Bug 665 (part 1) - Allow dis-association of GLContext's GLDrawable ..

Changes allowing re-association (incl. null) of GLContext/GLDrawable:

- GLAutoDrawable: Refine API doc 'setContext(..)'

- GLContext: Refine API doc: 'setGLDrawable(..)' 'getGLDrawable()'

- GLContextImpl.setGLDrawable(): Handle null drawable

- GLAutoDrawableDelegate/GLAutoDrawableBase: Allow null GLContext

- GLDrawableHelper.switchContext(..)/recreateGLDrawable(): Balance GLContext.setGLDrawable(..) calls

- New GLEventListenerState, holding state vector [GLEventListener, GLContext, .. ]
  impl. relocation of all components from/to GLAutoDrawable.

- GLDrawableUtil
  - Using GLEventListenerState for swapGLContextAndAllGLEventListener(..)

+++

NEWT Window*:
  - getDisplayHandle() is 'final', no more 'shortcut' code allowed
    due to re-association incl. display handle.

  - close*:
    - close config's device (was missing)
    - null config

+++

Changes allowing reconfig of Display handle as required
to re-associate pre-existing GLContext to a 'window':

- AbstractGraphicsDevice: Add isHandleOwner() / clearHandleOwner()
  - Impl. in X11GraphicsDevice and EGLGraphicsDevice, NOP in DefaultGraphicsDevice

- DefaultGraphicsConfiguration add 'setScreen(..)'

- MutableGraphicsConfiguration
  - Make DefaultGraphicsConfiguration.setScreen(..) public

- NativeWindowFactory add 'createScreen(String type, AbstractGraphicsDevice device, int screen)'
  - Refactored from SWTAccessor

- NativeWindow x11ErrorHandler: Dump Stack Trace in DEBUG mode, always.

2 files changed, 32 insertions, 23 deletions

diff --git a/src/jogl/classes/javax/media/opengl/GLAutoDrawable.java b/src/jogl/classes/javax/media/opengl/GLAutoDrawable.java
index a7db3f3fd..612ff6bdb 100644
--- a/src/jogl/classes/javax/media/opengl/GLAutoDrawable.java
+++ b/src/jogl/classes/javax/media/opengl/GLAutoDrawable.java
@@ -130,37 +130,35 @@ public interface GLAutoDrawable extends GLDrawable {
   public GLContext getContext();
 
   /**
-   * Associate a new context to this drawable and also propagates the context/drawable switch by 
-   * calling {@link GLContext#setGLDrawable(GLDrawable, boolean) newCtx.setGLDrawable(drawable, true);}.
-   * <code>drawable</code> might be an inner GLDrawable instance if using a delegation pattern,
-   * or this GLAutoDrawable instance.
+   * Associate the new context, <code>newtCtx</code>, to this auto-drawable.
    * <p>
-   * If the old or new context was current on this thread, it is being released before switching the drawable.
+   * The current context will be dis-associated from this auto-drawable 
+   * via {@link GLContext#setGLDrawable(GLDrawable, boolean) setGLDrawable(null, true);} first.
+   * </p>
+   * <p>
+   * The new context will be associated with this auto-drawable 
+   * 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 association.
    * The new context will be made current afterwards, if it was current before. 
    * However the user shall take extra care that no other thread
    * attempts to make this context current.
    * </p>
    * <p>
-   * Be aware that the old context is still bound to the drawable, 
-   * and that one context can only be bound to one drawable at one time!
-   * </p>
-   * <p>
    * In case you do not intend to use the old context anymore, i.e. 
-   * not assigning it to another drawable, it shall be 
-   * destroyed before setting the new context, i.e.:
+   * not assigning it to another drawable, it shall be
+   * destroyed, i.e.:
    * <pre>
-            GLContext oldCtx = glad.getContext();
+            GLContext oldCtx = glad.setContext(newCtx);
             if(null != oldCtx) {
                 oldCtx.destroy();
             }
-            glad.setContext(newCtx);            
    * </pre> 
-   * This is required, since a context must have a valid drawable at all times
-   * and this API shall not restrict the user in any way. 
    * </p>
    * 
-   * @param newCtx the new context
-   * @return the replaced GLContext, maybe <code>null</code>
+   * @param newCtx the new context, maybe <code>null</code> for dis-association.
+   * @return the previous GLContext, maybe <code>null</code>
    *  
    * @see GLContext#setGLDrawable(GLDrawable, boolean)
    * @see GLContext#setGLReadDrawable(GLDrawable)
diff --git a/src/jogl/classes/javax/media/opengl/GLContext.java b/src/jogl/classes/javax/media/opengl/GLContext.java
index 455f2d70d..4817add4d 100644
--- a/src/jogl/classes/javax/media/opengl/GLContext.java
+++ b/src/jogl/classes/javax/media/opengl/GLContext.java
@@ -217,15 +217,20 @@ public abstract class GLContext {
   /**
    * Sets the read/write drawable for framebuffer operations.
    * <p>
+   * If the arguments reflect the current state of this context
+   * this method is a no-operation and returns the old and current {@link GLDrawable}.
+   * </p>
+   * <p>
    * If the context was current on this thread, it is being released before switching the drawable
    * and made current afterwards. However the user shall take extra care that not other thread
    * attempts to make this context current. Otherwise a race condition may happen.
    * </p>
-   * @param readWrite the read/write drawable for framebuffer operations.
-   * @param setWriteOnly if <code>true</code> and if the current read-drawable differs 
-   *        from the write-drawable ({@link #setGLReadDrawable(GLDrawable)}), 
-   *        only change the write-drawable. Otherwise set both drawables.
-   * @return the replaced read/write drawable
+   * @param readWrite The read/write drawable for framebuffer operations, maybe <code>null</code> to remove association.
+   * @param setWriteOnly Only change the write-drawable, if <code>setWriteOnly</code> is <code>true</code> and 
+   *                     if the {@link #getGLReadDrawable() read-drawable} differs 
+   *                     from the {@link #getGLDrawable() write-drawable}. 
+   *                     Otherwise set both drawables, read and write.
+   * @return The previous read/write drawable
    *
    * @throws GLException in case <code>null</code> is being passed or 
    *                     this context is made current on another thread.
@@ -239,6 +244,12 @@ public abstract class GLContext {
   
   /**
    * Returns the write-drawable this context uses for framebuffer operations.
+   * <p>
+   * If the read-drawable has not been changed manually via {@link #setGLReadDrawable(GLDrawable)},
+   * it equals to the write-drawable (default).
+   * </p> 
+   * @see #setGLDrawable(GLDrawable, boolean)
+   * @see #setGLReadDrawable(GLDrawable)
    */
   public abstract GLDrawable getGLDrawable();
 
@@ -259,7 +270,7 @@ public abstract class GLContext {
    *
    * @param read the read-drawable for read framebuffer operations.
    *             If null is passed, the default write drawable will be set.
-   * @return the replaced read-drawable
+   * @return the previous read-drawable
    *
    * @throws GLException in case a read drawable is not supported or
    *                     this context is made current on another thread.