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[ChrisE]

Marvin,

This one is pretty straightforward.

The Bug
The bug was found calling RenderLoop.begin() and RenderLoop.end() repeatedly in response to a setVisible call. This is not right, I should've been using pauseRendering/resumeRendering, etc. etc.

That said, what happens the second time begin() is called is that it fails due to RenderLoop.getThread() returning non-null and the object deciding it doesn't need a "redundant" begin() call.


The Problem
After calling RenderLoop.end(), RenderLoop.super.end() (i.e., UpdatingThread.end()) is called, which sets isStopping to true, which kills the thread later in the UpdatingThread.loop() method. The containing method UpdatingThread.run() then sets UpdatingThread.thread to null.

In theory, this should set the derived RenderLoop.thread to null as well, thus allowing RenderLoop.begin() to be called multiple times.

However, on line 146 of RenderLoop.java we declare a private Thread variable, and so the expected behavior of using the superclass methods to control the thread does not work--specifically, we see that the thread from the superclass is set to null and so forth dutifully, but the allocated thread in RenderLoop is never touched when RenderLoop.end() is called.

And that is why you can't use RenderLoop.begin() and RenderLoop.end() back-to-back-to-back.

The Solution
I think you can just delete the private Thread member variable in RenderLoop, and defer to the super class's thread member variable.

EDIT: You'll have to go to line 301 of UpdatingThread.java and change the visibility of the thread member from 'private' to 'protected'.

[ChrisE]

Update! Patched it in my code, and it runs fine now.

If anyone is interested, here's the patch:

Code:

Index: RenderLoop.java
===================================================================
--- RenderLoop.java (revision 1844)
+++ RenderLoop.java (working copy)
@@ -143,7 +143,7 @@
     private Xith3DEnvironment x3dEnv = null;
     
     private StopOperation stopOperation = null;
-    private Thread thread = null;
+    //private Thread thread = null;
     
     /**
      * @return the RunMode this RenderLoop is running in.
Index: UpdatingThread.java
===================================================================
--- UpdatingThread.java (revision 1844)
+++ UpdatingThread.java (working copy)
@@ -298,7 +298,8 @@
     private long iterations = -1L;
     private FPSLimiter fpsLimiter = new DefaultFPSLimiter();
     
-    private Thread thread = null;
+    protected Thread thread = null;
+   
     private boolean isStopping = false;
     
     private long minItTime;

[Marvin Fröhlich]

Thanks. Good patch.

[ChrisE]

Glad I could be of help!