[cogl] egl-gdl: Provide defaults to be able to initialize a "dummy" context

[Damien Lespiau <dlespiau src gnome org>]

commit 2c3827aced46547c8e8ab441e1ff2ebf3e02b624
Author: Damien Lespiau <damien lespiau intel com>
Date:   Tue Jul 26 17:32:47 2011 +0300

    egl-gdl: Provide defaults to be able to initialize a "dummy" context
    
    If we are being called without any GDL specific call (either the plane
    we want to render to or the swap chain length) we can provide sane
    defaults to still be able to create a context and a surface.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=655355

 cogl/cogl-display.c           |    4 ++++
 cogl/winsys/cogl-winsys-egl.c |    8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/cogl/cogl-display.c b/cogl/cogl-display.c
index 8669253..ec13aa4 100644
--- a/cogl/cogl-display.c
+++ b/cogl/cogl-display.c
@@ -97,6 +97,10 @@ cogl_display_new (CoglRenderer *renderer,
 
   display->setup = FALSE;
 
+#ifdef COGL_HAS_EGL_PLATFORM_GDL_SUPPORT
+  display->gdl_plane = GDL_PLANE_ID_UPP_C;
+#endif
+
   return _cogl_display_object_new (display);
 }
 
diff --git a/cogl/winsys/cogl-winsys-egl.c b/cogl/winsys/cogl-winsys-egl.c
index db01709..4ee208a 100644
--- a/cogl/winsys/cogl-winsys-egl.c
+++ b/cogl/winsys/cogl-winsys-egl.c
@@ -1091,9 +1091,13 @@ gdl_plane_init (CoglDisplay *display, GError **error)
   if (rc == GDL_SUCCESS)
     rc = gdl_plane_set_attr (GDL_PLANE_DST_RECT, &dstRect);
 
+  /* Default to triple buffering if we don't have an onscreen template */
   if (rc == GDL_SUCCESS)
-    rc = gdl_plane_set_uint (GDL_PLANE_NUM_GFX_SURFACES,
-                             display->swap_chain->length);
+    if (display->onscreen_template)
+      rc = gdl_plane_set_uint (GDL_PLANE_NUM_GFX_SURFACES,
+                               display->onscreen_template->swap_chain->length);
+    else
+      rc = gdl_plane_set_uint (GDL_PLANE_NUM_GFX_SURFACES, 3);
 
   if (rc == GDL_SUCCESS)
     rc = gdl_plane_config_end (GDL_FALSE);