[mutter] Work around COGL bug causing flash for new windows

[Owen Taylor <otaylor src gnome org>]

commit 092cc47afcaa02f3a92d000dba5f5756a3336771
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Sat May 8 17:11:49 2010 -0400

    Work around COGL bug causing flash for new windows
    
    COGL bug http://bugzilla.openedhand.com/show_bug.cgi?id=2110 results
    in pending drawing at the time of cogl_offscreen_new_to_texture() going
    to the newly created framebuffer rather than the stage.
    
    This would result in most windows being missing for the first frame
    when a new window is mapped.
    
    Work around this by calling cogl_flush() before
    cogl_offscreen_new_to_texture().
    
    https://bugzilla.gnome.org/show_bug.cgi?id=618138

 src/compositor/mutter-texture-tower.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/mutter-texture-tower.c b/src/compositor/mutter-texture-tower.c
index 67f878b..f9307cb 100644
--- a/src/compositor/mutter-texture-tower.c
+++ b/src/compositor/mutter-texture-tower.c
@@ -422,7 +422,12 @@ texture_tower_revalidate_fbo (MutterTextureTower *tower,
   CoglMatrix modelview;
 
   if (tower->fbos[level] == COGL_INVALID_HANDLE)
-    tower->fbos[level] = cogl_offscreen_new_to_texture (dest_texture);
+    {
+      /* Work around http://bugzilla.openedhand.com/show_bug.cgi?id=2110 */
+      cogl_flush();
+
+      tower->fbos[level] = cogl_offscreen_new_to_texture (dest_texture);
+    }
 
   if (tower->fbos[level] == COGL_INVALID_HANDLE)
     return FALSE;