Fix OSX OffscreenLayerSurface (OLS) regressions (pbuffer based)

- Use pbuffer (still), don't set FBO (invisible)

- OLS (only impl is JAWTWindow now) stores the attached layer handle
  created and attached by the GLContext implementation,
  so 'others' may detach it -> NewtCanvasAWT

- NewtCanvasAWT.removeNotify() needs to ask the OLS to detach the layer
  since it's parent will be gone.

- MacOSXCGLContext destroy allows a removed OLS (see above)

2 files changed, 22 insertions, 5 deletions

diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java b/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
index cffe495f7..d4b927cf1 100644
--- a/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
+++ b/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
@@ -81,6 +81,7 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
   protected long drawable;
   protected Rectangle bounds;
   protected Insets insets;
+  private long offscreenSurfaceLayer;
 
   private long drawable_old;
 
@@ -106,6 +107,7 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
     invalidate();
     this.component = windowObject;
     this.isApplet = false;
+    this.offscreenSurfaceLayer = 0;
   }
 
   @Override
@@ -196,6 +198,7 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
             System.err.println("JAWTWindow.attachSurfaceHandle(): 0x"+Long.toHexString(layerHandle) + ", bounds "+bounds);
           }
           attachSurfaceLayerImpl(layerHandle);
+          offscreenSurfaceLayer = layerHandle;
       } finally {
           unlockSurface();
       }
@@ -206,25 +209,34 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
    * {@inheritDoc}
    */
   @Override
-  public final void detachSurfaceLayer(final long layerHandle) throws NativeWindowException {
+  public final void detachSurfaceLayer() throws NativeWindowException {
       if( !isOffscreenLayerSurfaceEnabled() ) {
           throw new java.lang.UnsupportedOperationException("Not an offscreen layer surface");
       }
+      if( 0 == offscreenSurfaceLayer) {
+          throw new NativeWindowException("No offscreen layer attached: "+this);
+      }
       int lockRes = lockSurface();
       if (NativeSurface.LOCK_SURFACE_NOT_READY >= lockRes) {
           throw new NativeWindowException("Could not lock (offscreen layer): "+this);
       }
       try {
           if(DEBUG) {
-            System.err.println("JAWTWindow.detachSurfaceHandle(): 0x"+Long.toHexString(layerHandle));
+            System.err.println("JAWTWindow.detachSurfaceHandle(): 0x"+Long.toHexString(offscreenSurfaceLayer));
           }
-          detachSurfaceLayerImpl(layerHandle);
+          detachSurfaceLayerImpl(offscreenSurfaceLayer);
+          offscreenSurfaceLayer = 0;
       } finally {
           unlockSurface();
       }
   }
   protected abstract void detachSurfaceLayerImpl(final long layerHandle);
 
+  @Override
+  public final boolean isSurfaceLayerAttached() {
+      return 0 != offscreenSurfaceLayer;
+  }
+  
   //
   // SurfaceUpdateListener
   //
diff --git a/src/nativewindow/classes/javax/media/nativewindow/OffscreenLayerSurface.java b/src/nativewindow/classes/javax/media/nativewindow/OffscreenLayerSurface.java
index dd36509ba..f7dbc6c27 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/OffscreenLayerSurface.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/OffscreenLayerSurface.java
@@ -42,7 +42,12 @@ public interface OffscreenLayerSurface {
    * Detaches a previously attached offscreen layer from this offscreen layer surface.
    * @see #attachSurfaceLayer(long)
    * @see #isOffscreenLayerSurfaceEnabled()
-   * @throws NativeWindowException if {@link #isOffscreenLayerSurfaceEnabled()} == false
+   * @throws NativeWindowException if {@link #isOffscreenLayerSurfaceEnabled()} == false 
+   *                               or no surface layer is attached.
    */
-  public void detachSurfaceLayer(final long layerHandle) throws NativeWindowException;
+  public void detachSurfaceLayer() throws NativeWindowException;
+  
+  /** Returns true if a surface layer is attached, otherwise false. */
+  public boolean isSurfaceLayerAttached();
+  
 }