Fix Bug 669: Recursive GLContext makeCurrent()/release()

Culprit:
  GLContext's makeCurrent() didn't clear the boolean flag 'unlockContextAndSurface'
  in case the context is already current (-> recursion).
  Above case was detected within a code block tailed by a finally block,
  which acted on mentioned flag, i.e. called lock.unlock() and hence decremented the lock count
  even though the method return w/ successful state.

  Fixed.

Added debug code:
  GLContext.release() debug code (DEBUG | TRACE_SWITCH),
  recording stack trace of last release() call, which is dumped in case no current was current.

Added 2 unit tests:
  - Simple recursive GLContext makeCurrent()/release() from within GLEventListener's display().
    Test also validates lock count and lock ownership.

  - GLAutoDrawable display() of another GLAutoDrawable
    from within GLEventListener's display(..).

6 files changed, 368 insertions, 39 deletions

diff --git a/make/scripts/tests.sh b/make/scripts/tests.sh
index 9e76b314c..46e6c63a9 100755
--- a/make/scripts/tests.sh
+++ b/make/scripts/tests.sh
@@ -89,6 +89,7 @@ function jrun() {
     #D_ARGS="-Djogl.debug.FBObject"
     #D_ARGS="-Djogl.debug.GLSLCode"
     #D_ARGS="-Djogl.debug.GLSLCode -Djogl.debug.DebugGL -Djogl.debug.TraceGL"
+    #D_ARGS="-Djogl.debug.GLContext.TraceSwitch"
     #D_ARGS="-Djogl.debug.FixedFuncPipeline -Djogl.debug.GLSLCode"
     #D_ARGS="-Djogl.debug.FixedFuncPipeline -Djogl.debug.GLSLState"
     #D_ARGS="-Djogl.debug.FixedFuncPipeline"
@@ -277,6 +278,8 @@ function testawtswt() {
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLContextSurfaceLockNEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLDebug00NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLDebug01NEWT $*
+#testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestBug669RecursiveGLContext01NEWT $*
+testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestBug669RecursiveGLContext02NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextListNEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextListNEWT2 $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES1NEWT $*
@@ -481,7 +484,7 @@ function testawtswt() {
 #testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestTransformFeedbackVaryingsBug407NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestGLSLSimple01NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestGLSLShaderState01NEWT $*
-testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestGLSLShaderState02NEWT $*
+#testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestGLSLShaderState02NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.glsl.TestRulerNEWT01 $*
 
 #
diff --git a/src/jogl/classes/javax/media/opengl/GLContext.java b/src/jogl/classes/javax/media/opengl/GLContext.java
index 8cc29f1f2..455f2d70d 100644
--- a/src/jogl/classes/javax/media/opengl/GLContext.java
+++ b/src/jogl/classes/javax/media/opengl/GLContext.java
@@ -103,6 +103,7 @@ public abstract class GLContext {
   
   public static final boolean DEBUG = Debug.debug("GLContext");
   public static final boolean TRACE_SWITCH = Debug.isPropertyDefined("jogl.debug.GLContext.TraceSwitch", true);
+  public static final boolean DEBUG_TRACE_SWITCH = DEBUG || TRACE_SWITCH;  
 
   /** Reflects property jogl.debug.DebugGL. If true, the debug pipeline is enabled at context creation. */
   public static final boolean DEBUG_GL = Debug.isPropertyDefined("jogl.debug.DebugGL", true);
@@ -414,6 +415,16 @@ public abstract class GLContext {
     }
   }
 
+  /** Returns a String representation of the {@link #makeCurrent()} result. */
+  public static final String makeCurrentResultToString(int res) {
+      switch(res) {
+          case CONTEXT_NOT_CURRENT:   return "CONTEXT_NOT_CURRENT";
+          case CONTEXT_CURRENT:       return "CONTEXT_CURRENT";
+          case CONTEXT_CURRENT_NEW:   return "CONTEXT_NOT_CURRENT";
+          default: return "INVALID_VALUE";
+      }
+  }
+
   /**
    * Sets the thread-local variable returned by {@link #getCurrent}
    * and has no other side-effects. For use by third parties adding
diff --git a/src/jogl/classes/jogamp/opengl/GLContextImpl.java b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
index d960883d5..f2c2cfada 100644
--- a/src/jogl/classes/jogamp/opengl/GLContextImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
@@ -49,6 +49,7 @@ import com.jogamp.common.os.DynamicLookupHelper;
 import com.jogamp.common.os.Platform;
 import com.jogamp.common.util.ReflectionUtil;
 import com.jogamp.common.util.VersionNumber;
+import com.jogamp.common.util.locks.RecursiveLock;
 import com.jogamp.gluegen.runtime.FunctionAddressResolver;
 import com.jogamp.gluegen.runtime.ProcAddressTable;
 import com.jogamp.gluegen.runtime.opengl.GLNameResolver;
@@ -270,14 +271,25 @@ public abstract class GLContextImpl extends GLContext {
   @Override
   public void release() throws GLException {
     release(false);
-  }
+  }  
   private void release(boolean inDestruction) throws GLException {
     if(TRACE_SWITCH) {
-        System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - release() - force: "+inDestruction+", "+lock);
+        System.err.println(getThreadName() +": GLContext.ContextSwitch[release.0]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+", inDestruction: "+inDestruction+", "+lock);
     }
     if ( !lock.isOwner(Thread.currentThread()) ) {
-        throw new GLException("Context not current on current thread "+Thread.currentThread().getName()+": "+this);
+        final String msg = getThreadName() +": Context not current on current thread, obj " + toHexString(hashCode())+", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+", inDestruction: "+inDestruction+", "+lock;
+        if( DEBUG_TRACE_SWITCH ) {
+            System.err.println(msg);
+            if( null != lastCtxReleaseStack) {
+                System.err.print("Last release call: ");
+                lastCtxReleaseStack.printStackTrace();
+            } else {
+                System.err.println("Last release call: NONE");
+            }
+        }
+        throw new GLException(msg);
     }
+    
     Throwable drawableContextMadeCurrentException = null;
     final boolean actualRelease = ( inDestruction || lock.getHoldCount() == 1 ) && 0 != contextHandle;
     try {
@@ -298,8 +310,13 @@ public abstract class GLContextImpl extends GLContext {
       }
       drawable.unlockSurface();
       lock.unlock();
-      if(TRACE_SWITCH) {
-          System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - "+(actualRelease?"switch":"keep  ")+" - CONTEXT_RELEASE - "+lock);
+      if( DEBUG_TRACE_SWITCH ) {
+          final String msg = getThreadName() +": GLContext.ContextSwitch[release.X]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - "+(actualRelease?"switch":"keep  ")+" - "+lock;
+          lastCtxReleaseStack = new Throwable(msg);
+          if(TRACE_SWITCH) {
+              System.err.println(msg);
+              // Thread.dumpStack();
+          }
       }
     }
     if(null != drawableContextMadeCurrentException) {
@@ -307,11 +324,12 @@ public abstract class GLContextImpl extends GLContext {
     }
     
   }
+  private Throwable lastCtxReleaseStack = null;
   protected abstract void releaseImpl() throws GLException;
 
   @Override
   public final void destroy() {
-      if (DEBUG || TRACE_SWITCH) {
+      if (DEBUG_TRACE_SWITCH) {
           System.err.println(getThreadName() + ": GLContextImpl.destroy.0: obj " + toHexString(hashCode()) + ", ctx " + toHexString(contextHandle) +
                   ", surf "+toHexString(drawable.getHandle())+", isShared "+GLContextShareSet.isShared(this)+" - "+lock);
       }
@@ -328,7 +346,7 @@ public abstract class GLContextImpl extends GLContext {
               lock.lock(); // holdCount++ -> 1 - n (1: not locked, 2-n: destroy while rendering)
               if ( lock.getHoldCount() > 2 ) {
                   final String msg = getThreadName() + ": GLContextImpl.destroy: obj " + toHexString(hashCode()) + ", ctx " + toHexString(contextHandle);
-                  if (DEBUG || TRACE_SWITCH) {
+                  if (DEBUG_TRACE_SWITCH) {
                       System.err.println(msg+" - Lock was hold more than once - makeCurrent/release imbalance: "+lock);
                       Thread.dumpStack();
                   }
@@ -445,14 +463,21 @@ public abstract class GLContextImpl extends GLContext {
    */
   @Override
   public int makeCurrent() throws GLException {
-    boolean unlockContextAndDrawable = true;
-    int res = CONTEXT_NOT_CURRENT;
+    if(TRACE_SWITCH) {
+        System.err.println(getThreadName() +": GLContext.ContextSwitch[makeCurrent.0]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - "+lock);
+    }      
 
     // Note: the surface is locked within [makeCurrent .. swap .. release]
-    int lockRes = drawable.lockSurface();
+    final int lockRes = drawable.lockSurface();
     if (NativeSurface.LOCK_SURFACE_NOT_READY >= lockRes) {
+        if(DEBUG_TRACE_SWITCH) {
+            System.err.println(getThreadName() +": GLContext.ContextSwitch[makeCurrent.X1]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - Surface Not Ready - CONTEXT_NOT_CURRENT - "+lock);                        
+        }
         return CONTEXT_NOT_CURRENT;
     }
+    
+    boolean unlockContextAndSurface = true; // Must be cleared if successful, otherwise finally block will release context and surface!
+    int res = CONTEXT_NOT_CURRENT;
     try {
         if (0 == drawable.getHandle()) {
             throw new GLException("drawable has invalid handle: "+drawable);
@@ -472,8 +497,9 @@ public abstract class GLContextImpl extends GLContext {
                         // Assume we don't need to make this context current again
                         // For Mac OS X, however, we need to update the context to track resizes
                         drawableUpdatedNotify();
+                        unlockContextAndSurface = false; // success
                         if(TRACE_SWITCH) {
-                            System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - keep   - CONTEXT_CURRENT - "+lock);                        
+                            System.err.println(getThreadName() +": GLContext.ContextSwitch[makeCurrent.X2]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - keep   - CONTEXT_CURRENT - "+lock);                        
                         }
                         return CONTEXT_CURRENT;
                     } else {
@@ -481,7 +507,7 @@ public abstract class GLContextImpl extends GLContext {
                     }
                 }
                 res = makeCurrentWithinLock(lockRes);
-                unlockContextAndDrawable = CONTEXT_NOT_CURRENT == res;
+                unlockContextAndSurface = CONTEXT_NOT_CURRENT == res; // success ?
                 
                 /**
                  * FIXME: refactor dependence on Java 2D / JOGL bridge
@@ -491,28 +517,27 @@ public abstract class GLContextImpl extends GLContext {
                     }
                  */
             } catch (RuntimeException e) {
-              unlockContextAndDrawable = true;
+              unlockContextAndSurface = true;
               throw e;
             } finally {
-              if (unlockContextAndDrawable) {
+              if (unlockContextAndSurface) {
+                if(DEBUG_TRACE_SWITCH) {
+                  System.err.println(getThreadName() +": GLContext.ContextSwitch[makeCurrent.1]: Context lock.unlock() due to error, res "+makeCurrentResultToString(res)+", "+lock);
+                }
                 lock.unlock();
               }
             }
         } /* if ( drawable.isRealized() ) */
     } catch (RuntimeException e) {
-      unlockContextAndDrawable = true;
+      unlockContextAndSurface = true;
       throw e;
     } finally {
-      if (unlockContextAndDrawable) {
+      if (unlockContextAndSurface) {
         drawable.unlockSurface();
       }
     }
 
-    if (res == CONTEXT_NOT_CURRENT) {
-      if(DEBUG || TRACE_SWITCH) {
-          System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+", drawable.isRealized() "+drawable.isRealized()+" - switch - CONTEXT_NOT_CURRENT - "+lock);
-      }
-    } else {
+    if (res != CONTEXT_NOT_CURRENT) {
       setCurrent(this);
       if(res == CONTEXT_CURRENT_NEW) {
         // check if the drawable's and the GL's GLProfile are equal
@@ -531,15 +556,9 @@ public abstract class GLContextImpl extends GLContext {
             gl = gl.getContext().setGL( GLPipelineFactory.create("javax.media.opengl.Trace", null, gl, new Object[] { System.err } ) );
         }
         
-        contextRealized(true);
-        
-        if(DEBUG || TRACE_SWITCH) {
-            System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - switch - CONTEXT_CURRENT_NEW - "+lock);
-        }
-      } else if(TRACE_SWITCH) {
-         System.err.println(getThreadName() +": GLContext.ContextSwitch: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - switch - CONTEXT_CURRENT - "+lock);
+        contextRealized(true);        
       }
-
+      
       contextMadeCurrent(true);
       
       /* FIXME: refactor dependence on Java 2D / JOGL bridge
@@ -551,9 +570,12 @@ public abstract class GLContextImpl extends GLContext {
       }
       */
     }
+    if(TRACE_SWITCH) {
+        System.err.println(getThreadName() +": GLContext.ContextSwitch[makeCurrent.X3]: obj " + toHexString(hashCode()) + ", ctx "+toHexString(contextHandle)+", surf "+toHexString(drawable.getHandle())+" - switch - "+makeCurrentResultToString(res)+" - "+lock);
+    }      
     return res;
   }
-
+  
   private final int makeCurrentWithinLock(int surfaceLockRes) throws GLException {
       if (!isCreated()) {
         if(DEBUG_GL) {
@@ -584,7 +606,7 @@ public abstract class GLContextImpl extends GLContext {
                 shareWith.getDrawableImpl().unlockSurface();
             }
         }
-        if (DEBUG || TRACE_SWITCH) {
+        if (DEBUG_TRACE_SWITCH) {
             if(created) {
                 System.err.println(getThreadName() + ": Create GL context OK: obj " + toHexString(hashCode()) + ", ctx " + toHexString(contextHandle) + ", surf "+toHexString(drawable.getHandle())+" for " + getClass().getName()+" - "+getGLVersion());
                 // Thread.dumpStack();
@@ -1641,7 +1663,7 @@ public abstract class GLContextImpl extends GLContext {
       return device.getUniqueID() + "-" + toHexString(composeBits(major, minor, ctxProfileBits));
   }
 
-  protected String getContextFQN() {
+  protected final String getContextFQN() {
       return contextFQN;
   }
 
@@ -1696,19 +1718,19 @@ public abstract class GLContextImpl extends GLContext {
   //----------------------------------------------------------------------
   // Helpers for buffer object optimizations
 
-  public void setBufferSizeTracker(GLBufferSizeTracker bufferSizeTracker) {
+  public final void setBufferSizeTracker(GLBufferSizeTracker bufferSizeTracker) {
     this.bufferSizeTracker = bufferSizeTracker;
   }
 
-  public GLBufferSizeTracker getBufferSizeTracker() {
+  public final GLBufferSizeTracker getBufferSizeTracker() {
     return bufferSizeTracker;
   }
 
-  public GLBufferStateTracker getBufferStateTracker() {
+  public final GLBufferStateTracker getBufferStateTracker() {
     return bufferStateTracker;
   }
 
-  public GLStateTracker getGLStateTracker() {
+  public final GLStateTracker getGLStateTracker() {
     return glStateTracker;
   }
 
@@ -1717,10 +1739,36 @@ public abstract class GLContextImpl extends GLContext {
   // current on the OpenGL worker thread
   //
 
-  public boolean hasWaiters() {
+  /** 
+   * Returns true if the given thread is owner, otherwise false.
+   * <p>
+   * Method exists merely for code validation of {@link #isCurrent()}.
+   * </p> 
+   */
+  public final boolean isOwner(Thread thread) {
+      return lock.isOwner(thread);
+  }
+  
+  /** 
+   * Returns true if there are other threads waiting for this GLContext to {@link #makeCurrent()}, otherwise false.
+   * <p>
+   * Since method does not perform any synchronization, accurate result are returned if lock is hold - only.
+   * </p> 
+   */
+  public final boolean hasWaiters() {
     return lock.getQueueLength()>0;
   }
   
+  /** 
+   * Returns the number of hold locks. See {@link RecursiveLock#getHoldCount()} for semantics.
+   * <p>
+   * Since method does not perform any synchronization, accurate result are returned if lock is hold - only.
+   * </p> 
+   */
+  public final int getLockCount() {
+      return lock.getHoldCount();
+  }
+  
   //---------------------------------------------------------------------------
   // Special FBO hook
   //
diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
index 5b0d32353..c2b66801e 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
@@ -166,7 +166,7 @@ public abstract class X11GLXContext extends GLContextImpl {
             throw new InternalError("Given readDrawable but no driver support");
         }
     } catch (RuntimeException re) {
-        if(DEBUG || TRACE_SWITCH) {
+        if(DEBUG_TRACE_SWITCH) {
           System.err.println(getThreadName()+": Warning: X11GLXContext.glXMakeContextCurrent failed: "+re+", with "+
             "dpy "+toHexString(dpy)+
             ", write "+toHexString(writeDrawable)+
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext01NEWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext01NEWT.java
new file mode 100644
index 000000000..7b8529191
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext01NEWT.java
@@ -0,0 +1,135 @@
+/**
+ * Copyright 2013 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ * 
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ * 
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+package com.jogamp.opengl.test.junit.jogl.acore;
+
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLContext;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLProfile;
+
+import jogamp.opengl.GLContextImpl;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.jogamp.newt.opengl.GLWindow;
+import com.jogamp.opengl.test.junit.jogl.demos.es2.GearsES2;
+import com.jogamp.opengl.test.junit.util.UITestCase;
+import com.jogamp.opengl.util.Animator;
+
+/**
+ * Tests simple recursive GLContext behavior.
+ * 
+ * <p>
+ * Issues {@link GLContext#makeCurrent()} and {@link GLContext#release()}
+ * from within {@link GLEventListener#display(GLAutoDrawable)}.
+ * </p>  
+ * 
+ * <https://jogamp.org/bugzilla/show_bug.cgi?id=669>
+ */
+public class TestBug669RecursiveGLContext01NEWT extends UITestCase {
+
+  @Test(timeout=5000)
+  public void test01_Plain() {
+      test01Impl(false);
+  }
+  
+  @Test(timeout=5000)
+  public void test01_Anim() {
+      test01Impl(true);
+  }
+  
+  private void test01Impl(boolean anim) {      
+    final String profile = GLProfile.GL2ES2;
+    if(!GLProfile.isAvailable(profile)) { System.err.println(profile+" n/a"); return; }
+        
+    final GLProfile pro = GLProfile.get(profile);
+    final GLCapabilities caps = new GLCapabilities(pro);
+    final GLWindow window = GLWindow.create(caps);
+    
+    final Animator animator = new Animator();
+    if(anim) {
+        animator.add(window);
+    }
+    animator.start();
+
+    window.setSize(640, 480);    
+    window.addGLEventListener(new GLEventListener() {
+      private void makeCurrentRecursive(GLContextImpl context, int lockCount) {        
+        Assert.assertEquals(true, context.isOwner(Thread.currentThread()));
+        Assert.assertEquals(lockCount, context.getLockCount());
+        Assert.assertEquals(true, context.isCurrent());
+        
+        Assert.assertEquals(GLContext.CONTEXT_CURRENT, context.makeCurrent()); // recursive: lock +1
+        
+        Assert.assertEquals(true, context.isOwner(Thread.currentThread()));
+        Assert.assertEquals(lockCount+1, context.getLockCount());
+        Assert.assertEquals(true, context.isCurrent());
+      }
+      private void releaseRecursive(GLContextImpl context, int lockCount) {
+        Assert.assertEquals(true, context.isOwner(Thread.currentThread()));
+        Assert.assertEquals(lockCount, context.getLockCount());
+        Assert.assertEquals(true, context.isCurrent()); // still current
+        
+        context.release();  // recursive: lock -1
+        
+        Assert.assertEquals(true, context.isOwner(Thread.currentThread()));
+        Assert.assertEquals(lockCount-1, context.getLockCount());
+        Assert.assertEquals(true, context.isCurrent()); // still current
+      }
+      
+      public void reshape(final GLAutoDrawable drawable, final int x, final int y, final int width, final int height) { }
+
+      public void init(final GLAutoDrawable drawable) { }
+
+      public void dispose(final GLAutoDrawable drawable) { }
+
+      public void display(final GLAutoDrawable drawable) { 
+        final GLContextImpl context = (GLContextImpl)drawable.getContext();
+        makeCurrentRecursive(context, 1);
+        releaseRecursive(context, 2);
+      }
+    });
+    window.addGLEventListener(new GearsES2());    
+
+    try {
+        window.setVisible(true);
+        window.display();
+    } finally {
+        animator.stop();
+        window.destroy();
+    }
+  }
+  
+  public static void main(String args[]) {
+      org.junit.runner.JUnitCore.main(TestBug669RecursiveGLContext01NEWT.class.getName());
+  }
+  
+}
+
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext02NEWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext02NEWT.java
new file mode 100644
index 000000000..104355a18
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestBug669RecursiveGLContext02NEWT.java
@@ -0,0 +1,132 @@
+/**
+ * Copyright 2013 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ * 
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ * 
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+package com.jogamp.opengl.test.junit.jogl.acore;
+
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLProfile;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.jogamp.newt.opengl.GLWindow;
+import com.jogamp.opengl.test.junit.jogl.demos.es2.GearsES2;
+import com.jogamp.opengl.test.junit.jogl.demos.es2.RedSquareES2;
+import com.jogamp.opengl.test.junit.util.UITestCase;
+import com.jogamp.opengl.util.Animator;
+
+/**
+ * Tests recursive GLContext behavior.
+ * 
+ * <p>
+ * Issues {@link GLAutoDrawable#display()} of another {@link GLAutoDrawable} 
+ * from within {@link GLEventListener#display(GLAutoDrawable)}.
+ * </p>
+ *   
+ * <https://jogamp.org/bugzilla/show_bug.cgi?id=669>
+ */
+public class TestBug669RecursiveGLContext02NEWT extends UITestCase {
+
+  @Test(timeout=5000)
+  public void test01_Plain() {
+      test01Impl(false);
+  }
+  
+  @Test(timeout=5000)
+  public void test01_Anim() {
+      test01Impl(true);
+  }
+  
+  private void test01Impl(boolean anim) {      
+    final String profile = GLProfile.GL2ES2;
+    if(!GLProfile.isAvailable(profile)) { System.err.println(profile+" n/a"); return; }
+        
+    final GLProfile pro = GLProfile.get(profile);
+    final GLCapabilities caps = new GLCapabilities(pro);
+    
+    final GLWindow window2 = GLWindow.create(caps); // display() triggered by window's GLEventListener!
+    window2.setPosition(0, 0);
+    window2.setSize(200, 200);
+    window2.addGLEventListener(new RedSquareES2());
+    
+    final GLWindow window1 = GLWindow.create(caps);
+    
+    final Animator animator1 = new Animator();
+    final Animator animator2 = new Animator();
+    if(anim) {
+        animator1.add(window1);
+        animator2.add(window2);
+    }
+    animator1.start();
+    animator2.start();
+
+    window1.setPosition(250, 0);
+    window1.setSize(200, 200);
+    window1.addGLEventListener(new GLEventListener() {
+      public void reshape(final GLAutoDrawable drawable, final int x, final int y, final int width, final int height) { }
+
+      public void init(final GLAutoDrawable drawable) { }
+
+      public void dispose(final GLAutoDrawable drawable) { }
+
+      public void display(final GLAutoDrawable drawable) {
+        window2.display();
+      }
+    });
+    window1.addGLEventListener(new GearsES2());
+
+    try {
+        window2.setVisible(true);
+        window1.setVisible(true);
+        window1.display();
+        window2.display();
+        if(anim) {
+            try {
+                Thread.sleep(500);
+            } catch(InterruptedException ie) {}
+        }
+    } finally {
+        animator1.stop();
+        
+        final int win1Frames = window1.getTotalFPSFrames();
+        final int win2Frames = window2.getTotalFPSFrames();
+        System.err.println("Window1: frames "+win1Frames);
+        System.err.println("Window2: frames "+win2Frames);
+        Assert.assertTrue("Win2 frames not double the amount of Win1 frames", 2*win2Frames >= win1Frames);
+        window1.destroy();
+        window2.destroy();
+    }
+  }
+  
+  public static void main(String args[]) {
+      org.junit.runner.JUnitCore.main(TestBug669RecursiveGLContext02NEWT.class.getName());
+  }
+  
+}
+