getPickRay NPE

Troubleshooting General Help
1

I am getting a NullPointerException when attempting to use getPickRay


   public void GetTouched(float x, float y)
   {
      Ray ResultsRay = ds.getPickRay(new Vector2f(x,y), true, null);
      ...
   }



ds is the DisplaySystem I previously used .createCanvas on in order to get the canvas I am clicking on.

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
   at org.lwjgl.opengl.GL11.glLoadIdentity(GL11.java:1849)
   at com.jme.renderer.lwjgl.LWJGLCamera.doFrameChange(LWJGLCamera.java:232)
   at com.jme.renderer.lwjgl.LWJGLCamera.getModelViewMatrix(LWJGLCamera.java:272)
   at com.jme.renderer.AbstractCamera.checkViewProjection(AbstractCamera.java:1004)
   at com.jme.renderer.AbstractCamera.getWorldCoordinates(AbstractCamera.java:956)
   at com.jme.system.DisplaySystem.getWorldCoordinates(DisplaySystem.java:754)
   at com.jme.system.DisplaySystem.getPickRay(DisplaySystem.java:789)



The line in getPickRay is

DisplaySystem.getDisplaySystem().getWorldCoordinates(screenPosition, 0, store.origin);



but it seems like the problem traces back to this:

GL11.glLoadIdentity();



Do I need to do something special before using getPickRay?  Everything displays fine on the canvas.

2

Whenever I see a GL error the first question I ask - was what I did thread-safe? Was the code executed in GL thread? You might want to double-check that

3
Mindgamer said:

Whenever I see a GL error the first question I ask - was what I did thread-safe? Was the code executed in GL thread? You might want to double-check that


Just to be absolutely sure I removed the thread repainting the canvas, and set simpleUpdate to not run any code during the time GetTouched was running.  I still get the same error.  Is there a part of jme that is constantly accessing the part throwing my error - or is it possible this is not a thread-safe issue?


Edit:
I moved all my functions etc to using a StandardGame and they work fine now.  Either there is a weird threading issue with the canvas implementation that I am not seeing, or the way canvas is implemented in jme is buggy.
4

I saw the example moshad posted in this thread recently, and thought I’d take 5 minutes and hack a quick test into it - to see if it was just something wrong with my code.  It is still possible I messed up in the way I implemented it, but here is a working example of the problem:



http://www.tsourceweb.com/files/pickraytest.zip



Even though I am now using StandardGame and it works fine, I would still like to know if I am doing something improperly, or if it really is a problem in the jme code.