[mutter: 12/13] backends/native: Set offscreen on the transformed MetaRendererViews

[Carlos Garnacho <carlosg src gnome org>]

commit 9e641f623fd917f7c795f0c07c64a7627923f566
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Aug 1 03:48:30 2016 +0200

    backends/native: Set offscreen on the transformed MetaRendererViews
    
    The texture is only created if the view is transformed at the software level,
    otherwise the texture is NULL, and rendering happens on the onscreen.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745079

 src/backends/native/meta-renderer-native.c |   57 ++++++++++++++++++++++++++++
 1 files changed, 57 insertions(+), 0 deletions(-)
---
diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
index 9867a5b..2093e09 100644
--- a/src/backends/native/meta-renderer-native.c
+++ b/src/backends/native/meta-renderer-native.c
@@ -885,6 +885,39 @@ meta_renderer_native_create_onscreen (MetaRendererNative    *renderer,
   return onscreen;
 }
 
+static CoglOffscreen *
+meta_renderer_native_create_offscreen (MetaRendererNative    *renderer,
+                                       CoglContext           *context,
+                                       MetaMonitorTransform   transform,
+                                       gint                   view_width,
+                                       gint                   view_height)
+{
+  CoglOffscreen *fb;
+  CoglTexture2D *tex;
+  GError *error = NULL;
+
+  tex = cogl_texture_2d_new_with_size (context, view_width, view_height);
+  cogl_primitive_texture_set_auto_mipmap (COGL_PRIMITIVE_TEXTURE (tex), FALSE);
+
+  if (!cogl_texture_allocate (COGL_TEXTURE (tex), &error))
+    {
+      cogl_object_unref (tex);
+      return FALSE;
+    }
+
+  fb = cogl_offscreen_new_with_texture (COGL_TEXTURE (tex));
+  cogl_object_unref (tex);
+  if (!cogl_framebuffer_allocate (COGL_FRAMEBUFFER (fb), &error))
+    {
+      g_warning ("Could not create offscreen: %s", error->message);
+      g_error_free (error);
+      cogl_object_unref (fb);
+      return FALSE;
+    }
+
+  return fb;
+}
+
 gboolean
 meta_renderer_native_set_legacy_view_size (MetaRendererNative *renderer_native,
                                            MetaRendererView   *view,
@@ -1083,8 +1116,12 @@ meta_renderer_native_create_view (MetaRenderer    *renderer,
   MetaBackend *backend = meta_get_backend ();
   ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
   CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
+  CoglDisplay *cogl_display = cogl_context_get_display (cogl_context);
+  CoglDisplayEGL *egl_display = cogl_display->winsys;
+  CoglOnscreenEGL *egl_onscreen;
   MetaMonitorTransform transform;
   CoglOnscreen *onscreen = NULL;
+  CoglOffscreen *offscreen = NULL;
   MetaRendererView *view;
 
   transform = meta_renderer_native_get_monitor_info_transform (renderer,
@@ -1098,13 +1135,33 @@ meta_renderer_native_create_view (MetaRenderer    *renderer,
   if (!onscreen)
     meta_fatal ("Failed to allocate onscreen framebuffer\n");
 
+  /* Ensure we don't point to stale surfaces when creating the offscreen */
+  egl_onscreen = onscreen->winsys;
+  _cogl_winsys_egl_make_current (cogl_display,
+                                 egl_onscreen->egl_surface,
+                                 egl_onscreen->egl_surface,
+                                 egl_display->egl_context);
+
+  if (transform != META_MONITOR_TRANSFORM_NORMAL)
+    {
+      offscreen = meta_renderer_native_create_offscreen (META_RENDERER_NATIVE (renderer),
+                                                         cogl_context,
+                                                         transform,
+                                                         monitor_info->rect.width,
+                                                         monitor_info->rect.height);
+      if (!offscreen)
+        meta_fatal ("Failed to allocate back buffer texture\n");
+    }
+
   view = g_object_new (META_TYPE_RENDERER_VIEW,
                        "layout", &monitor_info->rect,
                        "framebuffer", onscreen,
+                       "offscreen", offscreen,
                        "monitor-info", monitor_info,
                        "transform", transform,
                        NULL);
   cogl_object_unref (onscreen);
+  g_clear_pointer (&offscreen, cogl_object_unref);
 
   meta_onscreen_native_set_view (onscreen, view);