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)

1 files changed, 7 insertions, 2 deletions

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();
+  
 }