Support adapting an existing NSOpenGLContext in cocoa

Change-Id: I61b4055020c82dd5ac40850fe7def91d26ffb6fe
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

src/platformheaders/nativecontexts/nativecontexts.pri

@@ -1,2 +1,3 @@
 HEADERS += $$PWD/qglxnativecontext.h \
-           $$PWD/qeglnativecontext.h
+           $$PWD/qeglnativecontext.h \
+           $$PWD/qcocoanativecontext.h

src/platformheaders/nativecontexts/qcocoanativecontext.h

@@ -0,0 +1,69 @@
+/****************************************************************************
+ **
+ ** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+ ** Contact: http://www.qt-project.org/legal
+ **
+ ** This file is part of the plugins of the Qt Toolkit.
+ **
+ ** $QT_BEGIN_LICENSE:LGPL$
+ ** Commercial License Usage
+ ** Licensees holding valid commercial Qt licenses may use this file in
+ ** accordance with the commercial license agreement provided with the
+ ** Software or, alternatively, in accordance with the terms contained in
+ ** a written agreement between you and Digia.  For licensing terms and
+ ** conditions see http://qt.digia.com/licensing.  For further information
+ ** use the contact form at http://qt.digia.com/contact-us.
+ **
+ ** GNU Lesser General Public License Usage
+ ** Alternatively, this file may be used under the terms of the GNU Lesser
+ ** General Public License version 2.1 as published by the Free Software
+ ** Foundation and appearing in the file LICENSE.LGPL included in the
+ ** packaging of this file.  Please review the following information to
+ ** ensure the GNU Lesser General Public License version 2.1 requirements
+ ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+ **
+ ** In addition, as a special exception, Digia gives you certain additional
+ ** rights.  These rights are described in the Digia Qt LGPL Exception
+ ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+ **
+ ** GNU General Public License Usage
+ ** Alternatively, this file may be used under the terms of the GNU
+ ** General Public License version 3.0 as published by the Free Software
+ ** Foundation and appearing in the file LICENSE.GPL included in the
+ ** packaging of this file.  Please review the following information to
+ ** ensure the GNU General Public License version 3.0 requirements will be
+ ** met: http://www.gnu.org/copyleft/gpl.html.
+ **
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+#ifndef QCOCOANATIVECONTEXT_H
+#define QCOCOANATIVECONTEXT_H
+
+#include <AppKit/NSOpenGL.h>
+
+QT_BEGIN_NAMESPACE
+
+struct QCocoaNativeContext
+{
+    QCocoaNativeContext()
+        : m_context(0)
+    { }
+
+    QCocoaNativeContext(NSOpenGLContext *ctx)
+        : m_context(ctx)
+    { }
+
+    NSOpenGLContext *context() const { return m_context; }
+
+private:
+    NSOpenGLContext *m_context;
+};
+
+QT_END_NAMESPACE
+
+Q_DECLARE_METATYPE(QCocoaNativeContext)
+
+#endif // QCOCOANATIVECONTEXT_H

src/plugins/platforms/cocoa/qcocoaglcontext.h

@@ -55,7 +55,7 @@ QT_BEGIN_NAMESPACE
 class QCocoaGLContext : public QPlatformOpenGLContext
 {
 public:
-    QCocoaGLContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share);
+    QCocoaGLContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, const QVariant &nativeHandle);
     ~QCocoaGLContext();
 
     QSurfaceFormat format() const;
@@ -77,6 +77,8 @@ public:
 
     void windowWasHidden();
 
+    QVariant nativeHandle() const;
+
 private:
     void setActiveWindow(QWindow *window);
     void updateSurfaceFormat();

src/plugins/platforms/cocoa/qcocoaglcontext.mm

@@ -46,6 +46,7 @@
 #include <qdebug.h>
 #include <QtCore/private/qcore_mac_p.h>
 #include <QtPlatformSupport/private/cglconvenience_p.h>
+#include <QtPlatformHeaders/qcocoanativecontext.h>
 
 #import <Cocoa/Cocoa.h>
 
@@ -117,11 +118,33 @@ static void updateFormatFromContext(QSurfaceFormat *format)
         format->setProfile(QSurfaceFormat::CompatibilityProfile);
 }
 
-QCocoaGLContext::QCocoaGLContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share)
+QCocoaGLContext::QCocoaGLContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share,
+                                 const QVariant &nativeHandle)
     : m_context(nil),
       m_shareContext(nil),
       m_format(format)
 {
+    if (!nativeHandle.isNull()) {
+        if (!nativeHandle.canConvert<QCocoaNativeContext>()) {
+            qWarning("QCocoaGLContext: Requires a QCocoaNativeContext");
+            return;
+        }
+        QCocoaNativeContext handle = nativeHandle.value<QCocoaNativeContext>();
+        NSOpenGLContext *context = handle.context();
+        if (!context) {
+            qWarning("QCocoaGLContext: No NSOpenGLContext given");
+            return;
+        }
+        m_context = context;
+        [m_context retain];
+        m_shareContext = share ? static_cast<QCocoaGLContext *>(share)->nsOpenGLContext() : nil;
+        // OpenGL surfaces can be ordered either above(default) or below the NSWindow.
+        const GLint order = qt_mac_resolveOption(1, "QT_MAC_OPENGL_SURFACE_ORDER");
+        [m_context setValues:&order forParameter:NSOpenGLCPSurfaceOrder];
+        updateSurfaceFormat();
+        return;
+    }
+
     // we only support OpenGL contexts under Cocoa
     if (m_format.renderableType() == QSurfaceFormat::DefaultRenderableType)
         m_format.setRenderableType(QSurfaceFormat::OpenGL);
@@ -168,6 +191,11 @@ QCocoaGLContext::~QCocoaGLContext()
     [m_context release];
 }
 
+QVariant QCocoaGLContext::nativeHandle() const
+{
+    return QVariant::fromValue<QCocoaNativeContext>(QCocoaNativeContext(m_context));
+}
+
 // Match up with createNSOpenGLPixelFormat!
 QSurfaceFormat QCocoaGLContext::format() const
 {

src/plugins/platforms/cocoa/qcocoaintegration.mm

@@ -422,7 +422,11 @@ QPlatformWindow *QCocoaIntegration::createPlatformWindow(QWindow *window) const
 
 QPlatformOpenGLContext *QCocoaIntegration::createPlatformOpenGLContext(QOpenGLContext *context) const
 {
-    return new QCocoaGLContext(context->format(), context->shareHandle());
+    QCocoaGLContext *glContext = new QCocoaGLContext(context->format(),
+                                                     context->shareHandle(),
+                                                     context->nativeHandle());
+    context->setNativeHandle(glContext->nativeHandle());
+    return glContext;
 }
 
 QPlatformBackingStore *QCocoaIntegration::createPlatformBackingStore(QWindow *window) const