3 files changed, 29 insertions, 15 deletions
diff --git a/src/jogl/classes/javax/media/opengl/GLRunnable.java b/src/jogl/classes/javax/media/opengl/GLRunnable.java
index de0f5df48..cbd086c77 100644
--- a/src/jogl/classes/javax/media/opengl/GLRunnable.java
+++ b/src/jogl/classes/javax/media/opengl/GLRunnable.java
@@ -41,7 +41,11 @@ public interface GLRunnable {
     /**
      * Called by the drawable to initiate one-shot OpenGL commands by the
      * client, like {@link GLEventListener#display(GLAutoDrawable)}.
+     * 
+     * @param drawable the associated drawable the implementation shall use
+     * @return false if impl invalidates the back buffers, hence {@link GLAutoDrawable#display()} will 
+     *         issue another {@link GLEventListener#display(GLAutoDrawable)} call. Otherwise true.
      */
-    void run(GLAutoDrawable drawable);
+    boolean run(GLAutoDrawable drawable);
 }
 
diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
index 887e571cc..9353479ab 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
@@ -156,16 +156,21 @@ public class GLDrawableHelper {
   }
 
   public final void display(GLAutoDrawable drawable) {
-    synchronized(listenersLock) {
-        for (int i=0; i < listeners.size(); 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 ) ; 
-          listener.display(drawable);
-        }
+    displayImpl(drawable);
+    if(!execGLRunnables(drawable)) {
+        displayImpl(drawable);  
     }
-    execGLRunnables(drawable);
+  }
+  private 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, 
+            // in case this one is added after the realization of the GLAutoDrawable
+            init( listener, drawable, true ) ; 
+            listener.display(drawable);
+          }
+      }
   }
 
   private void reshape(GLEventListener listener, GLAutoDrawable drawable,
@@ -184,7 +189,8 @@ public class GLDrawableHelper {
     }
   }
 
-  private void execGLRunnables(GLAutoDrawable drawable) {
+  private boolean execGLRunnables(GLAutoDrawable drawable) {
+    boolean res = true;
     if(glRunnables.size()>0) {
         // swap one-shot list asap
         ArrayList<GLRunnable> _glRunnables = null;
@@ -194,12 +200,14 @@ public class GLDrawableHelper {
                 glRunnables = new ArrayList<GLRunnable>();
             }
         }
+        
         if(null!=_glRunnables) {
             for (int i=0; i < _glRunnables.size(); i++) {
-              _glRunnables.get(i).run(drawable);
+              res = _glRunnables.get(i).run(drawable) && res;
             }
         }
     }
+    return res;
   }
 
   public final void setAnimator(GLAnimatorControl animator) throws GLException {
diff --git a/src/jogl/classes/jogamp/opengl/GLRunnableTask.java b/src/jogl/classes/jogamp/opengl/GLRunnableTask.java
index e5b66b985..448f68423 100644
--- a/src/jogl/classes/jogamp/opengl/GLRunnableTask.java
+++ b/src/jogl/classes/jogamp/opengl/GLRunnableTask.java
@@ -50,10 +50,11 @@ public class GLRunnableTask implements GLRunnable {
         isExecuted = false;
     }
 
-    public void run(GLAutoDrawable drawable) {
+    public boolean run(GLAutoDrawable drawable) {
+        boolean res = true;
         if(null == notifyObject) {
             try {
-                runnable.run(drawable);
+                res = runnable.run(drawable);
             } catch (Throwable t) {
                 runnableException = t;
                 if(catchExceptions) {
@@ -67,7 +68,7 @@ public class GLRunnableTask implements GLRunnable {
         } else {
             synchronized (notifyObject) {
                 try {
-                    runnable.run(drawable);
+                    res = runnable.run(drawable);
                 } catch (Throwable t) {
                     runnableException = t;
                     if(catchExceptions) {
@@ -81,6 +82,7 @@ public class GLRunnableTask implements GLRunnable {
                 }
             }
         }
+        return res;
     }
 
     public boolean isExecuted() { return isExecuted; }