super() constructor on your constructor?

Yeah I create after this.getApp().start() and the init method of that is not thats in Main which has the superclass BasicGame and it is calling Super(String).
Really not sure, if I was in java2d this would be easy.
But slick is awesome ¬.¬

[H3rnst]

First of all I'd like to say that I'm a complete newbie. Perhaps that's why I find something odd in the next piece of code:

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try {     Image image = null;     try {         image = new Image(256,256);     } catch (SlickException se) {se.printStackTrace(); } //This is the line I'm talking about. What's the purpose of this? image.getScaledCopy(player.getIcon.getWidth(), player.getIcon.getHeight()); Graphics g = image.getGraphics(); Image pixel = null;

You're not setting another Image with the return of getScaledCopy(). Does this method sets 'image' to it's scaled copy?

Anyway I don't think it has something to do with your problem. But I do think that it might be a variable scope problem. Have you tried creating the 'image' outside the method and initializing it inside?

[SmokeNWrite]

First of all I'd like to say that I'm a complete newbie. Perhaps that's why I find something odd in the next piece of code:

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try {     Image image = null;     try {         image = new Image(256,256);     } catch (SlickException se) {se.printStackTrace(); } //This is the line I'm talking about. What's the purpose of this? image.getScaledCopy(player.getIcon.getWidth(), player.getIcon.getHeight()); Graphics g = image.getGraphics(); Image pixel = null;

You're not setting another Image with the return of getScaledCopy(). Does this method sets 'image' to it's scaled copy?

Anyway I don't think it has something to do with your problem. But I do think that it might be a variable scope problem. Have you tried creating the 'image' outside the method and initializing it inside?

Oh no that was an accident I forgot to put image = image.getScaledCopy().
Yeah the image I have tried that the image in first post is made in init().
Yet again I'm just not sure what's going on, should be simple.

[H3rnst]

You tried this:

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public void init(){     Image image; } public void render(Graphics g){     image = new Image(256,256); }

Or this (this is what I meant)

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Image image; public void init(){     image = new Image(256,256); } public void render(Graphics g){     image.resizeOrDrawThisImage(); }

[SmokeNWrite]

This is in render and the image is created in init()



Window is crashed..

[sproingie]

It would help if you pasted your actual code instead of screenshots.

[GabrielBailey74]

Just rolled out of bed so I could be wrong/late.

Define the variable you'd like to use to connect a image to "Sprite".
Define the image/path, than link it to that Sprite variable.
Than render that Sprite variable after linking the Image to it.

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public BufferedImage Sprite; public ImageIcon player = new ImageIcon("path/to/file.png");    public void paint(Graphics g) {       Sprite = player.getImage();       g.drawIage(Sprite, 20, 20, null);    }

Hope it helps some

[ra4king]

Yeah just post an SSCCE please

[SmokeNWrite]

Just rolled out of bed so I could be wrong/late.

Define the variable you'd like to use to connect a image to "Sprite".
Define the image/path, than link it to that Sprite variable.
Than render that Sprite variable after linking the Image to it.

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public BufferedImage Sprite; public ImageIcon player = new ImageIcon("path/to/file.png");    public void paint(Graphics g) {       Sprite = player.getImage();       g.drawIage(Sprite, 20, 20, null);    }

Hope it helps some

Its slick not java 2d mate.

And i'll edit my thread with sscce in a minute.

edit; updated.

[ra4king]

This is line 40 in GraphicsFactory:

1	fbo = GLContext.getCapabilities().GL_EXT_framebuffer_object;

I have no idea how a NullPointer can be thrown there, unless this is an LWJGL bug where GLContext.getCapabilities() returns null.

[SmokeNWrite]

This is line 40 in GraphicsFactory:

1	fbo = GLContext.getCapabilities().GL_EXT_framebuffer_object;

I have no idea how a NullPointer can be thrown there, unless this is an LWJGL bug where GLContext.getCapabilities() returns null.

Exactly what I mean, the error is totally confusing and shouldn't happen its a pretty simple procedure I'm trying and I have tried several ways around which have also failed.

I can't paste anymore code neither cause I ain't at home.
Would really appreciate it if somebody could figure this out.
Peacee

[Matthias]

GLContext.getCapabilities() return null when the current thread has no GL context active.

[ra4king]

*FACEPALM* Of course!

@OP
You're loading that image from another thread! You should do everything on the same thread as the rendering thread and after the GL Context has been initialized

[SmokeNWrite]

*FACEPALM* Of course!

@OP
You're loading that image from another thread! You should do everything on the same thread as the rendering thread and after the GL Context has been initialized

Surprisingly I already thought of it but never did try it, I'll just make a trigger or something that I can set in that thread then activate in the other thread.

Nice one mate (:

EDIT:
Wait don't know if that'll work because I tried getting graphics of a Image in render() and it makes the game freeze.
So strange... :/

[SmokeNWrite]

Stilll not fixed!

Peace..

[ra4king]

Any more info you can give us about this?

[SmokeNWrite]

Not really sure what else there is to say everything else works and this would be simple in java2d.

There is a converter but then I would have to convert back lol

Peace