[cogl] examples/cogl-x11-tfp.c: Wait for the window to be mapped

[Owen Taylor <otaylor src gnome org>]

commit 0cdb938551f6aaafac80758829e21c0cb7b1f81d
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Sun Apr 27 00:07:53 2014 -0400

    examples/cogl-x11-tfp.c: Wait for the window to be mapped
    
    Wait for the main window (and hence the window we create within
    the main window to redirect) to be mapped and become viewable
    before we try to call XCompositeNameWindowPixmap() -
    XComposeNameWindowPixmap() produces a BadMatch error on a
    non-viewable window.
    
    Reviewed-by: Robert Bragg <robert bragg intel com>

 examples/cogl-x11-tfp.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/examples/cogl-x11-tfp.c b/examples/cogl-x11-tfp.c
index b5803d0..b585943 100644
--- a/examples/cogl-x11-tfp.c
+++ b/examples/cogl-x11-tfp.c
@@ -139,7 +139,8 @@ main (int argc, char **argv)
                                     DefaultRootWindow (xdpy),
                                     xvisinfo->visual,
                                     AllocNone);
-  mask = CWBorderPixel | CWColormap;
+  xattr.event_mask = StructureNotifyMask;
+  mask = CWBorderPixel | CWColormap | CWEventMask;
 
   xwin = XCreateWindow (xdpy,
                         DefaultRootWindow (xdpy),
@@ -171,6 +172,14 @@ main (int argc, char **argv)
 
   gc = XCreateGC (xdpy, tfp_xwin, 0, NULL);
 
+  while (TRUE)
+    {
+      XWindowEvent (xdpy, xwin, StructureNotifyMask, &xev);
+
+      if (xev.xany.type == MapNotify)
+        break;
+    }
+
   pixmap = XCompositeNameWindowPixmap (xdpy, tfp_xwin);
 
   tfp = cogl_texture_pixmap_x11_new (ctx, pixmap, TRUE, &error);