Add QOffScreenSurface platform API abstraction

This follows the work done in 6ff79478a44fce12ca18832a56db4a370a9ff417.

The API is available by including qoffscreensurface.h, scoped in
the QPlatformInterface namespace. The namespace
exposes platform specific type-safe interfaces that provide:

 a) Factory functions for adopting native contexts, e.g.

    QAndroidPlatformOffscreenSurface::fromNative(ANativeWindow);

 b) Access to underlying native handles, e.g.

    surface->platformInterface<QAndroidPlatformOffscreenSurface>()
                ->nativeSurface()

Fixes: QTBUG-85874
Change-Id: I29c459866e0355a52320d5d473e8b147e050acb3
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 14 insertions, 67 deletions

diff --git a/src/gui/kernel/qoffscreensurface.cpp b/src/gui/kernel/qoffscreensurface.cpp
index fbd5c6a079..9875911d30 100644
--- a/src/gui/kernel/qoffscreensurface.cpp
+++ b/src/gui/kernel/qoffscreensurface.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -42,7 +42,7 @@
 #include "qguiapplication_p.h"
 #include "qscreen.h"
 #include "qplatformintegration.h"
-#include "qplatformoffscreensurface.h"
+#include "qoffscreensurface_p.h"
 #include "qwindow.h"
 #include "qplatformwindow.h"
 
@@ -50,6 +50,18 @@
 
 QT_BEGIN_NAMESPACE
 
+
+/*!
+    \fn T QOffScreenSurface::platformInterface<T>()
+
+    Returns a platform interface of type T for the surface.
+
+    This function provides access to platform specific functionality
+    of QOffScreenSurface, as defined in the QPlatformInterface namespace.
+
+    If the requested interface is not available a \nullptr is returned.
+*/
+
 /*!
     \class QOffscreenSurface
     \inmodule QtGui
@@ -91,36 +103,6 @@ QT_BEGIN_NAMESPACE
     native surface. For the use cases of QOffscreenSurface (rendering to FBOs, texture
     upload) this is not a problem.
 */
-class Q_GUI_EXPORT QOffscreenSurfacePrivate : public QObjectPrivate
-{
-    Q_DECLARE_PUBLIC(QOffscreenSurface)
-
-public:
-    QOffscreenSurfacePrivate()
-        : QObjectPrivate()
-        , surfaceType(QSurface::OpenGLSurface)
-        , platformOffscreenSurface(nullptr)
-        , offscreenWindow(nullptr)
-        , requestedFormat(QSurfaceFormat::defaultFormat())
-        , screen(nullptr)
-        , size(1, 1)
-        , nativeHandle(nullptr)
-    {
-    }
-
-    ~QOffscreenSurfacePrivate()
-    {
-    }
-
-    QSurface::SurfaceType surfaceType;
-    QPlatformOffscreenSurface *platformOffscreenSurface;
-    QWindow *offscreenWindow;
-    QSurfaceFormat requestedFormat;
-    QScreen *screen;
-    QSize size;
-    void *nativeHandle;
-};
-
 
 /*!
     \since 5.10
@@ -228,8 +210,6 @@ void QOffscreenSurface::destroy()
         delete d->offscreenWindow;
         d->offscreenWindow = nullptr;
     }
-
-    d->nativeHandle = nullptr;
 }
 
 /*!
@@ -344,26 +324,6 @@ void QOffscreenSurface::setScreen(QScreen *newScreen)
 }
 
 /*!
-    Sets the native handle to which the offscreen surface is connected to \a handle.
-
-    The native handle will be resolved in the create() function. Calling
-    this function after create() will not re-create a native surface.
-
-    \note The interpretation of the native handle is platform specific.  Only
-    some platforms will support adopting native handles of offscreen surfaces
-    and platforms that do not implement this support will ignore the handle.
-
-    \since 5.9
-    \sa nativeHandle()
-*/
-
-void QOffscreenSurface::setNativeHandle(void *handle)
-{
-    Q_D(QOffscreenSurface);
-    d->nativeHandle = handle;
-}
-
-/*!
     Called when the offscreen surface's screen is destroyed.
 
     \internal
@@ -395,19 +355,6 @@ QPlatformOffscreenSurface *QOffscreenSurface::handle() const
 }
 
 /*!
-    Returns an optional native handle to which the offscreen surface is connected.
-
-    \since 5.9
-    \sa setNativeHandle()
-*/
-
-void *QOffscreenSurface::nativeHandle() const
-{
-    Q_D(const QOffscreenSurface);
-    return d->nativeHandle;
-}
-
-/*!
     Returns the platform surface corresponding to the offscreen surface.
 
     \internal