mutter/SOURCES/0001-Add-support-for-quad-buffer-stereo.patch

From fd67e75df470b50510b68ccf0f52b0b98d05c63f Mon Sep 17 00:00:00 2001
From: "Owen W. Taylor" <otaylor@fishsoup.net>
Date: Thu, 8 May 2014 18:44:15 -0400
Subject: [PATCH] Add support for quad-buffer stereo

Track the stereo status of windows using the new EXT_stereo_tree
GLX extension.

When stereo is enabled or disabled, a restart is triggered via
meta_restart() after a timeout, setting a _META_ENABLE_STEREO
property on the root window to indicate whether we should
turn on a stereo stage for clutter. The property avoids a loop,
since we need to enable stereo *before* initializing Clutter and GL,
but we need GL to figure out whether we have stereo windows.

Stereo windows are drawn to the stage using new functionality
in Cogl to setup a stereo context, select which buffer to draw
to, and draw either the left or right buffer of a stereo
texture_from_pixmap.
---
 src/compositor/compositor-private.h          |   9 ++
 src/compositor/compositor.c                  | 125 +++++++++++++++
 src/compositor/meta-shaped-texture-private.h |   5 +-
 src/compositor/meta-shaped-texture.c         |  85 +++++++++-
 src/compositor/meta-surface-actor-wayland.c  |   2 +-
 src/compositor/meta-surface-actor-x11.c      |  54 ++++++-
 src/compositor/meta-surface-actor-x11.h      |   5 +
 src/compositor/meta-window-actor-private.h   |   5 +
 src/compositor/meta-window-actor.c           |  22 +++
 src/core/main.c                              |   4 +
 src/core/stereo.c                            | 154 +++++++++++++++++++
 src/core/stereo.h                            |  28 ++++
 src/meson.build                              |   2 +
 src/wayland/meta-wayland-surface.c           |   2 +-
 14 files changed, 482 insertions(+), 20 deletions(-)
 create mode 100644 src/core/stereo.c
 create mode 100644 src/core/stereo.h

diff --git a/src/compositor/compositor-private.h b/src/compositor/compositor-private.h
index 6ab33416c..f70087512 100644
--- a/src/compositor/compositor-private.h
+++ b/src/compositor/compositor-private.h
@@ -24,6 +24,10 @@ struct _MetaCompositor
   gint64          server_time_query_time;
   gint64          server_time_offset;
 
+  int             glx_opcode;
+  guint           stereo_tree_ext : 1;
+  guint           have_stereo_windows : 1;
+
   guint           server_time_is_monotonic_time : 1;
 
   ClutterActor          *stage, *window_group, *top_window_group, *feedback_group;
@@ -63,6 +67,11 @@ void     meta_end_modal_for_plugin   (MetaCompositor   *compositor,
 gint64 meta_compositor_monotonic_time_to_server_time (MetaDisplay *display,
                                                       gint64       monotonic_time);
 
+gboolean meta_compositor_window_is_stereo     (MetaDisplay *display,
+                                               Window       xwindow);
+void     meta_compositor_select_stereo_notify (MetaDisplay *display,
+                                               Window       xwindow);
+
 void meta_compositor_flash_window (MetaCompositor *compositor,
                                    MetaWindow     *window);
 
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index 2a2c8fb3b..6c08c8fe4 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -69,6 +69,8 @@
 #include "core/core.h"
 #include "core/display-private.h"
 #include "core/frame.h"
+#include "core/stack-tracker.h"
+#include "core/stereo.h"
 #include "core/util-private.h"
 #include "core/window-private.h"
 #include "meta/compositor-mutter.h"
@@ -514,6 +516,94 @@ redirect_windows (MetaX11Display *x11_display)
     }
 }
 
+#define GLX_STEREO_TREE_EXT        0x20F5
+#define GLX_STEREO_NOTIFY_MASK_EXT 0x00000001
+#define GLX_STEREO_NOTIFY_EXT      0x00000000
+
+typedef struct {
+  int type;
+  unsigned long serial;
+  Bool send_event;
+  Display *display;
+  int extension;
+  int evtype;
+  Drawable window;
+  Bool stereo_tree;
+} StereoNotifyEvent;
+
+static gboolean
+display_has_stereo_tree_ext (MetaX11Display *x11_display)
+{
+  Display     *xdisplay = x11_display->xdisplay;
+  const char  *extensions_string;
+
+  static const char * (*query_extensions_string) (Display *display,
+                                                  int      screen);
+
+  if (query_extensions_string == NULL)
+    query_extensions_string =
+      (const char * (*) (Display *, int))
+      cogl_get_proc_address ("glXQueryExtensionsString");
+
+  extensions_string = query_extensions_string (xdisplay,
+                                               meta_x11_display_get_screen_number (x11_display));
+
+  return extensions_string && strstr (extensions_string, "EXT_stereo_tree") != 0;
+}
+
+#include <GL/gl.h>
+
+gboolean
+meta_compositor_window_is_stereo (MetaDisplay *display,
+                                  Window       xwindow)
+{
+  MetaCompositor *compositor = get_compositor_for_display (display);
+  Display *xdisplay = meta_x11_display_get_xdisplay (display->x11_display);
+
+  static int (*query_drawable) (Display      *dpy,
+                                Drawable      draw,
+                                int           attribute,
+                                unsigned int *value);
+
+  if (compositor->stereo_tree_ext)
+    {
+      unsigned int stereo_tree = 0;
+
+      if (query_drawable == NULL)
+        query_drawable =
+          (int (*) (Display *, Drawable, int, unsigned int *))
+          cogl_get_proc_address ("glXQueryDrawable");
+
+      query_drawable (xdisplay, xwindow, GLX_STEREO_TREE_EXT, &stereo_tree);
+
+      return stereo_tree != 0;
+    }
+  else
+    return FALSE;
+}
+
+void
+meta_compositor_select_stereo_notify (MetaDisplay *display,
+                                      Window       xwindow)
+{
+  MetaCompositor *compositor = get_compositor_for_display (display);
+  Display *xdisplay = meta_x11_display_get_xdisplay (display->x11_display);
+
+  static void (*select_event) (Display      *dpy,
+                               Drawable      draw,
+                               unsigned long event_mask);
+
+  if (compositor->stereo_tree_ext)
+    {
+      if (select_event == NULL)
+        select_event =
+          (void (*) (Display *, Drawable, unsigned long))
+          cogl_get_proc_address ("glXSelectEvent");
+
+      select_event (xdisplay, xwindow, GLX_STEREO_NOTIFY_MASK_EXT);
+    }
+}
+
 void
 meta_compositor_manage (MetaCompositor *compositor)
 {
@@ -525,6 +615,8 @@ meta_compositor_manage (MetaCompositor *compositor)
     {
       xdisplay = display->x11_display->xdisplay;
       meta_x11_display_set_cm_selection (display->x11_display);
+
+      compositor->stereo_tree_ext = display_has_stereo_tree_ext (display->x11_display);
     }
 
   compositor->stage = meta_backend_get_stage (backend);
@@ -822,6 +914,23 @@ meta_compositor_process_event (MetaCompositor *compositor,
       if (window)
         process_damage (compositor, (XDamageNotifyEvent *) event, window);
     }
+  else if (!meta_is_wayland_compositor () &&
+           event->type == GenericEvent &&
+           event->xcookie.extension == compositor->glx_opcode)
+    {
+      if (event->xcookie.evtype == GLX_STEREO_NOTIFY_EXT)
+        {
+          StereoNotifyEvent *stereo_event = (StereoNotifyEvent *)(event->xcookie.data);
+          window = meta_x11_display_lookup_x_window (x11_display, stereo_event->window);
+
+          if (window != NULL)
+            {
+              MetaWindowActor *window_actor = META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
+              meta_window_actor_stereo_notify (window_actor, stereo_event->stereo_tree);
+              meta_stack_tracker_queue_sync_stack (window->display->stack_tracker);
+            }
+        }
+    }
 
   if (compositor->have_x11_sync_object)
     meta_sync_ring_handle_event (event);
@@ -1038,6 +1147,7 @@ meta_compositor_sync_stack (MetaCompositor  *compositor,
 			    GList	    *stack)
 {
   GList *old_stack;
+  int stereo_window_count = 0;
 
   /* This is painful because hidden windows that we are in the process
    * of animating out of existence. They'll be at the bottom of the
@@ -1113,6 +1223,8 @@ meta_compositor_sync_stack (MetaCompositor  *compositor,
        * near the front of the other.)
        */
       compositor->windows = g_list_prepend (compositor->windows, actor);
+      if (meta_window_actor_is_stereo (actor))
+        stereo_window_count++;
 
       stack = g_list_remove (stack, window);
       old_stack = g_list_remove (old_stack, actor);
@@ -1120,6 +1232,8 @@ meta_compositor_sync_stack (MetaCompositor  *compositor,
 
   sync_actor_stacking (compositor);
 
+  meta_stereo_set_have_stereo_windows (stereo_window_count > 0);
+
   if (compositor->top_window_actor)
     g_signal_handlers_disconnect_by_func (compositor->top_window_actor,
                                           on_top_window_actor_destroyed,
@@ -1325,6 +1439,17 @@ meta_compositor_new (MetaDisplay *display)
                                            meta_post_paint_func,
                                            compositor,
                                            NULL);
+  if (!meta_is_wayland_compositor ())
+    {
+      Display *xdisplay = meta_x11_display_get_xdisplay (display->x11_display);
+      int glx_major_opcode, glx_first_event, glx_first_error;
+
+      if (XQueryExtension (xdisplay,
+                           "GLX",
+                           &glx_major_opcode, &glx_first_event, &glx_first_error))
+        compositor->glx_opcode = glx_major_opcode;
+    }
+
   return compositor;
 }
 
diff --git a/src/compositor/meta-shaped-texture-private.h b/src/compositor/meta-shaped-texture-private.h
index a86a2bff0..d0efdd4dc 100644
--- a/src/compositor/meta-shaped-texture-private.h
+++ b/src/compositor/meta-shaped-texture-private.h
@@ -31,8 +31,9 @@
 #include "meta/meta-shaped-texture.h"
 
 ClutterActor *meta_shaped_texture_new (void);
-void meta_shaped_texture_set_texture (MetaShapedTexture *stex,
-                                      CoglTexture       *texture);
+void meta_shaped_texture_set_textures (MetaShapedTexture *stex,
+                                       CoglTexture       *texture,
+                                       CoglTexture       *texture_right);
 void meta_shaped_texture_set_is_y_inverted (MetaShapedTexture *stex,
                                             gboolean           is_y_inverted);
 void meta_shaped_texture_set_snippet (MetaShapedTexture *stex,
diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index d64e214e5..332b4c814 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -88,8 +88,10 @@ struct _MetaShapedTexture
   ClutterActor parent;
 
   MetaTextureTower *paint_tower;
+  MetaTextureTower *paint_tower_right;
 
   CoglTexture *texture;
+  CoglTexture *texture_right;
   CoglTexture *mask_texture;
   CoglSnippet *snippet;
 
@@ -160,6 +162,7 @@ static void
 meta_shaped_texture_init (MetaShapedTexture *stex)
 {
   stex->paint_tower = meta_texture_tower_new ();
+  stex->paint_tower_right = NULL; /* demand create */
 
   stex->texture = NULL;
   stex->mask_texture = NULL;
@@ -297,7 +300,11 @@ meta_shaped_texture_dispose (GObject *object)
     meta_texture_tower_free (stex->paint_tower);
   stex->paint_tower = NULL;
 
+  g_clear_pointer (&stex->paint_tower, meta_texture_tower_free);
+  g_clear_pointer (&stex->paint_tower_right, meta_texture_tower_free);
+
   g_clear_pointer (&stex->texture, cogl_object_unref);
+  g_clear_pointer (&stex->texture_right, cogl_object_unref);
   g_clear_pointer (&stex->opaque_region, cairo_region_destroy);
 
   meta_shaped_texture_set_mask_texture (stex, NULL);
@@ -507,8 +514,9 @@ paint_clipped_rectangle (MetaShapedTexture     *stex,
 }
 
 static void
-set_cogl_texture (MetaShapedTexture *stex,
-                  CoglTexture       *cogl_tex)
+set_cogl_textures (MetaShapedTexture *stex,
+                   CoglTexture       *cogl_tex,
+                   CoglTexture       *cogl_tex_right)
 {
   int width, height;
 
@@ -516,8 +524,11 @@ set_cogl_texture (MetaShapedTexture *stex,
 
   if (stex->texture)
     cogl_object_unref (stex->texture);
+  if (stex->texture_right)
+    cogl_object_unref (stex->texture_right);
 
   stex->texture = cogl_tex;
+  stex->texture_right = cogl_tex_right;
 
   if (cogl_tex != NULL)
     {
@@ -531,6 +542,9 @@ set_cogl_texture (MetaShapedTexture *stex,
       height = 0;
     }
 
+  if (cogl_tex_right != NULL)
+    cogl_object_ref (cogl_tex_right);
+
   if (stex->tex_width != width ||
       stex->tex_height != height)
     {
@@ -544,8 +558,23 @@ set_cogl_texture (MetaShapedTexture *stex,
    * previous buffer. We only queue a redraw in response to surface
    * damage. */
 
+  if (cogl_tex_right != NULL)
+    {
+      if (stex->paint_tower_right == NULL)
+        stex->paint_tower_right = meta_texture_tower_new ();
+    }
+  else
+    {
+      g_clear_pointer (&stex->paint_tower_right, meta_texture_tower_free);
+    }
+
   if (stex->create_mipmaps)
-    meta_texture_tower_set_base_texture (stex->paint_tower, cogl_tex);
+    {
+      meta_texture_tower_set_base_texture (stex->paint_tower, cogl_tex);
+
+      if (stex->paint_tower_right)
+        meta_texture_tower_set_base_texture (stex->paint_tower_right, cogl_tex_right);
+    }
 }
 
 static gboolean
@@ -779,7 +808,9 @@ meta_shaped_texture_paint (ClutterActor *actor)
 {
   MetaShapedTexture *stex = META_SHAPED_TEXTURE (actor);
   CoglTexture *paint_tex;
+  CoglTexture *paint_tex_right = NULL;
   CoglFramebuffer *fb;
+  gboolean stereo;
 
   if (!stex->texture)
     return;
@@ -841,7 +872,32 @@ meta_shaped_texture_paint (ClutterActor *actor)
     return;
 
   fb = cogl_get_draw_framebuffer ();
-  do_paint (META_SHAPED_TEXTURE (actor), fb, paint_tex, stex->clip_region);
+
+  stereo = stex->texture_right && cogl_framebuffer_get_is_stereo (fb);
+
+  if (stereo)
+    {
+      if (stex->create_mipmaps)
+	paint_tex_right = meta_texture_tower_get_paint_texture (stex->paint_tower_right);
+
+      if (!paint_tex_right)
+	paint_tex_right = COGL_TEXTURE (stex->texture_right);
+    }
+  else
+    paint_tex_right = NULL;
+
+  if (stereo)
+    cogl_framebuffer_set_stereo_mode (fb, COGL_STEREO_LEFT);
+  do_paint (stex, fb, paint_tex, stex->clip_region);
+  if (stereo)
+    cogl_framebuffer_set_stereo_mode (fb, COGL_STEREO_BOTH);
+
+  if (paint_tex_right != NULL)
+    {
+      cogl_framebuffer_set_stereo_mode (fb, COGL_STEREO_RIGHT);
+      do_paint (stex, fb, paint_tex_right, stex->clip_region);
+      cogl_framebuffer_set_stereo_mode (fb, COGL_STEREO_BOTH);
+    }
 }
 
 static void
@@ -915,6 +971,12 @@ meta_shaped_texture_set_create_mipmaps (MetaShapedTexture *stex,
       stex->create_mipmaps = create_mipmaps;
       base_texture = create_mipmaps ? stex->texture : NULL;
       meta_texture_tower_set_base_texture (stex->paint_tower, base_texture);
+
+      if (stex->paint_tower_right)
+        {
+          base_texture = create_mipmaps ? stex->texture_right : NULL;
+          meta_texture_tower_set_base_texture (stex->paint_tower_right, base_texture);
+        }
     }
 }
 
@@ -1046,6 +1108,12 @@ meta_shaped_texture_update_area (MetaShapedTexture *stex,
                                   clip.y,
                                   clip.width,
                                   clip.height);
+  if (stex->paint_tower_right)
+    meta_texture_tower_update_area (stex->paint_tower_right,
+                                    clip.x,
+                                    clip.y,
+                                    clip.width,
+                                    clip.height);
 
   stex->prev_invalidation = stex->last_invalidation;
   stex->last_invalidation = g_get_monotonic_time ();
@@ -1092,17 +1160,18 @@ meta_shaped_texture_update_area (MetaShapedTexture *stex,
 }
 
 /**
- * meta_shaped_texture_set_texture:
+ * meta_shaped_texture_set_textures:
  * @stex: The #MetaShapedTexture
  * @pixmap: The #CoglTexture to display
  */
 void
-meta_shaped_texture_set_texture (MetaShapedTexture *stex,
-                                 CoglTexture       *texture)
+meta_shaped_texture_set_textures (MetaShapedTexture *stex,
+                                  CoglTexture       *texture,
+                                  CoglTexture       *texture_right)
 {
   g_return_if_fail (META_IS_SHAPED_TEXTURE (stex));
 
-  set_cogl_texture (stex, texture);
+  set_cogl_textures (stex, texture, texture_right);
 }
 
 /**
diff --git a/src/compositor/meta-surface-actor-wayland.c b/src/compositor/meta-surface-actor-wayland.c
index f8d6c32b7..a75c4dd09 100644
--- a/src/compositor/meta-surface-actor-wayland.c
+++ b/src/compositor/meta-surface-actor-wayland.c
@@ -182,7 +182,7 @@ meta_surface_actor_wayland_dispose (GObject *object)
   MetaShapedTexture *stex =
     meta_surface_actor_get_texture (META_SURFACE_ACTOR (self));
 
-  meta_shaped_texture_set_texture (stex, NULL);
+  meta_shaped_texture_set_textures (stex, NULL, NULL);
   if (self->surface)
     {
       g_object_remove_weak_pointer (G_OBJECT (self->surface),
diff --git a/src/compositor/meta-surface-actor-x11.c b/src/compositor/meta-surface-actor-x11.c
index 244b1e885..3cd164d77 100644
--- a/src/compositor/meta-surface-actor-x11.c
+++ b/src/compositor/meta-surface-actor-x11.c
@@ -32,6 +32,7 @@
 #include "cogl/winsys/cogl-texture-pixmap-x11.h"
 #include "compositor/meta-cullable.h"
 #include "compositor/meta-shaped-texture-private.h"
+#include "compositor-private.h"
 #include "core/window-private.h"
 #include "meta/meta-x11-errors.h"
 #include "x11/meta-x11-display-private.h"
@@ -46,6 +47,7 @@ struct _MetaSurfaceActorX11
   MetaDisplay *display;
 
   CoglTexture *texture;
+  CoglTexture *texture_right;
   Pixmap pixmap;
   Damage damage;
 
@@ -61,6 +63,8 @@ struct _MetaSurfaceActorX11
   guint size_changed : 1;
 
   guint unredirected   : 1;
+
+  guint stereo : 1;
 };
 
 G_DEFINE_TYPE (MetaSurfaceActorX11,
@@ -96,7 +100,7 @@ detach_pixmap (MetaSurfaceActorX11 *self)
    * you are supposed to be able to free a GLXPixmap after freeing the underlying
    * pixmap, but it certainly doesn't work with current DRI/Mesa
    */
-  meta_shaped_texture_set_texture (stex, NULL);
+  meta_shaped_texture_set_textures (stex, NULL, NULL);
   cogl_flush ();
 
   meta_x11_error_trap_push (display->x11_display);
@@ -105,6 +109,7 @@ detach_pixmap (MetaSurfaceActorX11 *self)
   meta_x11_error_trap_pop (display->x11_display);
 
   g_clear_pointer (&self->texture, cogl_object_unref);
+  g_clear_pointer (&self->texture_right, cogl_object_unref);
 }
 
 static void
@@ -114,23 +119,37 @@ set_pixmap (MetaSurfaceActorX11 *self,
   CoglContext *ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
   MetaShapedTexture *stex = meta_surface_actor_get_texture (META_SURFACE_ACTOR (self));
   CoglError *error = NULL;
-  CoglTexture *texture;
+  CoglTexturePixmapX11 *texture;
+  CoglTexturePixmapX11 *texture_right;
 
   g_assert (self->pixmap == None);
   self->pixmap = pixmap;
 
-  texture = COGL_TEXTURE (cogl_texture_pixmap_x11_new (ctx, self->pixmap, FALSE, &error));
+  if (self->stereo)
+    texture = cogl_texture_pixmap_x11_new_left (ctx, pixmap, FALSE, &error);
+  else
+    texture = cogl_texture_pixmap_x11_new (ctx, pixmap, FALSE, &error);
+
+  if (self->stereo)
+    texture_right = cogl_texture_pixmap_x11_new_right (texture);
+  else
+    texture_right = NULL;
 
   if (error != NULL)
     {
       g_warning ("Failed to allocate stex texture: %s", error->message);
       cogl_error_free (error);
     }
-  else if (G_UNLIKELY (!cogl_texture_pixmap_x11_is_using_tfp_extension (COGL_TEXTURE_PIXMAP_X11 (texture))))
+  else if (G_UNLIKELY (!cogl_texture_pixmap_x11_is_using_tfp_extension (texture)))
     g_warning ("NOTE: Not using GLX TFP!\n");
 
-  self->texture = texture;
-  meta_shaped_texture_set_texture (stex, texture);
+  self->texture = COGL_TEXTURE (texture);
+  if (self->stereo)
+    self->texture_right = COGL_TEXTURE (texture_right);
+
+  meta_shaped_texture_set_textures (stex,
+                                    COGL_TEXTURE (texture),
+                                    COGL_TEXTURE (texture_right));;
 }
 
 static void
@@ -419,8 +438,8 @@ reset_texture (MetaSurfaceActorX11 *self)
   /* Setting the texture to NULL will cause all the FBO's cached by the
    * shaped texture's MetaTextureTower to be discarded and recreated.
    */
-  meta_shaped_texture_set_texture (stex, NULL);
-  meta_shaped_texture_set_texture (stex, self->texture);
+  meta_shaped_texture_set_textures (stex, NULL, NULL);
+  meta_shaped_texture_set_textures (stex, self->texture, self->texture_right);
 }
 
 MetaSurfaceActor *
@@ -428,12 +447,17 @@ meta_surface_actor_x11_new (MetaWindow *window)
 {
   MetaSurfaceActorX11 *self = g_object_new (META_TYPE_SURFACE_ACTOR_X11, NULL);
   MetaDisplay *display = meta_window_get_display (window);
+  Window xwindow;
 
   g_assert (!meta_is_wayland_compositor ());
 
   self->window = window;
   self->display = display;
 
+  xwindow = meta_window_x11_get_toplevel_xwindow (window);
+  self->stereo = meta_compositor_window_is_stereo (display, xwindow);
+  meta_compositor_select_stereo_notify (display, xwindow);
+
   g_signal_connect_object (self->display, "gl-video-memory-purged",
                            G_CALLBACK (reset_texture), self, G_CONNECT_SWAPPED);
 
@@ -463,3 +487,17 @@ meta_surface_actor_x11_set_size (MetaSurfaceActorX11 *self,
   self->last_height = height;
   meta_shaped_texture_set_fallback_size (stex, width, height);
 }
+
+void
+meta_surface_actor_x11_stereo_notify (MetaSurfaceActorX11 *self,
+                                      gboolean             stereo_tree)
+{
+  self->stereo = stereo_tree != FALSE;
+  detach_pixmap (self);
+}
+
+gboolean
+meta_surface_actor_x11_is_stereo (MetaSurfaceActorX11 *self)
+{
+  return self->stereo;
+}
diff --git a/src/compositor/meta-surface-actor-x11.h b/src/compositor/meta-surface-actor-x11.h
index 2c4ed4dd6..3bdd5fdb0 100644
--- a/src/compositor/meta-surface-actor-x11.h
+++ b/src/compositor/meta-surface-actor-x11.h
@@ -47,6 +47,11 @@ MetaSurfaceActor * meta_surface_actor_x11_new (MetaWindow *window);
 void meta_surface_actor_x11_set_size (MetaSurfaceActorX11 *self,
                                       int width, int height);
 
+void meta_surface_actor_x11_stereo_notify (MetaSurfaceActorX11 *self,
+                                           gboolean             stereo_tree);
+
+gboolean meta_surface_actor_x11_is_stereo (MetaSurfaceActorX11 *self);
+
 G_END_DECLS
 
 #endif /* __META_SURFACE_ACTOR_X11_H__ */
diff --git a/src/compositor/meta-window-actor-private.h b/src/compositor/meta-window-actor-private.h
index 6333f43db..9c1c12d09 100644
--- a/src/compositor/meta-window-actor-private.h
+++ b/src/compositor/meta-window-actor-private.h
@@ -76,4 +76,9 @@ MetaSurfaceActor *meta_window_actor_get_surface (MetaWindowActor *self);
 void meta_window_actor_update_surface (MetaWindowActor *self);
 MetaWindowActor *meta_window_actor_from_window (MetaWindow *window);
 
+void meta_window_actor_stereo_notify (MetaWindowActor *actor,
+                                      gboolean         stereo_tree);
+
+gboolean meta_window_actor_is_stereo (MetaWindowActor *actor);
+
 #endif /* META_WINDOW_ACTOR_PRIVATE_H */
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 1c8dc8fe5..11686d00b 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -2031,3 +2031,25 @@ screen_cast_window_iface_init (MetaScreenCastWindowInterface *iface)
   iface->capture_into = meta_window_actor_capture_into;
   iface->has_damage = meta_window_actor_has_damage;
 }
+
+void
+meta_window_actor_stereo_notify (MetaWindowActor *self,
+                                 gboolean         stereo_tree)
+{
+  MetaWindowActorPrivate *priv = meta_window_actor_get_instance_private (self);
+
+  if (META_IS_SURFACE_ACTOR_X11 (priv->surface))
+    meta_surface_actor_x11_stereo_notify (META_SURFACE_ACTOR_X11 (priv->surface),
+                                          stereo_tree);
+}
+
+gboolean
+meta_window_actor_is_stereo (MetaWindowActor *self)
+{
+  MetaWindowActorPrivate *priv = meta_window_actor_get_instance_private (self);
+
+  if (META_IS_SURFACE_ACTOR_X11 (priv->surface))
+    return meta_surface_actor_x11_is_stereo (META_SURFACE_ACTOR_X11 (priv->surface));
+  else
+    return FALSE;
+}
diff --git a/src/core/main.c b/src/core/main.c
index e8464720f..629f8e94e 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -81,6 +81,7 @@
 #include "meta/meta-backend.h"
 #include "meta/meta-x11-errors.h"
 #include "meta/prefs.h"
+#include "stereo.h"
 #include "ui/ui.h"
 #include "x11/session.h"
 
@@ -589,6 +590,9 @@ meta_init (void)
 
   meta_init_backend (backend_gtype);
 
+  if (!meta_is_wayland_compositor ())
+    meta_stereo_init ();
+
   meta_clutter_init ();
 
 #ifdef HAVE_WAYLAND
diff --git a/src/core/stereo.c b/src/core/stereo.c
new file mode 100644
index 000000000..817056527
--- /dev/null
+++ b/src/core/stereo.c
@@ -0,0 +1,154 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2014 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * SECTION:stereo
+ * @short_description: Keep track of whether we are a stereo compositor
+ *
+ * With GLX, we need to use a different GL context for stereo and
+ * non-stereo support. Support for multiple GL contexts is unfinished
+ * in Cogl and entirely lacking in Clutter, so it's by far easier
+ * to just restart Mutter when we detect a stereo window.
+ *
+ * A property _MUTTER_ENABLE_STEREO is maintained on the root window
+ * to know whether we should initialize clutter for stereo or not.
+ * When the presence or absence of stereo windows mismatches the
+ * stereo-enabled state for a sufficiently long period of time,
+ * we restart Mutter.
+ */
+
+#include <config.h>
+
+#include <clutter/x11/clutter-x11.h>
+#include <gio/gunixinputstream.h>
+#include <X11/Xatom.h>
+
+#include "display-private.h"
+#include <meta/main.h>
+#include <meta/meta-x11-display.h>
+#include <meta/util.h>
+#include "stereo.h"
+#include "ui/ui.h"
+#include "util-private.h"
+
+static guint stereo_switch_id = 0;
+static gboolean stereo_enabled = FALSE;
+/* -1 so the first time meta_stereo_set_have_stereo_windows() is called
+ * we avoid the short-circuit and set up a timeout to restart
+ * if necessary */
+static gboolean stereo_have_windows = (gboolean)-1;
+static gboolean stereo_restart = FALSE;
+
+#define STEREO_ENABLE_WAIT 1000
+#define STEREO_DISABLE_WAIT 5000
+
+void
+meta_stereo_init (void)
+{
+  Display *xdisplay;
+  Window root;
+  Atom atom_enable_stereo;
+  Atom type;
+  int format;
+  unsigned long n_items, bytes_after;
+  guchar *data;
+
+  xdisplay = XOpenDisplay (NULL);
+  if (xdisplay == NULL)
+    meta_fatal ("Unable to open X display %s\n", XDisplayName (NULL));
+
+  root = DefaultRootWindow (xdisplay);
+  atom_enable_stereo = XInternAtom (xdisplay, "_MUTTER_ENABLE_STEREO", False);
+
+  XGetWindowProperty (xdisplay, root, atom_enable_stereo,
+                      0, 1, False, XA_INTEGER,
+                      &type, &format, &n_items, &bytes_after, &data);
+  if (type == XA_INTEGER)
+    {
+      if (format == 32 && n_items == 1 && bytes_after == 0)
+        {
+          stereo_enabled = *(long *)data;
+        }
+      else
+        {
+          meta_warning ("Bad value for _MUTTER_ENABLE_STEREO property\n");
+        }
+
+      XFree (data);
+    }
+  else if (type != None)
+    {
+      meta_warning ("Bad type for _MUTTER_ENABLE_STEREO property\n");
+    }
+
+  meta_verbose ("On startup, _MUTTER_ENABLE_STEREO=%s",
+                stereo_enabled ? "yes" : "no");
+  clutter_x11_set_use_stereo_stage (stereo_enabled);
+  XCloseDisplay (xdisplay);
+}
+
+static gboolean
+meta_stereo_switch (gpointer data)
+{
+  stereo_switch_id = 0;
+  stereo_restart = TRUE;
+
+  meta_restart (stereo_have_windows ?
+                _("Enabling stereo...") :
+                _("Disabling stereo..."));
+
+  return FALSE;
+}
+
+void
+meta_stereo_set_have_stereo_windows (gboolean have_windows)
+{
+  have_windows = have_windows != FALSE;
+
+  if (!stereo_restart && have_windows != stereo_have_windows)
+    {
+      MetaDisplay *display = meta_get_display ();
+      Display *xdisplay = meta_x11_display_get_xdisplay (display->x11_display);
+      Window root = DefaultRootWindow (xdisplay);
+      Atom atom_enable_stereo = XInternAtom (xdisplay, "_MUTTER_ENABLE_STEREO", False);
+      long value;
+
+      stereo_have_windows = have_windows;
+
+      if (stereo_have_windows)
+        meta_verbose ("Detected stereo windows\n");
+      else
+        meta_verbose ("No stereo windows detected\n");
+
+      value = stereo_have_windows;
+      XChangeProperty (xdisplay, root,
+                       atom_enable_stereo, XA_INTEGER, 32,
+                       PropModeReplace, (guchar *)&value, 1);
+
+      if (stereo_switch_id != 0)
+        {
+          g_source_remove (stereo_switch_id);
+          stereo_switch_id = 0;
+        }
+
+      if (stereo_have_windows != stereo_enabled)
+        stereo_switch_id = g_timeout_add (stereo_have_windows ? STEREO_ENABLE_WAIT : STEREO_DISABLE_WAIT,
+                                          meta_stereo_switch, NULL);
+    }
+}
diff --git a/src/core/stereo.h b/src/core/stereo.h
new file mode 100644
index 000000000..ccd1d702a
--- /dev/null
+++ b/src/core/stereo.h
@@ -0,0 +1,28 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2014 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef META_STEREO_H
+#define META_STEREO_H
+
+void     meta_stereo_init                    (void);
+void     meta_stereo_set_have_stereo_windows (gboolean have_windows);
+gboolean meta_stereo_is_restart              (void);
+void     meta_stereo_finish_restart          (void);
+
+#endif
diff --git a/src/meson.build b/src/meson.build
index 9919b5cfb..7cced8f53 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -353,6 +353,8 @@ mutter_sources = [
   'core/stack.h',
   'core/stack-tracker.c',
   'core/stack-tracker.h',
+  'core/stereo.c',
+  'core/stereo.h',
   'core/startup-notification.c',
   'core/startup-notification-private.h',
   'core/util.c',
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index da0acfcbb..ddad1a45c 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -731,7 +731,7 @@ meta_wayland_surface_apply_pending_state (MetaWaylandSurface      *surface,
               snippet = meta_wayland_buffer_create_snippet (pending->buffer);
               is_y_inverted = meta_wayland_buffer_is_y_inverted (pending->buffer);
 
-              meta_shaped_texture_set_texture (stex, texture);
+              meta_shaped_texture_set_textures (stex, texture, NULL);
               meta_shaped_texture_set_snippet (stex, snippet);
               meta_shaped_texture_set_is_y_inverted (stex, is_y_inverted);
               g_clear_pointer (&snippet, cogl_object_unref);
-- 
2.28.0