Merge branch 'master' into stash_glyphcache

Conflicts:
	make/scripts/tests.sh
	src/jogl/classes/com/jogamp/graph/curve/OutlineShape.java
	src/jogl/classes/com/jogamp/graph/curve/Region.java
	src/jogl/classes/com/jogamp/graph/curve/opengl/GLRegion.java
	src/jogl/classes/com/jogamp/graph/curve/opengl/RegionRenderer.java
	src/jogl/classes/com/jogamp/graph/curve/opengl/Renderer.java
	src/jogl/classes/com/jogamp/graph/curve/opengl/TextRenderer.java
	src/jogl/classes/com/jogamp/graph/font/Font.java
	src/jogl/classes/com/jogamp/opengl/math/VectorUtil.java
	src/jogl/classes/jogamp/graph/curve/text/GlyphShape.java
	src/jogl/classes/jogamp/graph/curve/text/GlyphString.java
	src/jogl/classes/jogamp/graph/font/typecast/TypecastFont.java
	src/jogl/classes/jogamp/graph/font/typecast/TypecastGlyph.java
	src/jogl/classes/jogamp/graph/font/typecast/TypecastRenderer.java

1 files changed, 952 insertions, 243 deletions

diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
index c992b3cb2..0e135d5e0 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
@@ -1,22 +1,22 @@
 /*
  * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
  * Copyright (c) 2010 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:
- * 
+ *
  * - Redistribution of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
- * 
+ *
  * - Redistribution 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.
- * 
+ *
  * Neither the name of Sun Microsystems, Inc. or the names of
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
- * 
+ *
  * This software is provided "AS IS," without a warranty of any kind. ALL
  * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
  * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
@@ -29,11 +29,11 @@
  * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
  * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
  * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
- * 
+ *
  * You acknowledge that this software is not designed or intended for use
  * in the design, construction, operation or maintenance of any nuclear
  * facility.
- * 
+ *
  * Sun gratefully acknowledges that this software was originally authored
  * and developed by Kenneth Bradley Russell and Christopher John Kline.
  */
@@ -41,34 +41,52 @@
 package jogamp.opengl;
 
 import java.util.ArrayList;
+import java.util.List;
 import java.util.HashSet;
 
+import javax.media.nativewindow.NativeSurface;
+import javax.media.nativewindow.NativeWindowException;
+import javax.media.nativewindow.ProxySurface;
+import javax.media.nativewindow.UpstreamSurfaceHook;
+import javax.media.opengl.GL;
 import javax.media.opengl.GLAnimatorControl;
 import javax.media.opengl.GLAutoDrawable;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawable;
+import javax.media.opengl.GLDrawableFactory;
 import javax.media.opengl.GLEventListener;
 import javax.media.opengl.GLException;
+import javax.media.opengl.GLFBODrawable;
 import javax.media.opengl.GLRunnable;
-
-import com.jogamp.opengl.util.Animator;
+import javax.media.opengl.GLSharedContextSetter;
 
 /** Encapsulates the implementation of most of the GLAutoDrawable's
-    methods to be able to share it between GLCanvas and GLJPanel. */
-
+    methods to be able to share it between GLAutoDrawable implementations like GLAutoDrawableBase, GLCanvas and GLJPanel. */
 public class GLDrawableHelper {
   /** true if property <code>jogl.debug.GLDrawable.PerfStats</code> is defined. */
-  private static final boolean PERF_STATS = Debug.isPropertyDefined("jogl.debug.GLDrawable.PerfStats", true);
-    
+  private static final boolean PERF_STATS;
+
+  static {
+      Debug.initSingleton();
+      PERF_STATS = Debug.isPropertyDefined("jogl.debug.GLDrawable.PerfStats", true);
+  }
+
   protected static final boolean DEBUG = GLDrawableImpl.DEBUG;
-  private Object listenersLock = new Object();
-  private ArrayList<GLEventListener> listeners;
-  private HashSet<GLEventListener> listenersToBeInit;
+  private final Object listenersLock = new Object();
+  private final ArrayList<GLEventListener> listeners = new ArrayList<GLEventListener>();
+  private final HashSet<GLEventListener> listenersToBeInit = new HashSet<GLEventListener>();
+  private final Object glRunnablesLock = new Object();
+  private volatile ArrayList<GLRunnableTask> glRunnables = new ArrayList<GLRunnableTask>();
   private boolean autoSwapBufferMode;
-  private Thread skipContextReleaseThread;
-  private Object glRunnablesLock = new Object();
-  private ArrayList<GLRunnable> glRunnables;
+  private volatile Thread exclusiveContextThread;
+  /** -1 release, 0 nop, 1 claim */
+  private volatile int exclusiveContextSwitch;
   private GLAnimatorControl animatorCtrl;
+  private static Runnable nop = new Runnable() { @Override public void run() {} };
+
+  private GLContext sharedContext;
+  private GLAutoDrawable sharedAutoDrawable;
+
 
   public GLDrawableHelper() {
     reset();
@@ -76,15 +94,76 @@ public class GLDrawableHelper {
 
   public final void reset() {
     synchronized(listenersLock) {
-        listeners = new ArrayList<GLEventListener>();
-        listenersToBeInit = new HashSet<GLEventListener>();
+        listeners.clear();
+        listenersToBeInit.clear();
     }
     autoSwapBufferMode = true;
-    skipContextReleaseThread = null;
+    exclusiveContextThread = null;
+    exclusiveContextSwitch = 0;
     synchronized(glRunnablesLock) {
-        glRunnables = new ArrayList<GLRunnable>();
+        glRunnables.clear();
     }
     animatorCtrl = null;
+    sharedContext = null;
+    sharedAutoDrawable = null;
+  }
+
+  public final void setSharedContext(GLContext thisContext, GLContext sharedContext) throws IllegalStateException {
+      if( null == sharedContext ) {
+          throw new IllegalStateException("Null shared GLContext");
+      }
+      if( thisContext == sharedContext ) {
+          throw new IllegalStateException("Shared GLContext same as local");
+      }
+      if( null != this.sharedContext ) {
+          throw new IllegalStateException("Shared GLContext already set");
+      }
+      if( null != this.sharedAutoDrawable ) {
+          throw new IllegalStateException("Shared GLAutoDrawable already set");
+      }
+      this.sharedContext = sharedContext;
+  }
+
+  public final void setSharedAutoDrawable(GLAutoDrawable thisAutoDrawable, GLAutoDrawable sharedAutoDrawable) throws IllegalStateException {
+      if( null == sharedAutoDrawable ) {
+          throw new IllegalStateException("Null shared GLAutoDrawable");
+      }
+      if( thisAutoDrawable == sharedAutoDrawable ) {
+          throw new IllegalStateException("Shared GLAutoDrawable same as this");
+      }
+      if( null != this.sharedContext ) {
+          throw new IllegalStateException("Shared GLContext already set");
+      }
+      if( null != this.sharedAutoDrawable ) {
+          throw new IllegalStateException("Shared GLAutoDrawable already set");
+      }
+      this.sharedAutoDrawable = sharedAutoDrawable;
+  }
+
+  /**
+   * @param shared returns the shared GLContext, based on set shared GLAutoDrawable
+   *               or GLContext. Maybe null if none is set.
+   * @return true if initialization is pending due to a set shared GLAutoDrawable or GLContext
+   *         which is not ready yet. Otherwise false.
+   */
+  public boolean isSharedGLContextPending(GLContext[] shared) {
+      final GLContext shareWith;
+      final boolean pending;
+      if ( null != sharedAutoDrawable ) {
+          final boolean allGLELInitialized;
+          if( sharedAutoDrawable instanceof GLSharedContextSetter ) {
+              allGLELInitialized = ((GLSharedContextSetter)sharedAutoDrawable).areAllGLEventListenerInitialized();
+          } else {
+              allGLELInitialized = true; // we have to assume 'yes'
+          }
+          shareWith = sharedAutoDrawable.getContext();
+          pending = null == shareWith || !shareWith.isCreated() || !allGLELInitialized;
+      } else {
+          shareWith = sharedContext;
+          pending = null != shareWith && !shareWith.isCreated();
+      }
+      shared[0] = shareWith;
+      return pending;
   }
 
   @Override
@@ -105,6 +184,207 @@ public class GLDrawableHelper {
     return sb.toString();
   }
 
+  /** Limit release calls of {@link #forceNativeRelease(GLContext)} to {@value}. */
+  private static final int MAX_RELEASE_ITER = 512;
+
+  /**
+   * Since GLContext's {@link GLContext#makeCurrent()} and {@link GLContext#release()}
+   * is recursive, a call to {@link GLContext#release()} may not natively release the context.
+   * <p>
+   * This methods continues calling {@link GLContext#release()} until the context has been natively released.
+   * </p>
+   * @param ctx
+   */
+  public static final void forceNativeRelease(GLContext ctx) {
+      int releaseCount = 0;
+      do {
+          ctx.release();
+          releaseCount++;
+          if (DEBUG) {
+              System.err.println("GLDrawableHelper.forceNativeRelease() #"+releaseCount+" -- currentThread "+Thread.currentThread()+" -> "+GLContext.getCurrent());
+          }
+      } while( MAX_RELEASE_ITER > releaseCount && ctx.isCurrent() );
+
+      if( ctx.isCurrent() ) {
+          throw new GLException("Context still current after "+MAX_RELEASE_ITER+" releases: "+ctx);
+      }
+  }
+
+  /**
+   * Switch {@link GLContext} / {@link GLDrawable} association.
+   * <p>
+   * The <code>oldCtx</code> will be destroyed if <code>destroyPrevCtx</code> is <code>true</code>,
+   * otherwise dis-associate <code>oldCtx</code> from <code>drawable</code>
+   * via {@link GLContext#setGLDrawable(GLDrawable, boolean) oldCtx.setGLDrawable(null, true);}.
+   * </p>
+   * <p>
+   * Re-associate <code>newCtx</code> with <code>drawable</code>
+   * via {@link GLContext#setGLDrawable(GLDrawable, boolean) newCtx.setGLDrawable(drawable, true);}.
+   * </p>
+   * <p>
+   * If the old or new context was current on this thread, it is being released before switching the drawable.
+   * </p>
+   * <p>
+   * No locking is being performed on the drawable, caller is required to take care of it.
+   * </p>
+   *
+   * @param drawable the drawable which context is changed
+   * @param oldCtx the old context, maybe <code>null</code>.
+   * @param destroyOldCtx if <code>true</code>, destroy the <code>oldCtx</code>
+   * @param newCtx the new context, maybe <code>null</code> for dis-association.
+   * @param newCtxCreationFlags additional creation flags if newCtx is not null and not been created yet, see {@link GLContext#setContextCreationFlags(int)}
+   *
+   * @see GLAutoDrawable#setContext(GLContext, boolean)
+   */
+  public static final void switchContext(GLDrawable drawable, GLContext oldCtx, boolean destroyOldCtx, GLContext newCtx, int newCtxCreationFlags) {
+      if( null != oldCtx ) {
+          if( destroyOldCtx ) {
+              oldCtx.destroy();
+          } else {
+              oldCtx.setGLDrawable(null, true); // dis-associate old pair
+          }
+      }
+
+      if(null!=newCtx) {
+          newCtx.setContextCreationFlags(newCtxCreationFlags);
+          newCtx.setGLDrawable(drawable, true); // re-associate new pair
+      }
+  }
+
+  /**
+   * If the drawable is not realized, OP is a NOP.
+   * <ul>
+   *  <li>release context if current</li>
+   *  <li>destroy old drawable</li>
+   *  <li>create new drawable</li>
+   *  <li>attach new drawable to context</li>
+   *  <li>make context current, if it was current</li>
+   * </ul>
+   * <p>
+   * Locking is performed via {@link GLContext#makeCurrent()} on the passed <code>context</code>.
+   * </p>
+   *
+   * @param drawable
+   * @param context maybe null
+   * @return the new drawable
+   */
+  public static final GLDrawableImpl recreateGLDrawable(GLDrawableImpl drawable, GLContext context) {
+      if( ! drawable.isRealized() ) {
+          return drawable;
+      }
+      final GLContext currentContext = GLContext.getCurrent();
+      final GLDrawableFactory factory = drawable.getFactory();
+      final NativeSurface surface = drawable.getNativeSurface();
+      final ProxySurface proxySurface = (surface instanceof ProxySurface) ? (ProxySurface)surface : null;
+
+      if( null != context ) {
+          // Ensure to sync GL command stream
+          if( currentContext != context ) {
+              context.makeCurrent();
+          }
+          context.getGL().glFinish();
+          context.setGLDrawable(null, true); // dis-associate
+      }
+
+      if(null != proxySurface) {
+          proxySurface.enableUpstreamSurfaceHookLifecycle(false);
+      }
+      try {
+          drawable.setRealized(false);
+          drawable = (GLDrawableImpl) factory.createGLDrawable(surface); // [2]
+          drawable.setRealized(true);
+      } finally {
+          if(null != proxySurface) {
+              proxySurface.enableUpstreamSurfaceHookLifecycle(true);
+          }
+      }
+
+      if(null != context) {
+          context.setGLDrawable(drawable, true); // re-association
+      }
+
+      if( null != currentContext ) {
+          currentContext.makeCurrent();
+      }
+      return drawable;
+  }
+
+  /**
+   * Performs resize operation on the given drawable, assuming it is offscreen.
+   * <p>
+   * The {@link GLDrawableImpl}'s {@link NativeSurface} is being locked during operation.
+   * In case the holder is an auto drawable or similar, it's lock shall be claimed by the caller.
+   * </p>
+   * <p>
+   * May recreate the drawable via {@link #recreateGLDrawable(GLDrawableImpl, GLContext)}
+   * in case of a a pbuffer- or pixmap-drawable.
+   * </p>
+   * <p>
+   * FBO drawables are resized w/o drawable destruction.
+   * </p>
+   * <p>
+   * Offscreen resize operation is validated w/ drawable size in the end.
+   * An exception is thrown if not successful.
+   * </p>
+   *
+   * @param drawable
+   * @param context
+   * @param newWidth the new width, it's minimum is capped to 1
+   * @param newHeight the new height, it's minimum is capped to 1
+   * @return the new drawable in case of an pbuffer/pixmap drawable, otherwise the passed drawable is being returned.
+   * @throws NativeWindowException is drawable is not offscreen or it's surface lock couldn't be claimed
+   * @throws GLException may be thrown a resize operation
+   */
+  public static final GLDrawableImpl resizeOffscreenDrawable(GLDrawableImpl drawable, GLContext context, int newWidth, int newHeight)
+          throws NativeWindowException, GLException
+  {
+      final NativeSurface ns = drawable.getNativeSurface();
+      final int lockRes = ns.lockSurface();
+      if ( NativeSurface.LOCK_SURFACE_NOT_READY >= lockRes ) {
+          throw new NativeWindowException("Could not lock surface of drawable: "+drawable);
+      }
+      boolean validateSize = true;
+      try {
+          if( ! drawable.isRealized() ) {
+              return drawable;
+          }
+          if( drawable.getChosenGLCapabilities().isOnscreen() ) {
+              throw new NativeWindowException("Drawable is not offscreen: "+drawable);
+          }
+          if( DEBUG && ( 0>=newWidth || 0>=newHeight) ) {
+              System.err.println("WARNING: Odd size detected: "+newWidth+"x"+newHeight+", using safe size 1x1. Drawable "+drawable);
+              Thread.dumpStack();
+          }
+          if( 0 >= newWidth )  { newWidth = 1; validateSize=false; }
+          if( 0 >= newHeight ) { newHeight = 1; validateSize=false; }
+          // propagate new size
+          if( ns instanceof ProxySurface ) {
+              final ProxySurface ps = (ProxySurface) ns;
+              final UpstreamSurfaceHook ush = ps.getUpstreamSurfaceHook();
+              if(ush instanceof UpstreamSurfaceHook.MutableSize) {
+                  ((UpstreamSurfaceHook.MutableSize)ush).setSize(newWidth, newHeight);
+              } else if(DEBUG) { // we have to assume UpstreamSurfaceHook contains the new size already, hence size check @ bottom
+                  System.err.println("GLDrawableHelper.resizeOffscreenDrawable: Drawable's offscreen ProxySurface n.a. UpstreamSurfaceHook.MutableSize, but "+ush.getClass().getName()+": "+ush);
+              }
+          } else if(DEBUG) { // we have to assume surface contains the new size already, hence size check @ bottom
+              System.err.println("GLDrawableHelper.resizeOffscreenDrawable: Drawable's offscreen surface n.a. ProxySurface, but "+ns.getClass().getName()+": "+ns);
+          }
+          if( drawable instanceof GLFBODrawable ) {
+              if( null != context && context.isCreated() ) {
+                  ((GLFBODrawable) drawable).resetSize(context.getGL());
+              }
+          } else {
+              drawable = GLDrawableHelper.recreateGLDrawable(drawable, context);
+          }
+      } finally {
+          ns.unlockSurface();
+      }
+      if( validateSize && ( drawable.getWidth() != newWidth || drawable.getHeight() != newHeight ) ) {
+          throw new InternalError("Incomplete resize operation: expected "+newWidth+"x"+newHeight+", has: "+drawable);
+      }
+      return drawable;
+  }
+
   public final void addGLEventListener(GLEventListener listener) {
     addGLEventListener(-1, listener);
   }
@@ -117,88 +397,296 @@ public class GLDrawableHelper {
         // GLEventListener may be added after context is created,
         // hence we earmark initialization for the next display call.
         listenersToBeInit.add(listener);
+
         listeners.add(index, listener);
     }
   }
-  
-  public final void removeGLEventListener(GLEventListener listener) {
+
+  /**
+   * Note that no {@link GLEventListener#dispose(GLAutoDrawable)} call is being issued
+   * due to the lack of a current context.
+   * Consider calling {@link #disposeGLEventListener(GLAutoDrawable, GLDrawable, GLContext, GLEventListener)}.
+   * @return the removed listener, or null if listener was not added
+   */
+  public final GLEventListener removeGLEventListener(GLEventListener listener) {
     synchronized(listenersLock) {
-        listeners.remove(listener);
         listenersToBeInit.remove(listener);
+        return listeners.remove(listener) ? listener : null;
+    }
+  }
+
+  public final GLEventListener removeGLEventListener(int index) throws IndexOutOfBoundsException {
+    synchronized(listenersLock) {
+        if(0>index) {
+            index = listeners.size()-1;
+        }
+        final GLEventListener listener = listeners.remove(index);
+        listenersToBeInit.remove(listener);
+        return listener;
+    }
+  }
+
+  public final int getGLEventListenerCount() {
+    synchronized(listenersLock) {
+        return listeners.size();
+    }
+  }
+
+  public final GLEventListener getGLEventListener(int index) throws IndexOutOfBoundsException {
+    synchronized(listenersLock) {
+        if(0>index) {
+            index = listeners.size()-1;
+        }
+        return listeners.get(index);
+    }
+  }
+
+  public final boolean areAllGLEventListenerInitialized() {
+    synchronized(listenersLock) {
+        return 0 == listenersToBeInit.size();
+    }
+  }
+
+  public final boolean getGLEventListenerInitState(GLEventListener listener) {
+    synchronized(listenersLock) {
+        return !listenersToBeInit.contains(listener);
+    }
+  }
+
+  public final void setGLEventListenerInitState(GLEventListener listener, boolean initialized) {
+    synchronized(listenersLock) {
+        if(initialized) {
+            listenersToBeInit.remove(listener);
+        } else {
+            listenersToBeInit.add(listener);
+        }
     }
   }
 
   /**
-   * Issues {@link javax.media.opengl.GLEventListener#dispose(javax.media.opengl.GLAutoDrawable)}
-   * to all listeners.
+   * Disposes the given {@link GLEventListener} via {@link GLEventListener#dispose(GLAutoDrawable)}
+   * if it has been initialized and added to this queue.
    * <p>
-   * Please consider using {@link #disposeGL(GLAutoDrawable, GLDrawable, GLContext, Runnable)}
-   * for correctness!
+   * If <code>remove</code> is <code>true</code>, the {@link GLEventListener} is removed from this drawable queue before disposal,
+   * otherwise marked uninitialized.
    * </p>
-   * @param drawable
+   * <p>
+   * Please consider using {@link #disposeGLEventListener(GLAutoDrawable, GLDrawable, GLContext, GLEventListener)}
+   * for correctness, i.e. encapsulating all calls w/ makeCurrent etc.
+   * </p>
+   * @param autoDrawable
+   * @param remove if true, the listener gets removed
+   * @return the disposed and/or removed listener, otherwise null if neither action is performed
+   */
+  public final GLEventListener disposeGLEventListener(GLAutoDrawable autoDrawable, GLEventListener listener, boolean remove) {
+      synchronized(listenersLock) {
+          if( remove ) {
+              if( listeners.remove(listener) ) {
+                  if( !listenersToBeInit.remove(listener) ) {
+                      listener.dispose(autoDrawable);
+                  }
+                  return listener;
+              }
+          } else {
+              if( listeners.contains(listener) && !listenersToBeInit.contains(listener) ) {
+                  listener.dispose(autoDrawable);
+                  listenersToBeInit.add(listener);
+                  return listener;
+              }
+          }
+      }
+      return null;
+  }
+
+  /**
+   * Disposes all added initialized {@link GLEventListener}s via {@link GLEventListener#dispose(GLAutoDrawable)}.
+   * <p>
+   * If <code>remove</code> is <code>true</code>, the {@link GLEventListener}s are removed from this drawable queue before disposal,
+   * otherwise maked uninitialized.
+   * </p>
+   * <p>
+   * Please consider using {@link #disposeAllGLEventListener(GLAutoDrawable, GLContext, boolean)}
+   * or {@link #disposeGL(GLAutoDrawable, GLContext, boolean)}
+   * for correctness, i.e. encapsulating all calls w/ makeCurrent etc.
+   * </p>
+   * @param autoDrawable
+   * @return the disposal count
    */
-  public final void dispose(GLAutoDrawable drawable) {
+  public final int disposeAllGLEventListener(GLAutoDrawable autoDrawable, boolean remove) {
+    int disposeCount = 0;
     synchronized(listenersLock) {
-        for (int i=0; i < listeners.size(); i++) {
-          listeners.get(i).dispose(drawable);
+        if( remove ) {
+            for (int count = listeners.size(); 0 < count && 0 < listeners.size(); count--) {
+              final GLEventListener listener = listeners.remove(0);
+              if( !listenersToBeInit.remove(listener) ) {
+                  listener.dispose(autoDrawable);
+                  disposeCount++;
+              }
+            }
+        } else {
+            for (int i = 0; i < listeners.size(); i++) {
+              final GLEventListener listener = listeners.get(i);
+              if( !listenersToBeInit.contains(listener) ) {
+                  listener.dispose(autoDrawable);
+                  listenersToBeInit.add(listener);
+                  disposeCount++;
+              }
+            }
         }
     }
+    return disposeCount;
   }
-  
-  private boolean init(GLEventListener l, GLAutoDrawable drawable, boolean sendReshape) {
-      if(listenersToBeInit.remove(l)) {
-          l.init(drawable);
-          if(sendReshape) {
-              reshape(l, drawable, 0, 0, drawable.getWidth(), drawable.getHeight(), true /* setViewport */, false);
+
+  /**
+   * Principal helper method which runs {@link #disposeGLEventListener(GLAutoDrawable, GLEventListener, boolean)}
+   * with the context made current.
+   * <p>
+   * If an {@link GLAnimatorControl} is being attached and the current thread is different
+   * than {@link GLAnimatorControl#getThread() the animator's thread}, it is paused during the operation.
+   * </p>
+   *
+   * @param autoDrawable
+   * @param context
+   * @param listener
+   * @param initAction
+   */
+  public final GLEventListener disposeGLEventListener(final GLAutoDrawable autoDrawable,
+                                                      final GLDrawable drawable,
+                                                      final GLContext context,
+                                                      final GLEventListener listener,
+                                                      final boolean remove) {
+      synchronized(listenersLock) {
+          // fast path for uninitialized listener
+          if( listenersToBeInit.contains(listener) ) {
+             if( remove ) {
+                 listenersToBeInit.remove(listener);
+                 return listeners.remove(listener) ? listener : null;
+             }
+             return null;
           }
-          return true;
       }
-      return false;
+      final boolean isPaused = isAnimatorAnimatingOnOtherThread() && animatorCtrl.pause();
+      final GLEventListener[] res = new GLEventListener[] { null };
+      final Runnable action = new Runnable() {
+          @Override
+          public void run() {
+              res[0] = disposeGLEventListener(autoDrawable, listener, remove);
+          }
+      };
+      invokeGL(drawable, context, action, nop);
+
+      if(isPaused) {
+          animatorCtrl.resume();
+      }
+      return res[0];
   }
 
-  public final void init(GLAutoDrawable drawable) {
-    synchronized(listenersLock) {
-        for (int i=0; i < listeners.size(); i++) {
-          final GLEventListener listener = listeners.get(i) ;
+  /**
+   * Principal helper method which runs {@link #disposeAllGLEventListener(GLAutoDrawable, boolean)}
+   * with the context made current.
+   * <p>
+   * If an {@link GLAnimatorControl} is being attached and the current thread is different
+   * than {@link GLAnimatorControl#getThread() the animator's thread}, it is paused during the operation.
+   * </p>
+   *
+   * @param autoDrawable
+   * @param context
+   * @param remove
+   */
+  public final void disposeAllGLEventListener(final GLAutoDrawable autoDrawable,
+                                              final GLDrawable drawable,
+                                              final GLContext context,
+                                              final boolean remove) {
 
-          // If make current ctx, invoked by invokGL(..), results in a new ctx, init gets called.
-          // This may happen not just for initial setup, but for ctx recreation due to resource change (drawable/window),
-          // hence the must always be initialized unconditional.
-          listenersToBeInit.add(listener);
+      final boolean isPaused = isAnimatorAnimatingOnOtherThread() && animatorCtrl.pause();
 
-          if ( ! init( listener, drawable, false ) ) {
-            throw new GLException("GLEventListener "+listener+" already initialized: "+drawable);
+      final Runnable action = new Runnable() {
+          @Override
+          public void run() {
+              disposeAllGLEventListener(autoDrawable, remove);
           }
+      };
+      invokeGL(drawable, context, action, nop);
+
+      if(isPaused) {
+          animatorCtrl.resume();
+      }
+  }
+
+  private final void init(GLEventListener l, GLAutoDrawable drawable, boolean sendReshape, boolean setViewport) {
+      l.init(drawable);
+      if(sendReshape) {
+          reshape(l, drawable, 0, 0, drawable.getWidth(), drawable.getHeight(), setViewport, false /* checkInit */);
+      }
+  }
+
+  /**
+   * The default init action to be called once after ctx is being created @ 1st makeCurrent().
+   * @param sendReshape set to true if the subsequent display call won't reshape, otherwise false to avoid double reshape.
+   **/
+  public final void init(GLAutoDrawable drawable, boolean sendReshape) {
+    synchronized(listenersLock) {
+        final ArrayList<GLEventListener> _listeners = listeners;
+        final int listenerCount = _listeners.size();
+        if( listenerCount > 0 ) {
+            for (int i=0; i < listenerCount; i++) {
+              final GLEventListener listener = _listeners.get(i) ;
+
+              // If make ctx current, invoked by invokGL(..), results in a new ctx, init gets called.
+              // This may happen not just for initial setup, but for ctx recreation due to resource change (drawable/window),
+              // hence it must be called unconditional, always.
+              listenersToBeInit.remove(listener); // remove if exist, avoiding dbl init
+              init( listener, drawable, sendReshape, 0==i /* setViewport */);
+            }
+        } else {
+            // Expose same GL initialization if not using GLEventListener
+            drawable.getGL().glViewport(0, 0, drawable.getWidth(), drawable.getHeight());
         }
     }
   }
 
   public final void display(GLAutoDrawable drawable) {
     displayImpl(drawable);
-    if(!execGLRunnables(drawable)) {
-        displayImpl(drawable);  
+    if( glRunnables.size()>0 && !execGLRunnables(drawable) ) { // glRunnables volatile OK; execGL.. only executed if size > 0
+        displayImpl(drawable);
     }
   }
-  private void displayImpl(GLAutoDrawable drawable) {
+  private final void displayImpl(GLAutoDrawable drawable) {
       synchronized(listenersLock) {
-          for (int i=0; i < listeners.size(); i++) {
-            final GLEventListener listener = listeners.get(i) ;
-            // GLEventListener may need to be init, 
+          final ArrayList<GLEventListener> _listeners = listeners;
+          final int listenerCount = _listeners.size();
+          for (int i=0; i < listenerCount; i++) {
+            final GLEventListener listener = _listeners.get(i) ;
+            // GLEventListener may need to be init,
             // in case this one is added after the realization of the GLAutoDrawable
-            init( listener, drawable, true ) ; 
+            if( listenersToBeInit.remove(listener) ) {
+                init( listener, drawable, true /* sendReshape */, listenersToBeInit.size() + 1 == listenerCount /* setViewport if 1st init */ );
+            }
             listener.display(drawable);
           }
       }
   }
 
-  private void reshape(GLEventListener listener, GLAutoDrawable drawable,
-                       int x, int y, int width, int height, boolean setViewport, boolean checkInit) {
+  private final void reshape(GLEventListener listener, GLAutoDrawable drawable,
+                             int x, int y, int width, int height, boolean setViewport, boolean checkInit) {
     if(checkInit) {
-        // GLEventListener may need to be init, 
-        // in case this one is added after the realization of the GLAutoDrawable      
-        init( listener, drawable, false ) ;
+        // GLEventListener may need to be init,
+        // in case this one is added after the realization of the GLAutoDrawable
+        synchronized(listenersLock) {
+            if( listenersToBeInit.remove(listener) ) {
+                listener.init(drawable);
+            }
+        }
     }
     if(setViewport) {
+        final GL gl = drawable.getGL();
+        final int glerr0 = gl.glGetError();
+        if( GL.GL_NO_ERROR != glerr0 ) {
+            System.err.println("Info: GLDrawableHelper.reshape: pre-exisiting GL error 0x"+Integer.toHexString(glerr0));
+            if(DEBUG) {
+                Thread.dumpStack();
+            }
+        }
         drawable.getGL().glViewport(x, y, width, height);
     }
     listener.reshape(drawable, x, y, width, height);
@@ -207,30 +695,51 @@ public class GLDrawableHelper {
   public final void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
     synchronized(listenersLock) {
         for (int i=0; i < listeners.size(); i++) {
-          reshape((GLEventListener) listeners.get(i), drawable, x, y, width, height, 0==i, true);
+          reshape(listeners.get(i), drawable, x, y, width, height, 0==i /* setViewport */, true /* checkInit */);
         }
     }
   }
 
-  private boolean execGLRunnables(GLAutoDrawable drawable) {
+  private final boolean execGLRunnables(GLAutoDrawable drawable) { // glRunnables.size()>0
     boolean res = true;
-    if(glRunnables.size()>0) {
+    // swap one-shot list asap
+    final ArrayList<GLRunnableTask> _glRunnables;
+    synchronized(glRunnablesLock) {
+        if(glRunnables.size()>0) {
+            _glRunnables = glRunnables;
+            glRunnables = new ArrayList<GLRunnableTask>();
+        } else {
+            _glRunnables = null;
+        }
+    }
+
+    if(null!=_glRunnables) {
+        for (int i=0; i < _glRunnables.size(); i++) {
+            res = _glRunnables.get(i).run(drawable) && res;
+        }
+    }
+    return res;
+  }
+
+  public final void flushGLRunnables() {
+    if(glRunnables.size()>0) { // volatile OK
         // swap one-shot list asap
-        ArrayList<GLRunnable> _glRunnables = null;
+        final ArrayList<GLRunnableTask> _glRunnables;
         synchronized(glRunnablesLock) {
             if(glRunnables.size()>0) {
                 _glRunnables = glRunnables;
-                glRunnables = new ArrayList<GLRunnable>();
+                glRunnables = new ArrayList<GLRunnableTask>();
+            } else {
+                _glRunnables = null;
             }
         }
-        
+
         if(null!=_glRunnables) {
             for (int i=0; i < _glRunnables.size(); i++) {
-              res = _glRunnables.get(i).run(drawable) && res;
+                _glRunnables.get(i).flush();
             }
         }
     }
-    return res;
   }
 
   public final void setAnimator(GLAnimatorControl animator) throws GLException {
@@ -248,15 +757,15 @@ public class GLDrawableHelper {
     }
   }
 
-  public final boolean isExternalAnimatorRunning() {
+  public final boolean isAnimatorStartedOnOtherThread() {
     return ( null != animatorCtrl ) ? animatorCtrl.isStarted() && animatorCtrl.getThread() != Thread.currentThread() : false ;
   }
 
-  public final boolean isAnimatorRunning() {
+  public final boolean isAnimatorStarted() {
     return ( null != animatorCtrl ) ? animatorCtrl.isStarted() : false ;
   }
 
-  public final boolean isExternalAnimatorAnimating() {
+  public final boolean isAnimatorAnimatingOnOtherThread() {
     return ( null != animatorCtrl ) ? animatorCtrl.isAnimating() && animatorCtrl.getThread() != Thread.currentThread() : false ;
   }
 
@@ -264,17 +773,35 @@ public class GLDrawableHelper {
     return ( null != animatorCtrl ) ? animatorCtrl.isAnimating() : false ;
   }
 
-  public final void invoke(GLAutoDrawable drawable, boolean wait, GLRunnable glRunnable) {
-    if( null == drawable || null == glRunnable ) {
-        return;
+  /**
+   * <p>
+   * If <code>wait</code> is <code>true</code> the call blocks until the <code>glRunnable</code>
+   * has been executed.<p>
+   * <p>
+   * If <code>wait</code> is <code>true</code> <b>and</b>
+   * {@link GLDrawable#isRealized()} returns <code>false</code> <i>or</i> {@link GLAutoDrawable#getContext()} returns <code>null</code>,
+   * the call is ignored and returns <code>false</code>.<br>
+   * This helps avoiding deadlocking the caller.
+   * </p>
+   *
+   * @param drawable the {@link GLAutoDrawable} to be used
+   * @param wait if <code>true</code> block until execution of <code>glRunnable</code> is finished, otherwise return immediatly w/o waiting
+   * @param glRunnable the {@link GLRunnable} to execute within {@link #display()}
+   * @return <code>true</code> if the {@link GLRunnable} has been processed or queued, otherwise <code>false</code>.
+   */
+  public final boolean invoke(GLAutoDrawable drawable, boolean wait, GLRunnable glRunnable) {
+    if( null == glRunnable || null == drawable ||
+        wait && ( !drawable.isRealized() || null==drawable.getContext() ) ) {
+        return false;
     }
-    Throwable throwable = null;
+
     GLRunnableTask rTask = null;
     Object rTaskLock = new Object();
+    Throwable throwable = null;
     synchronized(rTaskLock) {
-        boolean deferred;
+        final boolean deferred;
         synchronized(glRunnablesLock) {
-            deferred = isExternalAnimatorAnimating();
+            deferred = isAnimatorAnimatingOnOtherThread();
             if(!deferred) {
                 wait = false; // don't wait if exec immediatly
             }
@@ -299,6 +826,60 @@ public class GLDrawableHelper {
             }
         }
     }
+    return true;
+  }
+
+  public final boolean invoke(GLAutoDrawable drawable, boolean wait, List<GLRunnable> newGLRunnables) {
+    if( null == newGLRunnables || newGLRunnables.size() == 0 || null == drawable ||
+        wait && ( !drawable.isRealized() || null==drawable.getContext() ) ) {
+        return false;
+    }
+
+    final int count = newGLRunnables.size();
+    GLRunnableTask rTask = null;
+    Object rTaskLock = new Object();
+    Throwable throwable = null;
+    synchronized(rTaskLock) {
+        final boolean deferred;
+        synchronized(glRunnablesLock) {
+            deferred = isAnimatorAnimatingOnOtherThread() || !drawable.isRealized();
+            if(!deferred) {
+                wait = false; // don't wait if exec immediately
+            }
+            for(int i=0; i<count-1; i++) {
+                glRunnables.add( new GLRunnableTask(newGLRunnables.get(i), null, false) );
+            }
+            rTask = new GLRunnableTask(newGLRunnables.get(count-1),
+                                       wait ? rTaskLock : null,
+                                       wait  /* catch Exceptions if waiting for result */);
+            glRunnables.add(rTask);
+        }
+        if( !deferred ) {
+            drawable.display();
+        } else if( wait ) {
+            try {
+                rTaskLock.wait(); // free lock, allow execution of rTask
+            } catch (InterruptedException ie) {
+                throwable = ie;
+            }
+            if(null==throwable) {
+                throwable = rTask.getThrowable();
+            }
+            if(null!=throwable) {
+                throw new RuntimeException(throwable);
+            }
+        }
+    }
+    return true;
+  }
+
+  public final void enqueue(GLRunnable glRunnable) {
+    if( null == glRunnable) {
+        return;
+    }
+    synchronized(glRunnablesLock) {
+        glRunnables.add( new GLRunnableTask(glRunnable, null, false) );
+    }
   }
 
   public final void setAutoSwapBufferMode(boolean enable) {
@@ -309,25 +890,74 @@ public class GLDrawableHelper {
     return autoSwapBufferMode;
   }
 
+  private final String getExclusiveContextSwitchString() {
+      return 0 == exclusiveContextSwitch ? "nop" : ( 0 > exclusiveContextSwitch ? "released" : "claimed" ) ;
+  }
+
   /**
-   * @param t the thread for which context release shall be skipped, usually the animation thread,
-   *          ie. {@link Animator#getThread()}.
-   * @deprecated this is an experimental feature, 
-   *             intended for measuring performance in regards to GL context switch
-   *             and only being used if {@link #PERF_STATS} is enabled
-   *             by defining property <code>jogl.debug.GLDrawable.PerfStats</code>.
+   * Dedicates this instance's {@link GLContext} to the given thread.<br/>
+   * The thread will exclusively claim the {@link GLContext} via {@link #display()} and not release it
+   * until {@link #destroy()} or <code>setExclusiveContextThread(null)</code> has been called.
+   * <p>
+   * Default non-exclusive behavior is <i>requested</i> via <code>setExclusiveContextThread(null)</code>,
+   * which will cause the next call of {@link #display()} on the exclusive thread to
+   * release the {@link GLContext}. Only after it's async release, {@link #getExclusiveContextThread()}
+   * will return <code>null</code>.
+   * </p>
+   * <p>
+   * To release a previous made exclusive thread, a user issues <code>setExclusiveContextThread(null)</code>
+   * and may poll {@link #getExclusiveContextThread()} until it returns <code>null</code>,
+   * <i>while</i> the exclusive thread is still running.
+   * </p>
+   * <p>
+   * Note: Setting a new exclusive thread without properly releasing a previous one
+   * will throw an GLException.
+   * </p>
+   * <p>
+   * One scenario could be to dedicate the context to the {@link com.jogamp.opengl.util.AnimatorBase#getThread() animator thread}
+   * and spare redundant context switches.
+   * </p>
+   * @param t the exclusive thread to claim the context, or <code>null</code> for default operation.
+   * @return previous exclusive context thread
+   * @throws GLException If an exclusive thread is still active but a new one is attempted to be set
    */
-  public final void setSkipContextReleaseThread(Thread t) {
-    skipContextReleaseThread = t;
+  public final Thread setExclusiveContextThread(Thread t, GLContext context) throws GLException {
+    if (DEBUG) {
+      System.err.println("GLDrawableHelper.setExclusiveContextThread(): START switch "+getExclusiveContextSwitchString()+", thread "+exclusiveContextThread+" -> "+t+" -- currentThread "+Thread.currentThread());
+    }
+    final Thread oldExclusiveContextThread = exclusiveContextThread;
+    if( exclusiveContextThread == t ) {
+        exclusiveContextSwitch =  0; // keep
+    } else if( null == t ) {
+        exclusiveContextSwitch = -1; // release
+    } else {
+        exclusiveContextSwitch =  1; // claim
+        if( null != exclusiveContextThread ) {
+            throw new GLException("Release current exclusive Context Thread "+exclusiveContextThread+" first");
+        }
+        if( null != context && context.isCurrent() ) {
+            try {
+                forceNativeRelease(context);
+            } catch (Throwable ex) {
+                ex.printStackTrace();
+                throw new GLException(ex);
+            }
+        }
+        exclusiveContextThread = t;
+    }
+    if (DEBUG) {
+      System.err.println("GLDrawableHelper.setExclusiveContextThread(): END switch "+getExclusiveContextSwitchString()+", thread "+exclusiveContextThread+" -- currentThread "+Thread.currentThread());
+    }
+    return oldExclusiveContextThread;
   }
 
   /**
-   * @deprecated see {@link #setSkipContextReleaseThread(Thread)} 
+   * @see #setExclusiveContextThread(Thread, GLContext)
    */
-  public final Thread getSkipContextReleaseThread() {
-    return skipContextReleaseThread;
+  public final Thread getExclusiveContextThread() {
+    return exclusiveContextThread;
   }
-  
+
   private static final ThreadLocal<Runnable> perThreadInitAction = new ThreadLocal<Runnable>();
 
   /** Principal helper method which runs a Runnable with the context
@@ -346,104 +976,76 @@ public class GLDrawableHelper {
    * @param runnable
    * @param initAction
    */
-  public final void invokeGL(GLDrawable drawable,
-                             GLContext context,
-                             Runnable  runnable,
-                             Runnable  initAction) {
+  public final void invokeGL(final GLDrawable drawable,
+                             final GLContext context,
+                             final Runnable  runnable,
+                             final Runnable  initAction) {
     if(null==context) {
         if (DEBUG) {
-            Exception e = new GLException(Thread.currentThread().getName()+" Info: GLDrawableHelper " + this + ".invokeGL(): NULL GLContext");
+            Exception e = new GLException(getThreadName()+" Info: GLDrawableHelper " + this + ".invokeGL(): NULL GLContext");
             e.printStackTrace();
         }
         return;
     }
 
     if(PERF_STATS) {
-        invokeGLImplStats(drawable, context, runnable, initAction, null);    
+        invokeGLImplStats(drawable, context, runnable, initAction);
     } else {
-        invokeGLImpl(drawable, context, runnable, initAction, null);
+        invokeGLImpl(drawable, context, runnable, initAction);
     }
   }
 
-  /** 
-   * Principal helper method which runs {@link #dispose(GLAutoDrawable)} with the context
-   * made current and destroys the context afterwards while holding the lock.  
-   * 
+  /**
+   * Principal helper method which runs
+   * {@link #disposeAllGLEventListener(GLAutoDrawable, boolean) disposeAllGLEventListener(autoDrawable, false)}
+   * with the context made current.
+   * <p>
+   * If <code>destroyContext</code> is <code>true</code> the context is destroyed in the end while holding the lock.
+   * </p>
+   * <p>
+   * If <code>destroyContext</code> is <code>false</code> the context is natively released, i.e. released as often as locked before.
+   * </p>
    * @param autoDrawable
-   * @param drawable
    * @param context
-   * @param postAction
+   * @param destroyContext destroy context in the end while holding the lock
    */
-  public final void disposeGL(GLAutoDrawable autoDrawable,
-                              GLDrawable drawable,
-                              GLContext context,
-                              Runnable  postAction) {
-    if(PERF_STATS) {
-        invokeGLImplStats(drawable, context, null, null, autoDrawable);    
-    } else {
-        invokeGLImpl(drawable, context, null, null, autoDrawable);
-    }
-    if(null != postAction) {
-        postAction.run();
-    }
-  }
-  
-  private final void invokeGLImpl(GLDrawable drawable,
-                                  GLContext context,
-                                  Runnable  runnable,
-                                  Runnable  initAction,
-                                  GLAutoDrawable disposeAutoDrawable) {
-    final Thread currentThread = Thread.currentThread();
-    
-    final boolean isDisposeAction = null==initAction ;
-        
+  public final void disposeGL(final GLAutoDrawable autoDrawable,
+                              final GLContext context, boolean destroyContext) {
     // Support for recursive makeCurrent() calls as well as calling
     // other drawables' display() methods from within another one's
     GLContext lastContext = GLContext.getCurrent();
     Runnable  lastInitAction = null;
     if (lastContext != null) {
         if (lastContext == context) {
-            lastContext = null; // utilize recursive locking
+            lastContext = null;
         } else {
+            // utilize recursive locking
             lastInitAction = perThreadInitAction.get();
             lastContext.release();
         }
     }
-    int res = GLContext.CONTEXT_NOT_CURRENT;
-  
+
+    int res;
     try {
       res = context.makeCurrent();
-      if (res != GLContext.CONTEXT_NOT_CURRENT) {
-        if(!isDisposeAction) {
-            perThreadInitAction.set(initAction);
-            if (res == GLContext.CONTEXT_CURRENT_NEW) {
-              if (DEBUG) {
-                System.err.println("GLDrawableHelper " + this + ".invokeGL(): Running initAction");
-              }
-              initAction.run();
-            }
-            runnable.run();
-            if (autoSwapBufferMode) {
-                drawable.swapBuffers();
-            }
-        } else {
-            if(res == GLContext.CONTEXT_CURRENT_NEW) {
-                throw new GLException(currentThread.getName()+" GLDrawableHelper " + this + ".invokeGL(): Dispose case (no init action given): Native context was not created (new ctx): "+context);
-            }
-            if(listeners.size()>0) {
-                dispose(disposeAutoDrawable);
-            }
+      if (GLContext.CONTEXT_NOT_CURRENT != res) {
+        if(GLContext.CONTEXT_CURRENT_NEW == res) {
+            throw new GLException(getThreadName()+" GLDrawableHelper " + this + ".invokeGL(): Dispose case (no init action given): Native context was not created (new ctx): "+context);
+        }
+        if( listeners.size() > 0 && null != autoDrawable ) {
+            disposeAllGLEventListener(autoDrawable, false);
         }
       }
     } finally {
       try {
-          if(isDisposeAction) {
+          if(destroyContext) {
               context.destroy();
-          } else if( res != GLContext.CONTEXT_NOT_CURRENT ) {
-              context.release();
+          } else {
+              forceNativeRelease(context);
           }
+          flushGLRunnables();
       } catch (Exception e) {
-          System.err.println("Catched: "+e.getMessage());
+          System.err.println("Catched Exception on thread "+getThreadName());
           e.printStackTrace();
       }
       if (lastContext != null) {
@@ -454,99 +1056,206 @@ public class GLDrawableHelper {
       }
     }
   }
-  
-  private final void invokeGLImplStats(GLDrawable drawable,
-                                       GLContext context,
-                                       Runnable  runnable,
-                                       Runnable  initAction,
-                                       GLAutoDrawable disposeAutoDrawable) {
-    final Thread currentThread = Thread.currentThread();
-    
-    final boolean isDisposeAction = null==initAction ;
-    
-    // Support for recursive makeCurrent() calls as well as calling
-    // other drawables' display() methods from within another one's
-    int res = GLContext.CONTEXT_NOT_CURRENT;
-    GLContext lastContext = GLContext.getCurrent();
-    Runnable  lastInitAction = null;
-    if (lastContext != null) {
-        if (lastContext == context) {
-            if( currentThread == skipContextReleaseThread ) {
-                res = GLContext.CONTEXT_CURRENT;
-            } // else: utilize recursive locking
-            lastContext = null;
-        } else {
-            lastInitAction = perThreadInitAction.get();
-            lastContext.release();
-        }
-    }
-  
-    long t0 = System.currentTimeMillis();
-    long tdA = 0; // makeCurrent
-    long tdR = 0; // render time
-    long tdS = 0; // swapBuffers
-    long tdX = 0; // release
-    boolean ctxClaimed = false;
-    boolean ctxReleased = false;
-    boolean ctxDestroyed = false;    
-    try {
-      if (res == GLContext.CONTEXT_NOT_CURRENT) {
-          res = context.makeCurrent();
-          ctxClaimed = true;
-      }
-      if (res != GLContext.CONTEXT_NOT_CURRENT) {
-        if(!isDisposeAction) {
-            perThreadInitAction.set(initAction);
-            if (res == GLContext.CONTEXT_CURRENT_NEW) {
-              if (DEBUG) {
-                System.err.println("GLDrawableHelper " + this + ".invokeGL(): Running initAction");
-              }
-              initAction.run();
-            }
-            tdR = System.currentTimeMillis();        
-            tdA = tdR - t0; // makeCurrent
-            runnable.run();
-            tdS = System.currentTimeMillis();
-            tdR = tdS - tdR; // render time
-            if (autoSwapBufferMode) {
-                drawable.swapBuffers();
-                tdX = System.currentTimeMillis();
-                tdS = tdX - tdS; // swapBuffers
-            }
-        } else {
-            if(res == GLContext.CONTEXT_CURRENT_NEW) {
-                throw new GLException(currentThread.getName()+" GLDrawableHelper " + this + ".invokeGL(): Dispose case (no init action given): Native context was not created (new ctx): "+context);
-            }
-            if(listeners.size()>0) {
-                dispose(disposeAutoDrawable);
-            }
-        }
+
+  private final void invokeGLImpl(final GLDrawable drawable,
+          final GLContext context,
+          final Runnable  runnable,
+          final Runnable  initAction) {
+      final Thread currentThread = Thread.currentThread();
+
+      // Exclusive Cases:
+      //   1: lock - unlock  : default
+      //   2: lock - -       : exclusive,    not locked yet
+      //   3: -    - -       : exclusive,    already locked
+      //   4: -    - unlock  : ex-exclusive, already locked
+      final boolean _isExclusiveThread, _releaseExclusiveThread;
+      if( null != exclusiveContextThread) {
+          if( currentThread == exclusiveContextThread ) {
+              _releaseExclusiveThread = 0 > exclusiveContextSwitch;
+              _isExclusiveThread = !_releaseExclusiveThread;
+              exclusiveContextSwitch = 0;
+          } else {
+              // Exclusive thread usage, but on other thread
+              return;
+          }
+      } else {
+          _releaseExclusiveThread = false;
+          _isExclusiveThread = false;
       }
-    } finally {
+
+      // Support for recursive makeCurrent() calls as well as calling
+      // other drawables' display() methods from within another one's
+      int res = GLContext.CONTEXT_NOT_CURRENT;
+      GLContext lastContext = GLContext.getCurrent();
+      Runnable  lastInitAction = null;
+      if (lastContext != null) {
+          if (lastContext == context) {
+              res = GLContext.CONTEXT_CURRENT;
+              lastContext = null;
+          } else {
+              // utilize recursive locking
+              lastInitAction = perThreadInitAction.get();
+              lastContext.release();
+          }
+      }
+
       try {
-          if(isDisposeAction) {
-              context.destroy();
-              ctxDestroyed = true;
-          } else if( res != GLContext.CONTEXT_NOT_CURRENT &&
-                     (null == skipContextReleaseThread || currentThread != skipContextReleaseThread) ) {
-              context.release();
-              ctxReleased = true;
+          final boolean releaseContext;
+          if( GLContext.CONTEXT_NOT_CURRENT == res ) {
+              res = context.makeCurrent();
+              releaseContext = !_isExclusiveThread;
+          } else {
+              releaseContext = _releaseExclusiveThread;
+          }
+          if (GLContext.CONTEXT_NOT_CURRENT != res) {
+              try {
+                  perThreadInitAction.set(initAction);
+                  if (GLContext.CONTEXT_CURRENT_NEW == res) {
+                      if (DEBUG) {
+                          System.err.println("GLDrawableHelper " + this + ".invokeGL(): Running initAction");
+                      }
+                      initAction.run();
+                  }
+                  runnable.run();
+                  if ( autoSwapBufferMode ) {
+                      drawable.swapBuffers();
+                  }
+              } finally {
+                  if( _releaseExclusiveThread ) {
+                      exclusiveContextThread = null;
+                      if (DEBUG) {
+                          System.err.println("GLDrawableHelper.invokeGL() - Release ExclusiveContextThread -- currentThread "+Thread.currentThread());
+                      }
+                  }
+                  if( releaseContext ) {
+                      try {
+                          context.release();
+                      } catch (Exception e) {
+                          System.err.println("Catched Exception on thread "+getThreadName());
+                          e.printStackTrace();
+                      }
+                  }
+              }
+          }
+      } finally {
+          if (lastContext != null) {
+              final int res2 = lastContext.makeCurrent();
+              if (null != lastInitAction && res2 == GLContext.CONTEXT_CURRENT_NEW) {
+                  lastInitAction.run();
+              }
           }
-      } catch (Exception e) {
-          System.err.println("Catched: "+e.getMessage());
-          e.printStackTrace();
+      }
+  }
+
+  private final void invokeGLImplStats(final GLDrawable drawable,
+          final GLContext context,
+          final Runnable  runnable,
+          final Runnable  initAction) {
+      final Thread currentThread = Thread.currentThread();
+
+      // Exclusive Cases:
+      //   1: lock - unlock  : default
+      //   2: lock - -       : exclusive, not locked yet
+      //   3: -    - -       : exclusive, already locked
+      //   4: -    - unlock  : ex-exclusive, already locked
+      final boolean _isExclusiveThread, _releaseExclusiveThread;
+      if( null != exclusiveContextThread) {
+          if( currentThread == exclusiveContextThread ) {
+              _releaseExclusiveThread = 0 > exclusiveContextSwitch;
+              _isExclusiveThread = !_releaseExclusiveThread;
+          } else {
+              // Exclusive thread usage, but on other thread
+              return;
+          }
+      } else {
+          _releaseExclusiveThread = false;
+          _isExclusiveThread = false;
       }
 
-      tdX = System.currentTimeMillis() - tdX; // release / destroy
+      // Support for recursive makeCurrent() calls as well as calling
+      // other drawables' display() methods from within another one's
+      int res = GLContext.CONTEXT_NOT_CURRENT;
+      GLContext lastContext = GLContext.getCurrent();
+      Runnable  lastInitAction = null;
       if (lastContext != null) {
-        final int res2 = lastContext.makeCurrent();
-        if (null != lastInitAction && res2 == GLContext.CONTEXT_CURRENT_NEW) {
-          lastInitAction.run();
-        }
+          if (lastContext == context) {
+              res = GLContext.CONTEXT_CURRENT;
+              lastContext = null;
+          } else {
+              // utilize recursive locking
+              lastInitAction = perThreadInitAction.get();
+              lastContext.release();
+          }
       }
-    }
-    long td = System.currentTimeMillis() - t0;
-    System.err.println("td0 "+td+"ms, fps "+(1.0/(td/1000.0))+", td-makeCurrent: "+tdA+"ms, td-render "+tdR+"ms, td-swap "+tdS+"ms, td-release "+tdX+"ms, ctx claimed: "+ctxClaimed+", ctx release: "+ctxReleased+", ctx destroyed "+ctxDestroyed);
+
+      long t0 = System.currentTimeMillis();
+      long tdA = 0; // makeCurrent
+      long tdR = 0; // render time
+      long tdS = 0; // swapBuffers
+      long tdX = 0; // release
+      boolean ctxClaimed = false;
+      boolean ctxReleased = false;
+      boolean ctxDestroyed = false;
+      try {
+          final boolean releaseContext;
+          if( GLContext.CONTEXT_NOT_CURRENT == res ) {
+              res = context.makeCurrent();
+              releaseContext = !_isExclusiveThread;
+              ctxClaimed = true;
+          } else {
+              releaseContext = _releaseExclusiveThread;
+          }
+          if (GLContext.CONTEXT_NOT_CURRENT != res) {
+              try {
+                  perThreadInitAction.set(initAction);
+                  if (GLContext.CONTEXT_CURRENT_NEW == res) {
+                      if (DEBUG) {
+                          System.err.println("GLDrawableHelper " + this + ".invokeGL(): Running initAction");
+                      }
+                      initAction.run();
+                  }
+                  tdR = System.currentTimeMillis();
+                  tdA = tdR - t0; // makeCurrent
+                  runnable.run();
+                  tdS = System.currentTimeMillis();
+                  tdR = tdS - tdR; // render time
+                  if ( autoSwapBufferMode ) {
+                      drawable.swapBuffers();
+                      tdX = System.currentTimeMillis();
+                      tdS = tdX - tdS; // swapBuffers
+                  }
+              } finally {
+                  if( _releaseExclusiveThread ) {
+                      exclusiveContextSwitch = 0;
+                      exclusiveContextThread = null;
+                      if (DEBUG) {
+                          System.err.println("GLDrawableHelper.invokeGL() - Release ExclusiveContextThread -- currentThread "+Thread.currentThread());
+                      }
+                  }
+                  if( releaseContext ) {
+                      try {
+                          context.release();
+                          ctxReleased = true;
+                      } catch (Exception e) {
+                          System.err.println("Catched Exception on thread "+getThreadName());
+                          e.printStackTrace();
+                      }
+                  }
+              }
+          }
+      } finally {
+          tdX = System.currentTimeMillis() - tdX; // release / destroy
+          if (lastContext != null) {
+              final int res2 = lastContext.makeCurrent();
+              if (null != lastInitAction && res2 == GLContext.CONTEXT_CURRENT_NEW) {
+                  lastInitAction.run();
+              }
+          }
+      }
+      long td = System.currentTimeMillis() - t0;
+      System.err.println("td0 "+td+"ms, fps "+(1.0/(td/1000.0))+", td-makeCurrent: "+tdA+"ms, td-render "+tdR+"ms, td-swap "+tdS+"ms, td-release "+tdX+"ms, ctx claimed: "+ctxClaimed+", ctx release: "+ctxReleased+", ctx destroyed "+ctxDestroyed);
   }
-    
+
+  protected static String getThreadName() { return Thread.currentThread().getName(); }
+
 }