cogl: Remove use_stereo_stage config

Nothing sets it from the X11 backend API, so just get rid of it

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3915>

cogl/cogl/cogl-framebuffer-private.h

@@ -54,7 +54,6 @@ typedef struct _CoglFramebufferDriverConfig
 typedef struct
 {
   gboolean need_stencil;
-  gboolean stereo_enabled;
 } CoglFramebufferConfig;
 
 /* XXX: The order of these indices determines the order they are

cogl/cogl/cogl-onscreen-template.c

@@ -57,11 +57,3 @@ cogl_onscreen_template_new (void)
 
   return onscreen_template;
 }
-
-void
-cogl_onscreen_template_set_stereo_enabled (
-					   CoglOnscreenTemplate *onscreen_template,
-					   gboolean enabled)
-{
-  onscreen_template->config.stereo_enabled = enabled;
-}

cogl/cogl/cogl-onscreen-template.h

@@ -51,20 +51,4 @@ G_DECLARE_FINAL_TYPE (CoglOnscreenTemplate, cogl_onscreen_template,
 COGL_EXPORT CoglOnscreenTemplate *
 cogl_onscreen_template_new (void);
 
-/**
- * cogl_onscreen_template_set_stereo_enabled:
- * @onscreen_template: A #CoglOnscreenTemplate template framebuffer
- * @enabled: Whether framebuffers are created with stereo buffers
- *
- * Sets whether future #CoglOnscreen framebuffers derived from this
- * template are attempted to be created with both left and right
- * buffers, for use with stereo display. If the display system
- * does not support stereo, then creation of the framebuffer will
- * fail.
- */
-COGL_EXPORT void
-cogl_onscreen_template_set_stereo_enabled (
-  CoglOnscreenTemplate *onscreen_template,
-  gboolean              enabled);
-
 G_END_DECLS

cogl/cogl/winsys/cogl-winsys-glx.c

@@ -521,11 +521,6 @@ glx_attributes_from_framebuffer_config (CoglDisplay                 *display,
   attributes[i++] = 1;
   attributes[i++] = GLX_STENCIL_SIZE;
   attributes[i++] = config->need_stencil ? 2 : 0;
-  if (config->stereo_enabled)
-    {
-      attributes[i++] = GLX_STEREO;
-      attributes[i++] = TRUE;
-    }
 
   attributes[i++] = None;
 

src/backends/x11/meta-clutter-backend-x11.c

@@ -36,6 +36,7 @@
 #include "clutter/clutter.h"
 #include "cogl/cogl-xlib-renderer.h"
 #include "core/bell.h"
+#include "glib.h"
 #include "meta/meta-backend.h"
 
 typedef struct _MetaClutterBackendX11Private
@@ -65,75 +66,23 @@ static const gchar *atom_names[] = {
 
 #define N_ATOM_NAMES G_N_ELEMENTS (atom_names)
 
-/* various flags corresponding to pre init setup calls */
-static gboolean clutter_enable_stereo = FALSE;
-
-static gboolean
-check_onscreen_template (CoglRenderer         *renderer,
-                         CoglOnscreenTemplate *onscreen_template,
-                         gboolean              enable_stereo,
-                         GError              **error)
-{
-  GError *internal_error = NULL;
-
-  cogl_onscreen_template_set_stereo_enabled (onscreen_template,
-					     clutter_enable_stereo);
-
-  /* cogl_renderer_check_onscreen_template() is actually just a
-   * shorthand for creating a CoglDisplay, and calling
-   * cogl_display_setup() on it, then throwing the display away. If we
-   * could just return that display, then it would be more efficient
-   * not to use cogl_renderer_check_onscreen_template(). However, the
-   * backend API requires that we return an CoglDisplay that has not
-   * yet been setup, so one way or the other we'll have to discard the
-   * first display and make a new fresh one.
-   */
-  if (cogl_renderer_check_onscreen_template (renderer, onscreen_template, &internal_error))
-    {
-      clutter_enable_stereo = enable_stereo;
-
-      return TRUE;
-    }
-  else
-    {
-      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-                           internal_error != NULL
-                           ? internal_error->message
-                           : "Creation of a CoglDisplay failed");
-
-      g_clear_error (&internal_error);
-
-      return FALSE;
-    }
-}
-
 static CoglDisplay *
 meta_clutter_backend_x11_get_display (ClutterBackend  *clutter_backend,
                                       CoglRenderer    *renderer,
                                       GError         **error)
 {
-  CoglOnscreenTemplate *onscreen_template;
+  g_autoptr (CoglOnscreenTemplate) onscreen_template = NULL;
   CoglDisplay *display = NULL;
   gboolean res = FALSE;
 
   onscreen_template = cogl_onscreen_template_new ();
-
+  res = cogl_renderer_check_onscreen_template (renderer,
-  /* It's possible that the current renderer doesn't support transparency
+                                               onscreen_template,
-   * or doesn't support stereo, so we try the different combinations.
+                                               error);
-   */
-  if (clutter_enable_stereo)
-    res = check_onscreen_template (renderer, onscreen_template,
-                                   TRUE, error);
-
-  if (!res)
-    res = check_onscreen_template (renderer, onscreen_template,
-                                   FALSE, error);
 
   if (res)
     display = cogl_display_new (renderer, onscreen_template);
 
-  g_object_unref (onscreen_template);
-
   return display;
 }
 
@@ -239,25 +188,3 @@ meta_clutter_backend_x11_new (MetaBackend *backend)
 
   return clutter_backend_x11;
 }
-
-void
-meta_clutter_x11_set_use_stereo_stage (gboolean use_stereo)
-{
-  if (_clutter_context_is_initialized ())
-    {
-      g_warning ("%s() can only be used before calling clutter_init()",
-                 G_STRFUNC);
-      return;
-    }
-
-  g_debug ("STEREO stages are %s",
-           use_stereo ? "enabled" : "disabled");
-
-  clutter_enable_stereo = use_stereo;
-}
-
-gboolean
-meta_clutter_x11_get_use_stereo_stage (void)
-{
-  return clutter_enable_stereo;
-}

src/backends/x11/meta-clutter-backend-x11.h

@@ -57,6 +57,3 @@ G_DECLARE_FINAL_TYPE (MetaClutterBackendX11, meta_clutter_backend_x11,
                       ClutterBackend)
 
 MetaClutterBackendX11 * meta_clutter_backend_x11_new (MetaBackend *backend);
-
-void meta_clutter_x11_set_use_stereo_stage (gboolean use_stereo);
-gboolean meta_clutter_x11_get_use_stereo_stage (void);