wayland: Add support for EGLStream client buffers

This commit adds for a new type of buffer being attached to a Wayland
surface: buffers from an EGLStream. These buffers behave very
differently from regular Wayland buffers; instead of each buffer
reperesenting an actual frame, the same buffer is attached over and
over again, and EGL API is used to switch the content of the OpenGL
texture associated with the buffer attached. It more or less
side-tracks the Wayland buffer handling.

It is implemented by creating a MetaWaylandEglStream object, dealing
with the EGLStream state. The lifetime of the MetaWaylandEglStream is
tied to the texture object (CoglTexture), which is referenced-counted
and owned by both the actors and the MetaWaylandBuffer.

When the buffer is reattached and committed, the EGLStream is triggered
to switch the content of the associated texture to the new content.
This means that one cannot keep old texture content around without
copying, so any feature relying on that will effectively be broken.

https://bugzilla.gnome.org/show_bug.cgi?id=773629

src/Makefile.am

@@ -293,6 +293,8 @@ libmutter_la_SOURCES +=				\
 	wayland/meta-wayland-data-device.c      \
 	wayland/meta-wayland-data-device.h      \
 	wayland/meta-wayland-data-device-private.h	\
+	wayland/meta-wayland-egl-stream.c	\
+	wayland/meta-wayland-egl-stream.h	\
 	wayland/meta-wayland-input-device.c	\
 	wayland/meta-wayland-input-device.h	\
 	wayland/meta-wayland-pointer-gestures.c	\

src/backends/native/meta-renderer-native.c

@@ -846,6 +846,12 @@ static gboolean
 meta_renderer_native_init_egl_context (CoglContext *cogl_context,
                                        GError     **error)
 {
+#ifdef HAVE_EGL_DEVICE
+  CoglRenderer *cogl_renderer = cogl_context->display->renderer;
+  CoglRendererEGL *egl_renderer = cogl_renderer->winsys;
+  MetaRendererNative *renderer_native = egl_renderer->platform;
+#endif
+
   COGL_FLAGS_SET (cogl_context->features,
                   COGL_FEATURE_ID_SWAP_BUFFERS_EVENT, TRUE);
   /* TODO: remove this deprecated feature */
@@ -859,6 +865,12 @@ meta_renderer_native_init_egl_context (CoglContext *cogl_context,
                   COGL_WINSYS_FEATURE_MULTIPLE_ONSCREEN,
                   TRUE);
 
+#ifdef HAVE_EGL_DEVICE
+  if (renderer_native->mode == META_RENDERER_NATIVE_MODE_EGL_DEVICE)
+    COGL_FLAGS_SET (cogl_context->features,
+                    COGL_FEATURE_ID_TEXTURE_EGL_IMAGE_EXTERNAL, TRUE);
+#endif
+
   return TRUE;
 }
 

src/wayland/meta-wayland-buffer.c

@@ -86,6 +86,7 @@ typedef enum _MetaWaylandBufferType
   META_WAYLAND_BUFFER_TYPE_UNKNOWN,
   META_WAYLAND_BUFFER_TYPE_SHM,
   META_WAYLAND_BUFFER_TYPE_EGL_IMAGE,
+  META_WAYLAND_BUFFER_TYPE_EGL_STREAM,
 } MetaWaylandBufferType;
 
 static MetaWaylandBufferType
@@ -107,6 +108,9 @@ determine_buffer_type (MetaWaylandBuffer *buffer)
                                      NULL))
     return META_WAYLAND_BUFFER_TYPE_EGL_IMAGE;
 
+  if (meta_wayland_is_egl_stream_buffer (buffer))
+    return META_WAYLAND_BUFFER_TYPE_EGL_STREAM;
+
   return META_WAYLAND_BUFFER_TYPE_UNKNOWN;
 }
 
@@ -276,6 +280,39 @@ egl_image_buffer_attach (MetaWaylandBuffer *buffer,
   return TRUE;
 }
 
+static gboolean
+egl_stream_buffer_attach (MetaWaylandBuffer  *buffer,
+                          GError            **error)
+{
+  MetaWaylandEglStream *stream;
+
+  stream = buffer->egl_stream.stream;
+  if (!stream)
+    stream = meta_wayland_egl_stream_new (buffer, error);
+
+  if (!stream)
+    return FALSE;
+
+  buffer->egl_stream.stream = stream;
+
+  if (!buffer->texture)
+    {
+      CoglTexture2D *texture;
+
+      texture = meta_wayland_egl_stream_create_texture (stream, error);
+      if (!texture)
+        return FALSE;
+
+      buffer->texture = COGL_TEXTURE (texture);
+      buffer->is_y_inverted = meta_wayland_egl_stream_is_y_inverted (stream);
+    }
+
+  if (!meta_wayland_egl_stream_attach (stream, error))
+    return FALSE;
+
+  return TRUE;
+}
+
 gboolean
 meta_wayland_buffer_attach (MetaWaylandBuffer *buffer,
                             GError           **error)
@@ -292,6 +329,9 @@ meta_wayland_buffer_attach (MetaWaylandBuffer *buffer,
       return shm_buffer_attach (buffer, error);
     case META_WAYLAND_BUFFER_TYPE_EGL_IMAGE:
       return egl_image_buffer_attach (buffer, error);
+    case META_WAYLAND_BUFFER_TYPE_EGL_STREAM:
+      return egl_stream_buffer_attach (buffer, error);
+      break;
     case META_WAYLAND_BUFFER_TYPE_UNKNOWN:
       g_set_error (error, G_IO_ERROR,
                    G_IO_ERROR_FAILED,
@@ -308,6 +348,15 @@ meta_wayland_buffer_get_texture (MetaWaylandBuffer *buffer)
   return buffer->texture;
 }
 
+CoglSnippet *
+meta_wayland_buffer_create_snippet (MetaWaylandBuffer *buffer)
+{
+  if (!buffer->egl_stream.stream)
+    return NULL;
+
+  return meta_wayland_egl_stream_create_snippet ();
+}
+
 gboolean
 meta_wayland_buffer_is_y_inverted (MetaWaylandBuffer *buffer)
 {
@@ -376,6 +425,7 @@ meta_wayland_buffer_process_damage (MetaWaylandBuffer *buffer,
     case META_WAYLAND_BUFFER_TYPE_SHM:
       res = process_shm_buffer_damage (buffer, region, &error);
     case META_WAYLAND_BUFFER_TYPE_EGL_IMAGE:
+    case META_WAYLAND_BUFFER_TYPE_EGL_STREAM:
       res = TRUE;
       break;
     case META_WAYLAND_BUFFER_TYPE_UNKNOWN:
@@ -398,6 +448,7 @@ meta_wayland_buffer_finalize (GObject *object)
   MetaWaylandBuffer *buffer = META_WAYLAND_BUFFER (object);
 
   g_clear_pointer (&buffer->texture, cogl_object_unref);
+  g_clear_object (&buffer->egl_stream.stream);
 
   G_OBJECT_CLASS (meta_wayland_buffer_parent_class)->finalize (object);
 }

src/wayland/meta-wayland-buffer.h

@@ -30,6 +30,7 @@
 #include <wayland-server.h>
 
 #include "meta-wayland-types.h"
+#include "meta-wayland-egl-stream.h"
 
 struct _MetaWaylandBuffer
 {
@@ -40,6 +41,10 @@ struct _MetaWaylandBuffer
 
   CoglTexture *texture;
   gboolean is_y_inverted;
+
+  struct {
+    MetaWaylandEglStream *stream;
+  } egl_stream;
 };
 
 #define META_TYPE_WAYLAND_BUFFER (meta_wayland_buffer_get_type ())
@@ -50,6 +55,7 @@ MetaWaylandBuffer *     meta_wayland_buffer_from_resource       (struct wl_resou
 gboolean                meta_wayland_buffer_attach              (MetaWaylandBuffer     *buffer,
                                                                  GError               **error);
 CoglTexture *           meta_wayland_buffer_get_texture         (MetaWaylandBuffer     *buffer);
+CoglSnippet *           meta_wayland_buffer_create_snippet      (MetaWaylandBuffer     *buffer);
 gboolean                meta_wayland_buffer_is_y_inverted       (MetaWaylandBuffer     *buffer);
 void                    meta_wayland_buffer_process_damage      (MetaWaylandBuffer     *buffer,
                                                                  cairo_region_t        *region);

src/wayland/meta-wayland-egl-stream.c

@@ -0,0 +1,279 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2016 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#include "config.h"
+
+#include "wayland/meta-wayland-egl-stream.h"
+
+#include "cogl/cogl-egl.h"
+#include "backends/meta-backend-private.h"
+#include "backends/meta-egl.h"
+#include "meta/meta-backend.h"
+#include "wayland/meta-wayland-buffer.h"
+
+struct _MetaWaylandEglStream
+{
+  GObject parent;
+
+  EGLStreamKHR egl_stream;
+  MetaWaylandBuffer *buffer;
+  CoglTexture2D *texture;
+  gboolean is_y_inverted;
+};
+
+G_DEFINE_TYPE (MetaWaylandEglStream, meta_wayland_egl_stream,
+               G_TYPE_OBJECT)
+
+MetaWaylandEglStream *
+meta_wayland_egl_stream_new (MetaWaylandBuffer *buffer,
+                             GError           **error)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+  g_autoptr (MetaWaylandEglStream) stream = NULL;
+  int stream_fd;
+  EGLStreamKHR egl_stream;
+
+  stream = g_object_new (META_TYPE_WAYLAND_EGL_STREAM, NULL);
+
+  /*
+   * HACK: Use a (as far as I can tell) undocumented hack by passing
+   * EGL_WAYLAND_BUFFER_WL to eglQueryWaylandBufferWL. If it happens to be a
+   * dummy EGLStream buffer, we'll get a EGLStream file descriptor.
+   *
+   * FIXME: At some point, replace this with the EGL_WL_wayland_eglstream
+   * extension.
+   */
+  if (!meta_egl_query_wayland_buffer (egl, egl_display, buffer->resource,
+                                      EGL_WAYLAND_BUFFER_WL, &stream_fd,
+                                      error))
+    return NULL;
+
+  if (stream_fd == EGL_NO_FILE_DESCRIPTOR_KHR)
+    {
+      g_set_error (error, G_IO_ERROR,
+                   G_IO_ERROR_FAILED,
+                   "Stream already used with other wl_buffer");
+      return NULL;
+    }
+
+  egl_stream = meta_egl_create_stream_from_file_descriptor (egl, egl_display, stream_fd,
+                                                            error);
+  close (stream_fd);
+  if (egl_stream == EGL_NO_STREAM_KHR)
+    return NULL;
+
+  stream->egl_stream = egl_stream;
+  stream->buffer = buffer;
+
+  return g_steal_pointer (&stream);
+}
+
+static void
+stream_texture_destroyed (gpointer data)
+{
+  MetaWaylandEglStream *stream = data;
+
+  stream->texture = NULL;
+
+  g_object_unref (stream);
+}
+
+static gboolean
+alloc_egl_stream_texture (CoglTexture2D *texture,
+                          gpointer       user_data,
+                          GError       **error)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+  MetaWaylandEglStream *stream = user_data;
+
+  return meta_egl_stream_consumer_gl_texture_external (egl, egl_display,
+                                                       stream->egl_stream,
+                                                       error);
+}
+
+CoglTexture2D *
+meta_wayland_egl_stream_create_texture (MetaWaylandEglStream *stream,
+                                        GError              **error)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+  CoglTexture2D *texture;
+  int width, height;
+  int y_inverted;
+
+  if (!meta_egl_query_wayland_buffer (egl, egl_display,
+                                      stream->buffer->resource,
+                                      EGL_WIDTH, &width,
+                                      error))
+    return NULL;
+
+  if (!meta_egl_query_wayland_buffer (egl, egl_display,
+                                      stream->buffer->resource,
+                                      EGL_HEIGHT, &height,
+                                      error))
+    return NULL;
+
+  if (!meta_egl_query_wayland_buffer (egl, egl_display,
+                                      stream->buffer->resource,
+                                      EGL_WAYLAND_Y_INVERTED_WL, &y_inverted,
+                                      NULL))
+    y_inverted = EGL_TRUE;
+
+  texture =
+    cogl_texture_2d_new_from_egl_image_external (cogl_context,
+                                                 width, height,
+                                                 alloc_egl_stream_texture,
+                                                 g_object_ref (stream),
+                                                 stream_texture_destroyed,
+                                                 error);
+  if (!texture)
+    {
+      g_object_unref (stream);
+      return NULL;
+    }
+
+  if (!cogl_texture_allocate (COGL_TEXTURE (texture), error))
+    {
+      cogl_object_unref (texture);
+      return NULL;
+    }
+
+  stream->texture = texture;
+  stream->is_y_inverted = !!y_inverted;
+
+  return texture;
+}
+
+gboolean
+meta_wayland_egl_stream_attach (MetaWaylandEglStream *stream,
+                                GError              **error)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+  EGLint stream_state;
+
+  if (!meta_egl_query_stream (egl, egl_display, stream->egl_stream,
+                              EGL_STREAM_STATE_KHR, &stream_state,
+                              error))
+    return FALSE;
+
+  if (stream_state == EGL_STREAM_STATE_NEW_FRAME_AVAILABLE_KHR)
+    {
+      if (!meta_egl_stream_consumer_acquire (egl, egl_display,
+                                             stream->egl_stream,
+                                             error))
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
+meta_wayland_egl_stream_is_y_inverted (MetaWaylandEglStream *stream)
+{
+  return stream->is_y_inverted;
+}
+
+CoglSnippet *
+meta_wayland_egl_stream_create_snippet (void)
+{
+  CoglSnippet *snippet;
+
+  snippet = cogl_snippet_new (COGL_SNIPPET_HOOK_TEXTURE_LOOKUP,
+                              "uniform samplerExternalOES tex_external;",
+                              NULL);
+  cogl_snippet_set_replace (snippet,
+                            "cogl_texel = texture2D (tex_external,\n"
+                            "                        cogl_tex_coord.xy);");
+
+  return snippet;
+}
+
+gboolean
+meta_wayland_is_egl_stream_buffer (MetaWaylandBuffer *buffer)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+  int stream_fd;
+
+  if (!meta_egl_has_extensions (egl, egl_display, NULL,
+                                "EGL_KHR_stream_consumer_gltexture",
+                                "EGL_KHR_stream_cross_process_fd",
+                                NULL))
+    return FALSE;
+
+  if (!meta_egl_query_wayland_buffer (egl, egl_display, buffer->resource,
+                                      EGL_WAYLAND_BUFFER_WL, &stream_fd,
+                                      NULL))
+    return FALSE;
+
+  return TRUE;
+}
+
+static void
+meta_wayland_egl_stream_finalize (GObject *object)
+{
+  MetaWaylandEglStream *stream = META_WAYLAND_EGL_STREAM (object);
+  MetaBackend *backend = meta_get_backend ();
+  MetaEgl *egl = meta_backend_get_egl (backend);
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+  CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  EGLDisplay egl_display = cogl_egl_context_get_egl_display (cogl_context);
+
+  g_assert (!stream->texture);
+
+  meta_egl_destroy_stream (egl, egl_display, stream->egl_stream, NULL);
+
+  G_OBJECT_CLASS (meta_wayland_egl_stream_parent_class)->finalize (object);
+}
+
+static void
+meta_wayland_egl_stream_init (MetaWaylandEglStream *stream)
+{
+}
+
+static void
+meta_wayland_egl_stream_class_init (MetaWaylandEglStreamClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = meta_wayland_egl_stream_finalize;
+}

src/wayland/meta-wayland-egl-stream.h

@@ -0,0 +1,52 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2016 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#ifndef META_WAYLAND_EGL_STREAM_H
+#define META_WAYLAND_EGL_STREAM_H
+
+#include <glib.h>
+#include <glib-object.h>
+
+#include "cogl/cogl/cogl.h"
+#include "wayland/meta-wayland-types.h"
+
+#define META_TYPE_WAYLAND_EGL_STREAM (meta_wayland_egl_stream_get_type ())
+G_DECLARE_FINAL_TYPE (MetaWaylandEglStream, meta_wayland_egl_stream,
+                      META, WAYLAND_EGL_STREAM, GObject);
+
+gboolean meta_wayland_is_egl_stream_buffer (MetaWaylandBuffer *buffer);
+
+MetaWaylandEglStream * meta_wayland_egl_stream_new (MetaWaylandBuffer *buffer,
+                                                    GError           **error);
+
+gboolean meta_wayland_egl_stream_attach (MetaWaylandEglStream *stream,
+                                         GError              **error);
+
+CoglTexture2D * meta_wayland_egl_stream_create_texture (MetaWaylandEglStream *stream,
+                                                        GError              **error);
+CoglSnippet * meta_wayland_egl_stream_create_snippet (void);
+
+gboolean meta_wayland_egl_stream_is_y_inverted (MetaWaylandEglStream *stream);
+
+#endif /* META_WAYLAND_EGL_STREAM_H */

src/wayland/meta-wayland-surface.c

@@ -755,14 +755,18 @@ apply_pending_state (MetaWaylandSurface      *surface,
             {
               MetaShapedTexture *stex;
               CoglTexture *texture;
+              CoglSnippet *snippet;
               gboolean is_y_inverted;
 
               stex = meta_surface_actor_get_texture (surface->surface_actor);
               texture = meta_wayland_buffer_get_texture (pending->buffer);
+              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_snippet (stex, snippet);
               meta_shaped_texture_set_is_y_inverted (stex, is_y_inverted);
+              g_clear_pointer (&snippet, cogl_object_unref);
             }
         }