Bug 776 GLContext Sharing: Refine API for relaxed and lazy GLContext sharing ; Fix GLContext memory contract (volatile)

(Unit test remarks see below)

- Add shared GLContext queries
  - Refined GLContextShareSet:
    - Use IdentityHashMap since GLContext's can only be identical w/ same reference (footprint, performance)
    - Add API doc for clarification
    - Add methods:
       - ArrayList<GLContext> getCreatedShares(final GLContext context)
       - ArrayList<GLContext> getDestroyedShares(final GLContext context)
    - Use 'final' where possible

  - Add GLContext methods:
      - boolean isShared()
      - List<GLContext> getCreatedShares()
      - List<GLContext> getDestroyedShares()

- Add GLSharedContextSetter interface defining setting a shared GLContext
  directly (GLContext) or via a GLAutoDrawable:
  - setSharedContext(GLContext)
  - setSharedAutoDrawable(GLAutoDrawable)

  Both cause initialization/creation of GLAutoDrawable's drawable/context to be postponed,
  if the shared GLContext is not yet created natively or
  the shared GLAutoDrawable's GLContext does not yet exist.

  Most of impl. resides in GLDrawableHelper

  Implemented in:
    - GLAutoDrawableBase, GLOffscreenAutoDrawable
    - GLWindow
    - AWT GLCanvas

  TODO:
    - GLJPanel
    - SWT GLCanvas

- GLDrawableFactory:
   - Add 'GLOffscreenAutoDrawable createOffscreenAutoDrawable(..)' variant w/o passing the
     optional shared GLContext _and_ specifying lazy GLContext
     creation. This allows to benefit from GLSharedContextSetter contract.
     Lazy GLContext creation is performed at 2st display() call at the latest.

     All JOGL code and unit tests use this new method now.

  - Mark 'createOffscreenAutoDrawable(..)' w/ shared GLContext argument
    and immediate GLContext creation deprecated - shall be removed in 2.2.0

- Make reference to GLContext and it's native handle volatile
  Since we rely on the query 'GLContext.isCreated()' to properly allow GLAutoDrawable's to query whether
  a shared GLContext is natively created (already), the handle must be volatile
  since such query and the actual creation may operate on different threads.

+++++

- Add/Refine shared GLContext unit tests demonstrating diff. sharing methods.

  All variants of using shared GLContext:
      com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBO*

  Most convenient way to share via setSharedAutoDrawable(GLAutoDrawable):
      com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES2[NEWT|AWT]3

  AWT use w/ JTabbedPane using setSharedAutoDrawable(GLAutoDrawable):
      com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextWithJTabbedPaneAWT

1 files changed, 8 insertions, 1 deletions

diff --git a/src/jogl/classes/com/jogamp/opengl/GLAutoDrawableDelegate.java b/src/jogl/classes/com/jogamp/opengl/GLAutoDrawableDelegate.java
index ce58d29c1..6b1bb0e5e 100644
--- a/src/jogl/classes/com/jogamp/opengl/GLAutoDrawableDelegate.java
+++ b/src/jogl/classes/com/jogamp/opengl/GLAutoDrawableDelegate.java
@@ -64,11 +64,18 @@ import jogamp.opengl.GLDrawableImpl;
  */
 public class GLAutoDrawableDelegate extends GLAutoDrawableBase implements GLAutoDrawable {
     /**
+     * <p>
+     * The {@link GLContext} can be assigned later manually via {@link GLAutoDrawable#setContext(GLContext, boolean) setContext(ctx)}
+     * <i>or</i> it will be created <i>lazily</i> at the 1st {@link GLAutoDrawable#display() display()} method call.<br>
+     * <i>Lazy</i> {@link GLContext} creation will take a shared {@link GLContext} into account
+     * which has been set {@link #setSharedContext(GLContext) directly}
+     * or {@link #setSharedAutoDrawable(GLAutoDrawable) via another GLAutoDrawable}.
+     * </p>
      * @param drawable a valid {@link GLDrawable}, may not be {@link GLDrawable#isRealized() realized} yet.
      * @param context a valid {@link GLContext},
      *                may not have been made current (created) yet,
      *                may not be associated w/ <code>drawable<code> yet,
-     *                may be <code>null</code> for lazy initialization
+     *                may be <code>null</code> for lazy initialization at 1st {@link #display()}.
      * @param upstreamWidget optional UI element holding this instance, see {@link #getUpstreamWidget()}.
      * @param ownDevice pass <code>true</code> if {@link AbstractGraphicsDevice#close()} shall be issued,
      *                  otherwise pass <code>false</code>. Closing the device is required in case