From c158a93a845e4f902272a42a150e373b3da1b802 Mon Sep 17 00:00:00 2001
From: Matthew Allum <mallum@openedhand.com>
Date: Tue, 1 Apr 2008 14:04:46 +0000
Subject: [PATCH] 2008-04-01  Matthew Allum  <mallum@openedhand.com>

        * clutter/clutter-backend.c:
        * clutter/glx/clutter-backend-glx.c:
        * clutter/glx/clutter-stage-glx.c:
        Allow NULL to be passed to _clutter_backend_ensure_context
        which essentially clears GL context. This is hooked into stage
        unrealisation.  Isn't yet quite bulletproof.
        Fixes issues with gtk-embed crasher (thanks to Neil).
---
 ChangeLog                         | 10 ++++++++++
 clutter/clutter-backend.c         | 18 ++++++++++++++----
 clutter/glx/clutter-backend-glx.c | 28 +++++++++++++++++++++-------
 clutter/glx/clutter-stage-glx.c   |  3 ++-
 4 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0b78082..1447aa3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-04-01  Matthew Allum  <mallum@openedhand.com>
+
+	* clutter/clutter-backend.c:
+	* clutter/glx/clutter-backend-glx.c:
+	* clutter/glx/clutter-stage-glx.c:
+        Allow NULL to be passed to _clutter_backend_ensure_context
+        which essentially clears GL context. This is hooked into stage
+        unrealisation.  Isn't yet quite bulletproof.  
+        Fixes issues with gtk-embed crasher (thanks to Neil).
+
 2008-04-1  Robert Bragg  <bob@o-hand.com>
 	
 	* clutter/glx/clutter-glx-texture-pixmap.c:
diff --git a/clutter/clutter-backend.c b/clutter/clutter-backend.c
index aedb393..2209060 100644
--- a/clutter/clutter-backend.c
+++ b/clutter/clutter-backend.c
@@ -184,15 +184,25 @@ _clutter_backend_ensure_context (ClutterBackend *backend, ClutterStage *stage)
   g_return_if_fail (CLUTTER_IS_BACKEND (backend));
   g_return_if_fail (CLUTTER_IS_STAGE (stage));
 
-  if (stage != current_context_stage)
+  if (stage != current_context_stage || !CLUTTER_ACTOR_IS_REALIZED(stage))
     {
-     klass = CLUTTER_BACKEND_GET_CLASS (backend);
+      if (!CLUTTER_ACTOR_IS_REALIZED(stage))
+        stage = NULL;
+      
+      klass = CLUTTER_BACKEND_GET_CLASS (backend);
       if (G_LIKELY(klass->ensure_context))
         klass->ensure_context (backend, stage);
+      
+      /* FIXME: With a NULL stage and thus no active context it may make more
+       * sense to clean the context but then re call with the default stage 
+       * so at least there is some kind of context in place (as to avoid
+       * potential issue of GL calls with no context)
+      */
 
       current_context_stage = stage;
-
-      CLUTTER_SET_PRIVATE_FLAGS (stage, CLUTTER_ACTOR_SYNC_MATRICES);
+      
+      if (stage)
+        CLUTTER_SET_PRIVATE_FLAGS (stage, CLUTTER_ACTOR_SYNC_MATRICES);
     }
 }
 
diff --git a/clutter/glx/clutter-backend-glx.c b/clutter/glx/clutter-backend-glx.c
index 69f98d2..de6eaad 100644
--- a/clutter/glx/clutter-backend-glx.c
+++ b/clutter/glx/clutter-backend-glx.c
@@ -350,16 +350,30 @@ clutter_backend_glx_ensure_context (ClutterBackend *backend,
   ClutterBackendGLX *backend_glx;
   ClutterStageGLX   *stage_glx;
   ClutterStageX11   *stage_x11;
+  ClutterBackendX11 *backend_x11;
 
-  stage_x11 = CLUTTER_STAGE_X11(stage);
-  stage_glx = CLUTTER_STAGE_GLX(stage);
-  backend_glx = CLUTTER_BACKEND_GLX(backend);
+  if (stage == NULL)
+    {
+      backend_x11 = CLUTTER_BACKEND_X11(backend);
+      CLUTTER_NOTE (MULTISTAGE, "Clearing all context");
 
-  CLUTTER_NOTE (MULTISTAGE, "setting context for stage:%p", stage );
+      glXMakeCurrent (backend_x11->xdpy, None, NULL);
+    }
+  else
+    {
+      stage_glx = CLUTTER_STAGE_GLX(stage);
+      stage_x11 = CLUTTER_STAGE_X11(stage);
+      backend_glx = CLUTTER_BACKEND_GLX(backend);
+
+      g_return_if_fail (stage_x11->xwin != None);
+      g_return_if_fail (backend_glx->gl_context != None);
 
-  glXMakeCurrent (stage_x11->xdpy, 
-                  stage_x11->xwin, 
-                  backend_glx->gl_context);
+      CLUTTER_NOTE (MULTISTAGE, "setting context for stage:%p", stage );
+
+      glXMakeCurrent (stage_x11->xdpy, 
+                      stage_x11->xwin, 
+                      backend_glx->gl_context);
+    }
 }
 
 static void
diff --git a/clutter/glx/clutter-stage-glx.c b/clutter/glx/clutter-stage-glx.c
index 00dacbd..d7eb02b 100644
--- a/clutter/glx/clutter-stage-glx.c
+++ b/clutter/glx/clutter-stage-glx.c
@@ -99,7 +99,8 @@ clutter_stage_glx_unrealize (ClutterActor *actor)
         stage_x11->xwin = None;
     }
 
-  glXMakeCurrent (stage_x11->xdpy, None, NULL);
+  /* As unrealised the context will now get cleared */
+  clutter_stage_ensure_current (CLUTTER_STAGE(stage_glx));
 
   XSync (stage_x11->xdpy, False);
 
-- 
2.7.4