From 7bcc274dbc6cb75814cce3e5c2e7f45cf25b0538 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Tue, 9 Feb 2021 17:59:08 +0100
Subject: [PATCH 1/2] clutter/stage-view: Hide double buffered shadowfb behind
 envvar

It still results in worse performance than a single FBO based shadowfb,
so don't use it. It will need a new EGL extension for zero copy CPU
memory based FBO to be feasable.
---
 clutter/clutter/clutter-stage-view.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/clutter/clutter/clutter-stage-view.c b/clutter/clutter/clutter-stage-view.c
index 5e5966d06..ec18db7b8 100644
--- a/clutter/clutter/clutter-stage-view.c
+++ b/clutter/clutter/clutter-stage-view.c
@@ -282,6 +282,14 @@ init_dma_buf_shadowfbs (ClutterStageView  *view,
   CoglRenderer *cogl_renderer = cogl_context_get_renderer (cogl_context);
   CoglFramebuffer *initial_shadowfb;
 
+  if (g_strcmp0 (g_getenv ("MUTTER_DEBUG_ENABLE_DOUBLE_BUFFER_SHADOWFB"),
+                 "1") != 0)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Double buffered shadowfb not enabled");
+      return FALSE;
+    }
+
   if (!cogl_clutter_winsys_has_feature (COGL_WINSYS_FEATURE_BUFFER_AGE))
     {
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
@@ -390,8 +398,8 @@ init_shadowfb (ClutterStageView *view)
       return;
     }
 
-  g_warning ("Failed to initialize double buffered shadow fb for %s: %s",
-             priv->name, error->message);
+  g_debug ("Failed to initialize double buffered shadow fb for %s: %s",
+           priv->name, error->message);
   g_clear_error (&error);
 
   if (!init_fallback_shadowfb (view, cogl_context, width, height, &error))
-- 
2.29.2