[gnome-games/glchess-vala] Delete GLX context when widget destroyed

[Robert Ancell <rancell src gnome org>]

commit 8cb31805ae8a81dde6b8da86d0c79a6fc5396ffc
Author: Robert Ancell <robert ancell canonical com>
Date:   Sat Dec 11 18:41:12 2010 +1100

    Delete GLX context when widget destroyed

 glchess/src/chess-view-3d.vala |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)
---
diff --git a/glchess/src/chess-view-3d.vala b/glchess/src/chess-view-3d.vala
index b83d6b2..5bece02 100644
--- a/glchess/src/chess-view-3d.vala
+++ b/glchess/src/chess-view-3d.vala
@@ -39,6 +39,7 @@ private class ChessView3D : ChessView
 
         add_events (Gdk.EventMask.BUTTON_PRESS_MASK);
         realize.connect (realize_cb);
+        unrealize.connect (unrealize_cb);
 
         double_buffered = false;
         try
@@ -102,7 +103,7 @@ private class ChessView3D : ChessView
                       4, 5, 9, 8,  4, 8, 11, 7,  7, 11, 10, 6,  6, 10, 9, 5};
     }
     
-    public void realize_cb ()
+    private void realize_cb ()
     {
         int[] attributes = { GLX_RGBA,
                              GLX_RED_SIZE, 1,
@@ -121,6 +122,18 @@ private class ChessView3D : ChessView
         context = glXCreateContext (display, visual, null, true);
     }
 
+    private void unrealize_cb ()
+    {
+        /* Wait for any pending GL calls to end */
+        if (drawable == glXGetCurrentDrawable ())
+        {
+            glXWaitGL ();
+            glXMakeCurrent (display, X.None, (GLX.Context) null);
+        }
+
+        glXDestroyContext (display, context);
+    }
+
     public override bool configure_event (Gdk.EventConfigure event)
     {
         int short_edge = int.min (get_allocated_width (), get_allocated_height ());