From db5c011da1f3d8b233af17d104b6fecfc0d7d716 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20Johan=20S=C3=B8rvig?= <morten.sorvig@digia.com>
Date: Tue, 3 Feb 2015 12:40:49 +0100
Subject: [PATCH] Cocoa: Improve QT_MAC_WANTS_LAYER for GL windows

Add the NSOpenGLPFANoRecovery pixel format attribute.

This disables the software rendering fallback and
makes compositing OpenGL and raster NSViews using
Core Animation layers possible.

With QT_MAC_WANTS_LAYER enabled, native NSViews now
stack correctly with QWindows with OpenGL content.

One known limitation is that this mode currently
supports main-thread rendering only.

Change-Id: I2060cceda846b305b33b47f2eba3cb7cb838039c
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>
---
 src/platformsupport/cglconvenience/cglconvenience.mm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/platformsupport/cglconvenience/cglconvenience.mm b/src/platformsupport/cglconvenience/cglconvenience.mm
index c5f09f15ec..d0663078f5 100644
--- a/src/platformsupport/cglconvenience/cglconvenience.mm
+++ b/src/platformsupport/cglconvenience/cglconvenience.mm
@@ -32,6 +32,7 @@
 ****************************************************************************/
 
 #include "cglconvenience_p.h"
+#include <QtCore/qglobal.h>
 #include <QtCore/private/qcore_mac_p.h>
 #include <Cocoa/Cocoa.h>
 #include <QVector>
@@ -125,6 +126,14 @@ void *qcgl_createNSOpenGLPixelFormat(const QSurfaceFormat &format)
         attrs << NSOpenGLPFAStereo;
 
     attrs << NSOpenGLPFAAllowOfflineRenderers;
+
+    QByteArray useLayer = qgetenv("QT_MAC_WANTS_LAYER");
+    if (!useLayer.isEmpty() && useLayer.toInt() > 0) {
+        // Disable the software rendering fallback. This makes compositing
+        // OpenGL and raster NSViews using Core Animation layers possible.
+        attrs << NSOpenGLPFANoRecovery;
+    }
+
     attrs << 0;
 
     NSOpenGLPixelFormat* pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs.constData()];