Bug 1055 - Access and query shared master GLContext in a deterministic fashion ; Don't use arbitrary shared context as 'master'.

GLContext* passes the shared-master to GLContextShareSet,
which only creates a sets of shared contexts
without differentiating the master context.

GLContext*'s shared-slave attempts to lock
the realized shared-master's surface at creation.

Currently only an arbitrary shared context is selected
due to the missing 'master' identity.
The arbitrary shared context's surface is locked
and its shared context handle used to create the slave context.

Lacking of using the user given shared-master
can lead to deadlock situations - and locking a 'wrong' surface.

+++

The patch:

  - Allows query the user given shared-master!

  - Use the user given shared-master for locking and it's
    context handle for the slave's creation.

  - The shared-context mapping maps each shared-master
    to a shared-slave within one shared-context-set,
    allowing deterministic and individual shared-master queries.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/jogl/classes/javax/media/opengl/GLContext.java b/src/jogl/classes/javax/media/opengl/GLContext.java
index 9389ccabb..f4ba3c0b7 100644
--- a/src/jogl/classes/javax/media/opengl/GLContext.java
+++ b/src/jogl/classes/javax/media/opengl/GLContext.java
@@ -250,6 +250,16 @@ public abstract class GLContext {
       return GLContextShareSet.isShared(this);
   }
 
+  /**
+   * Returns the shared master GLContext of this GLContext if shared, otherwise return <code>null</code>.
+   * <p>
+   * Returns this GLContext, if it is a shared master.
+   * </p>
+   */
+  public final GLContext getSharedMaster() {
+      return GLContextShareSet.getSharedMaster(this);
+  }
+
   /** Returns a new list of created GLContext shared with this GLContext. */
   public final List<GLContext> getCreatedShares() {
       return GLContextShareSet.getCreatedShares(this);