Bug 975 - GLJPanel's OffscreenDrawable shall not double swap (custom swap by GLEventListener using [AWT]GLReadBufferUtil)

When utilizing [AWT]GLReadBufferUtil it is usually desired to read from the front-buffer
instead the back-buffer. The latter may not be defined, e.g. when using MSAA.

A GLEventListener utilizing [AWT]GLReadBufferUtil,
must perform the drawable.swapBuffers() to be able to read from the front-buffer.

Usually GLAutoDrawable.setAutoSwapBuffer(false) should be called here,
to avoid a double swap - however GLJPanel does not support toggling auto-swap
since it requires to control swap for it's own read-pixels.

Remedy for GLJPanel:
  - GLJPanel issues helper.setAutoSwapBufferMode(false) - immutable

  - Enable GLJPanel.swapBuffer() if initializes
    This was previously disabled.

  - GLJPanel's OffscreenBackend listens to  surfaceUpdated,
    to be notified whether postGL needs to swap buffer
    or the drawable.swapBuffer() was already called between preGL and postGL.

See unit tests adding/removing a snapshot GLEventListener
performing swapBuffers() and setting auto-swap accordingly.

4 files changed, 350 insertions, 61 deletions

diff --git a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
index 522585f16..66a757d10 100644
--- a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
+++ b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
@@ -60,6 +60,7 @@ import java.util.List;
 
 import javax.media.nativewindow.AbstractGraphicsDevice;
 import javax.media.nativewindow.NativeSurface;
+import javax.media.nativewindow.SurfaceUpdatedListener;
 import javax.media.nativewindow.WindowClosingProtocol;
 import javax.media.opengl.GL;
 import javax.media.opengl.GL2;
@@ -222,7 +223,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
       return singleAWTGLPixelBufferProvider;
   }
 
-  private final GLDrawableHelper helper = new GLDrawableHelper();
+  private final GLDrawableHelper helper;
   private volatile boolean isInitialized;
 
   //
@@ -352,9 +353,13 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
     this.glProfile = offscreenCaps.getGLProfile();
     this.factory = GLDrawableFactoryImpl.getFactoryImpl(glProfile);
     this.chooser = chooser;
+
+    helper = new GLDrawableHelper();
+    helper.setAutoSwapBufferMode(false); /** Always handles buffer swapping in Backend! */
     if( null != shareWith ) {
         helper.setSharedContext(null, shareWith);
     }
+
     this.setFocusable(true); // allow keyboard input!
     this.addHierarchyListener(hierarchyListener);
     this.isShowing = isShowing();
@@ -941,34 +946,25 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
 
   @Override
   public void setAutoSwapBufferMode(boolean onOrOff) {
-    // In the current implementation this is a no-op. Both the pbuffer
-    // and pixmap based rendering paths use a single-buffered surface
-    // so swapping the buffers doesn't do anything. We also don't
-    // currently have the provision to skip copying the data to the
-    // Swing portion of the GLJPanel in any of the rendering paths.
+    // In the current implementation this is a no-op.
+    // All Backend's require control of buffer swapping,
+    // i.e. as required for MSAA offscreen FBO buffer.
   }
 
   @Override
   public boolean getAutoSwapBufferMode() {
-    // In the current implementation this is a no-op. Both the pbuffer
-    // and pixmap based rendering paths use a single-buffered surface
-    // so swapping the buffers doesn't do anything. We also don't
-    // currently have the provision to skip copying the data to the
-    // Swing portion of the GLJPanel in any of the rendering paths.
+    // In the current implementation this is a no-op.
+    // All Backend's require control of buffer swapping,
+    // i.e. as required for MSAA offscreen FBO buffer.
     return true;
   }
 
   @Override
   public void swapBuffers() {
-    // In the current implementation this is a no-op. Both the pbuffer
-    // and pixmap based rendering paths use a single-buffered surface
-    // so swapping the buffers doesn't do anything. We also don't
-    // currently have the provision to skip copying the data to the
-    // Swing portion of the GLJPanel in any of the rendering paths.
-    if( printActive && isInitialized) {
+    if( isInitialized ) {
         final Backend b = backend;
         if ( null != b ) {
-            b.getDrawable().swapBuffers();
+            b.swapBuffers();
         }
     }
   }
@@ -1366,6 +1362,11 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
     public boolean preGL(Graphics g);
 
     /**
+     * Shall invoke underlying drawable's swapBuffer.
+     */
+    public void swapBuffers();
+
+    /**
      * Called after the OpenGL work is done in init() and display().
      * The isDisplay argument indicates whether this was called on
      * behalf of a call to display() rather than init().
@@ -1401,6 +1402,8 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
     private volatile GLContextImpl offscreenContext; // volatile: avoid locking for read-only access
     private boolean flipVertical;
 
+    private boolean needsSwapBuffers = true;
+
     // For saving/restoring of OpenGL state during ReadPixels
     private final GLPixelStorageModes psm =  new GLPixelStorageModes();
 
@@ -1436,6 +1439,12 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
                                                     chooser,
                                                     panelWidth, panelHeight);
           offscreenDrawable.setRealized(true);
+          offscreenDrawable.getNativeSurface().addSurfaceUpdatedListener(new SurfaceUpdatedListener() {
+              @Override
+              public final void surfaceUpdated(Object updater, NativeSurface ns, long when) {
+                  needsSwapBuffers = false;
+              } } );
+
           offscreenContext = (GLContextImpl) offscreenDrawable.createContext(shareWith[0]);
           offscreenContext.setContextCreationFlags(additionalCtxCreationFlags);
           if( GLContext.CONTEXT_NOT_CURRENT < offscreenContext.makeCurrent() ) {
@@ -1453,8 +1462,6 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
                           ", isGL2ES2 " + gl.isGL2ES2()+"]");
               }
               if( useGLSLFlip ) {
-                  final boolean _autoSwapBufferMode = helper.getAutoSwapBufferMode();
-                  helper.setAutoSwapBufferMode(false);
                   final GLFBODrawable fboDrawable = (GLFBODrawable) offscreenDrawable;
                   fboDrawable.setTextureUnit( GLJPanel.this.requestedTextureUnit );
                   try {
@@ -1475,7 +1482,6 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
                         fboFlipped.destroy(gl);
                         fboFlipped = null;
                       }
-                      helper.setAutoSwapBufferMode(_autoSwapBufferMode);
                   }
               } else {
                   fboFlipped = null;
@@ -1558,11 +1564,19 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
 
     @Override
     public final boolean preGL(Graphics g) {
-      // Empty in this implementation
+      needsSwapBuffers = true;
       return true;
     }
 
     @Override
+    public final void swapBuffers() {
+        final GLDrawable d = offscreenDrawable;
+        if( null != d ) {
+            d.swapBuffers();
+        }
+    }
+
+    @Override
     public final void postGL(Graphics g, boolean isDisplay) {
       if (isDisplay) {
         final GL gl = offscreenContext.getGL();
@@ -1652,7 +1666,9 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
             gl2es3.glReadBuffer(gl2es3.getDefaultReadBuffer());
         }
 
-        offscreenDrawable.swapBuffers();
+        if( needsSwapBuffers ) {
+            offscreenDrawable.swapBuffers();
+        }
 
         if(null != glslTextureRaster) { // implies flippedVertical
             final boolean viewportChange;
@@ -1924,13 +1940,13 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
 
     @Override
     public final GLCapabilitiesImmutable getChosenGLCapabilities() {
-      // FIXME: should do better than this; is it possible to using only platform-independent code?
+      // FIXME: should do better than this; is it possible to query J2D Caps ?
       return new GLCapabilities(null);
     }
 
     @Override
     public final GLProfile getGLProfile() {
-      // FIXME: should do better than this; is it possible to using only platform-independent code?
+      // FIXME: should do better than this; is it possible to query J2D's Profile ?
       return GLProfile.getDefault(GLProfile.getDefaultDevice());
     }
 
@@ -2078,6 +2094,14 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable, WindowClosing
     }
 
     @Override
+    public final void swapBuffers() {
+        final GLDrawable d = joglDrawable;
+        if( null != d ) {
+            d.swapBuffers();
+        }
+    }
+
+    @Override
     public final void postGL(Graphics g, boolean isDisplay) {
       // Cause OpenGL pipeline to flush its results because
       // otherwise it's possible we will buffer up multiple frames'
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/acore/GLReadBuffer00Base.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/GLReadBuffer00Base.java
new file mode 100644
index 000000000..c5885d6b4
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/GLReadBuffer00Base.java
@@ -0,0 +1,97 @@
+/**
+ * Copyright 2014 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 java.lang.reflect.InvocationTargetException;
+
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLProfile;
+
+import org.junit.BeforeClass;
+import org.junit.FixMethodOrder;
+import org.junit.Test;
+import org.junit.runners.MethodSorters;
+
+import com.jogamp.opengl.test.junit.util.UITestCase;
+
+/**
+ * Multiple GLJPanels in a JFrame
+ */
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public abstract class GLReadBuffer00Base extends UITestCase {
+
+    @BeforeClass
+    public static void initClass() {
+        GLProfile.initSingleton();
+    }
+
+    protected abstract void test(final GLCapabilitiesImmutable caps, final boolean useSwingDoubleBuffer, final boolean skipGLOrientationVerticalFlip);
+
+    private boolean defAutoSwapBufferMode = true;
+    protected void addSnapshotGLEL(final GLAutoDrawable glad, final GLEventListener snapshotGLEL) {
+        defAutoSwapBufferMode = glad.getAutoSwapBufferMode();
+        glad.setAutoSwapBufferMode(false);
+        glad.addGLEventListener(snapshotGLEL);
+    }
+    protected void removeSnapshotGLEL(final GLAutoDrawable glad, final GLEventListener snapshotGLEL) {
+        glad.removeGLEventListener(snapshotGLEL);
+        glad.setAutoSwapBufferMode(defAutoSwapBufferMode);
+    }
+
+
+    @Test
+    public void test00_MSAA0_DefFlip() throws InterruptedException, InvocationTargetException {
+        test(new GLCapabilities(null), false /*useSwingDoubleBuffer*/, false /* skipGLOrientationVerticalFlip */);
+    }
+
+    @Test
+    public void test01_MSAA0_UsrFlip() throws InterruptedException, InvocationTargetException {
+        test(new GLCapabilities(null), false /*useSwingDoubleBuffer*/, true /* skipGLOrientationVerticalFlip */);
+    }
+
+    @Test
+    public void test10_MSAA4_DefFlip() throws InterruptedException, InvocationTargetException {
+        final GLCapabilities caps = new GLCapabilities(null);
+        caps.setNumSamples(4);
+        caps.setSampleBuffers(true);
+        test(caps, false /*useSwingDoubleBuffer*/, false /* skipGLOrientationVerticalFlip */);
+    }
+
+    @Test
+    public void test11_MSAA4_UsrFlip() throws InterruptedException, InvocationTargetException {
+        final GLCapabilities caps = new GLCapabilities(null);
+        caps.setNumSamples(4);
+        caps.setSampleBuffers(true);
+        test(caps, false /*useSwingDoubleBuffer*/, true /* skipGLOrientationVerticalFlip */);
+    }
+
+    static long duration = 500; // ms
+}
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/awt/TestGLJPanelResize02AWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestGLReadBuffer01GLJPanelAWT.java
index dabfb737a..4ad84aa73 100644
--- a/src/test/com/jogamp/opengl/test/junit/jogl/awt/TestGLJPanelResize02AWT.java
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestGLReadBuffer01GLJPanelAWT.java
@@ -25,19 +25,17 @@
  * authors and should not be interpreted as representing official policies, either expressed
  * or implied, of JogAmp Community.
  */
-package com.jogamp.opengl.test.junit.jogl.awt;
+package com.jogamp.opengl.test.junit.jogl.acore;
 
 import java.awt.BorderLayout;
 import java.awt.Dimension;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
 
 import javax.imageio.ImageIO;
 import javax.media.opengl.GL;
 import javax.media.opengl.GLAutoDrawable;
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLCapabilitiesImmutable;
 import javax.media.opengl.GLDrawable;
 import javax.media.opengl.GLEventListener;
@@ -50,12 +48,11 @@ import javax.swing.SwingUtilities;
 import org.junit.Assume;
 import org.junit.BeforeClass;
 import org.junit.FixMethodOrder;
-import org.junit.Test;
 import org.junit.runners.MethodSorters;
 
 import com.jogamp.opengl.test.junit.jogl.demos.es2.GearsES2;
 import com.jogamp.opengl.test.junit.util.MiscUtils;
-import com.jogamp.opengl.test.junit.util.UITestCase;
+import com.jogamp.opengl.util.Animator;
 import com.jogamp.opengl.util.awt.AWTGLReadBufferUtil;
 import com.jogamp.opengl.util.texture.TextureIO;
 
@@ -63,18 +60,18 @@ import com.jogamp.opengl.util.texture.TextureIO;
  * Multiple GLJPanels in a JFrame
  */
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
-public class TestGLJPanelResize02AWT extends UITestCase {
+public class TestGLReadBuffer01GLJPanelAWT extends GLReadBuffer00Base {
 
     @BeforeClass
     public static void initClass() {
         GLProfile.initSingleton();
     }
 
-    public void test(final GLCapabilitiesImmutable caps, final boolean useSwingDoubleBuffer) {
+    public void test(final GLCapabilitiesImmutable caps, final boolean useSwingDoubleBuffer, final boolean skipGLOrientationVerticalFlip) {
         final AWTGLReadBufferUtil awtGLReadBufferUtil = new AWTGLReadBufferUtil(caps.getGLProfile(), false);
         final JFrame frame = new JFrame();
         final Dimension d = new Dimension(320, 240);
-
+        final GLJPanel glad = createGLJPanel(skipGLOrientationVerticalFlip, useSwingDoubleBuffer, caps, d);
         try {
             javax.swing.SwingUtilities.invokeAndWait(new Runnable() {
                 public void run() {
@@ -84,11 +81,10 @@ public class TestGLJPanelResize02AWT extends UITestCase {
                     panel.setDoubleBuffered(useSwingDoubleBuffer);
                     frame.getContentPane().add(panel);
 
-                    final GLJPanel glad = createGLJPanel(useSwingDoubleBuffer, caps, d);
                     final GearsES2 gears = new GearsES2(0);
+                    gears.setFlipVerticalInGLOrientation(skipGLOrientationVerticalFlip);
                     gears.setVerbose(false);
                     glad.addGLEventListener(gears);
-                    glad.addGLEventListener(new SnapshotGLEL(awtGLReadBufferUtil));
                     panel.add(glad);
                     frame.pack();
                     frame.setVisible(true);
@@ -97,10 +93,18 @@ public class TestGLJPanelResize02AWT extends UITestCase {
             throwable.printStackTrace();
             Assume.assumeNoException( throwable );
         }
+        final GLEventListener snapshotGLEL = new SnapshotGLEL(awtGLReadBufferUtil, skipGLOrientationVerticalFlip);
         final Dimension size0 = frame.getSize();
-        final Dimension size1 = new Dimension(size0.width+30, size0.height+30);
-        final Dimension size2 = new Dimension(size0.width-30, size0.height-30);
+        final Dimension size1 = new Dimension(size0.width+100, size0.height+100);
+        final Dimension size2 = new Dimension(size0.width-100, size0.height-100);
         try {
+            final Animator anim = new Animator(glad);
+            anim.start();
+            try { Thread.sleep(2*duration); } catch (InterruptedException e) { }
+            anim.stop();
+            addSnapshotGLEL(glad, snapshotGLEL);
+            glad.display();
+
             try { Thread.sleep(duration); } catch (InterruptedException e) { }
             javax.swing.SwingUtilities.invokeAndWait(new Runnable() {
                     public void run() {
@@ -120,6 +124,11 @@ public class TestGLJPanelResize02AWT extends UITestCase {
                         frame.validate();
                     } } );
             try { Thread.sleep(duration); } catch (InterruptedException e) { }
+
+            removeSnapshotGLEL(glad, snapshotGLEL);
+            anim.start();
+            try { Thread.sleep(2*duration); } catch (InterruptedException e) { }
+            anim.stop();
         } catch (Exception e1) {
             e1.printStackTrace();
         }
@@ -133,12 +142,24 @@ public class TestGLJPanelResize02AWT extends UITestCase {
         }
     }
 
+    private GLJPanel createGLJPanel(final boolean skipGLOrientationVerticalFlip, final boolean useSwingDoubleBuffer, final GLCapabilitiesImmutable caps, final Dimension size) {
+        final GLJPanel canvas = new GLJPanel(caps);
+        canvas.setSize(size);
+        canvas.setPreferredSize(size);
+        canvas.setMinimumSize(size);
+        canvas.setDoubleBuffered(useSwingDoubleBuffer);
+        canvas.setSkipGLOrientationVerticalFlip(skipGLOrientationVerticalFlip);
+        return canvas;
+    }
+
     private class SnapshotGLEL implements GLEventListener {
         final AWTGLReadBufferUtil glReadBufferUtil;
+        final boolean skipGLOrientationVerticalFlip;
         int i;
 
-        SnapshotGLEL(final AWTGLReadBufferUtil glReadBufferUtil) {
+        SnapshotGLEL(final AWTGLReadBufferUtil glReadBufferUtil, final boolean skipGLOrientationVerticalFlip) {
             this.glReadBufferUtil = glReadBufferUtil;
+            this.skipGLOrientationVerticalFlip = skipGLOrientationVerticalFlip;
             i = 0;
         }
 
@@ -157,40 +178,29 @@ public class TestGLJPanelResize02AWT extends UITestCase {
             final String filenameAWT = getSnapshotFilename(sn, "awt",
                                                            drawable.getChosenGLCapabilities(), drawable.getWidth(), drawable.getHeight(),
                                                            glReadBufferUtil.hasAlpha(), fileSuffix, destPath);
-            final String filenameJGL = getSnapshotFilename(sn, "jgl",
-                                                           drawable.getChosenGLCapabilities(), drawable.getWidth(), drawable.getHeight(),
-                                                           glReadBufferUtil.hasAlpha(), fileSuffix, destPath);
-            System.err.println(Thread.currentThread().getName()+": ** screenshot: "+filenameAWT+", "+filenameJGL);
-            gl.glFinish(); // just make sure rendering finished ..
-            final BufferedImage image = glReadBufferUtil.readPixelsToBufferedImage(gl, true /* awtOrientation */);
+            // gl.glFinish(); // just make sure rendering finished ..
+            drawable.swapBuffers();
+            final boolean awtOrientation = !( drawable.isGLOriented() && skipGLOrientationVerticalFlip );
+            System.err.println(Thread.currentThread().getName()+": ** screenshot: awtOrient/v-flip "+awtOrientation+", "+filenameAWT);
+
+            final BufferedImage image = glReadBufferUtil.readPixelsToBufferedImage(gl, awtOrientation);
             final File fout = new File(filenameAWT);
             try {
                 ImageIO.write(image, "png", fout);
             } catch (IOException e) {
                 e.printStackTrace();
             }
+            /**
+            final String filenameJGL = getSnapshotFilename(sn, "jgl",
+                                                           drawable.getChosenGLCapabilities(), drawable.getWidth(), drawable.getHeight(),
+                                                           glReadBufferUtil.hasAlpha(), fileSuffix, destPath);
             glReadBufferUtil.write(new File(filenameJGL));
+            */
         }
     };
 
-    private GLJPanel createGLJPanel(final boolean useSwingDoubleBuffer, final GLCapabilitiesImmutable caps, final Dimension size) {
-        final GLJPanel canvas = new GLJPanel(caps);
-        canvas.setSize(size);
-        canvas.setPreferredSize(size);
-        canvas.setMinimumSize(size);
-        canvas.setDoubleBuffered(useSwingDoubleBuffer);
-        return canvas;
-    }
-
     static GLCapabilitiesImmutable caps = null;
 
-    @Test
-    public void test00() throws InterruptedException, InvocationTargetException {
-        test(new GLCapabilities(null), false /*useSwingDoubleBuffer*/);
-    }
-
-    static long duration = 500; // ms
-
     public static void main(String[] args) {
         for(int i=0; i<args.length; i++) {
             if(args[i].equals("-time")) {
@@ -198,7 +208,7 @@ public class TestGLJPanelResize02AWT extends UITestCase {
                 duration = MiscUtils.atol(args[i], duration);
             }
         }
-        org.junit.runner.JUnitCore.main(TestGLJPanelResize02AWT.class.getName());
+        org.junit.runner.JUnitCore.main(TestGLReadBuffer01GLJPanelAWT.class.getName());
     }
 
 }
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestGLReadBuffer01GLWindowNEWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestGLReadBuffer01GLWindowNEWT.java
new file mode 100644
index 000000000..598ec1021
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/TestGLReadBuffer01GLWindowNEWT.java
@@ -0,0 +1,158 @@
+/**
+ * Copyright 2014 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 java.io.File;
+
+import javax.media.nativewindow.util.Dimension;
+import javax.media.nativewindow.util.DimensionImmutable;
+import javax.media.opengl.GL;
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLDrawable;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLProfile;
+
+import org.junit.Assume;
+import org.junit.BeforeClass;
+import org.junit.FixMethodOrder;
+import org.junit.runners.MethodSorters;
+
+import com.jogamp.newt.opengl.GLWindow;
+import com.jogamp.opengl.test.junit.jogl.demos.es2.GearsES2;
+import com.jogamp.opengl.test.junit.util.MiscUtils;
+import com.jogamp.opengl.util.Animator;
+import com.jogamp.opengl.util.GLReadBufferUtil;
+import com.jogamp.opengl.util.texture.TextureIO;
+
+/**
+ * Multiple GLJPanels in a JFrame
+ */
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class TestGLReadBuffer01GLWindowNEWT extends GLReadBuffer00Base {
+
+    @BeforeClass
+    public static void initClass() {
+        GLProfile.initSingleton();
+    }
+
+    public void test(final GLCapabilitiesImmutable caps, final boolean useSwingDoubleBuffer, final boolean skipGLOrientationVerticalFlip) {
+        if( skipGLOrientationVerticalFlip || useSwingDoubleBuffer ) {
+            return; // NOP
+        }
+        final GLReadBufferUtil glReadBufferUtil = new GLReadBufferUtil(false, false);
+        final GLWindow glad= GLWindow.create(caps);
+        try {
+            glad.setPosition(64, 64);
+            glad.setSize(320, 240);
+            final GearsES2 gears = new GearsES2(0);
+            gears.setVerbose(false);
+            glad.addGLEventListener(gears);
+            glad.setVisible(true);
+        } catch( Throwable throwable ) {
+            throwable.printStackTrace();
+            Assume.assumeNoException( throwable );
+        }
+        final GLEventListener snapshotGLEL = new SnapshotGLEL(glReadBufferUtil);
+        final DimensionImmutable size0 = new Dimension(glad.getWidth(), glad.getHeight());
+        final DimensionImmutable size1 = new Dimension(size0.getWidth()+100, size0.getHeight()+100);
+        final DimensionImmutable size2 = new Dimension(size0.getWidth()-100, size0.getHeight()-100);
+        try {
+            final Animator anim = new Animator(glad);
+            anim.start();
+            try { Thread.sleep(2*duration); } catch (InterruptedException e) { }
+            anim.stop();
+            addSnapshotGLEL(glad, snapshotGLEL);
+            glad.display();
+
+            try { Thread.sleep(duration); } catch (InterruptedException e) { }
+            glad.setSize(size1.getWidth(), size1.getHeight());
+            try { Thread.sleep(duration); } catch (InterruptedException e) { }
+            glad.setSize(size2.getWidth(), size2.getHeight());
+            try { Thread.sleep(duration); } catch (InterruptedException e) { }
+            glad.setSize(size0.getWidth(), size0.getHeight());
+            try { Thread.sleep(duration); } catch (InterruptedException e) { }
+
+            removeSnapshotGLEL(glad, snapshotGLEL);
+            anim.start();
+            try { Thread.sleep(2*duration); } catch (InterruptedException e) { }
+            anim.stop();
+        } catch (Exception e1) {
+            e1.printStackTrace();
+        }
+        glad.destroy();
+    }
+
+    private class SnapshotGLEL implements GLEventListener {
+        final GLReadBufferUtil glReadBufferUtil;
+        int i;
+
+        SnapshotGLEL(final GLReadBufferUtil glReadBufferUtil) {
+            this.glReadBufferUtil = glReadBufferUtil;
+            i = 0;
+        }
+
+        @Override
+        public void init(GLAutoDrawable drawable) { }
+        @Override
+        public void dispose(GLAutoDrawable drawable) { }
+        @Override
+        public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) { }
+        @Override
+        public void display(GLAutoDrawable drawable) {
+            snapshot(i++, drawable.getGL(), TextureIO.PNG, null);
+        }
+        public void snapshot(int sn, GL gl, String fileSuffix, String destPath) {
+            final GLDrawable drawable = gl.getContext().getGLReadDrawable();
+            final String filenameJGL = getSnapshotFilename(sn, "jgl",
+                                                           drawable.getChosenGLCapabilities(), drawable.getWidth(), drawable.getHeight(),
+                                                           glReadBufferUtil.hasAlpha(), fileSuffix, destPath);
+            // gl.glFinish(); // just make sure rendering finished ..
+            drawable.swapBuffers();
+            final boolean mustFlipVertically = !drawable.isGLOriented();
+            System.err.println(Thread.currentThread().getName()+": ** screenshot: v-flip "+mustFlipVertically+", "+filenameJGL);
+
+            if(glReadBufferUtil.readPixels(gl, mustFlipVertically)) {
+                glReadBufferUtil.write(new File(filenameJGL));
+            }
+        }
+    };
+
+    static GLCapabilitiesImmutable caps = null;
+
+    public static void main(String[] args) {
+        for(int i=0; i<args.length; i++) {
+            if(args[i].equals("-time")) {
+                i++;
+                duration = MiscUtils.atol(args[i], duration);
+            }
+        }
+        org.junit.runner.JUnitCore.main(TestGLReadBuffer01GLWindowNEWT.class.getName());
+    }
+
+}