Android: Enable Adoption of ANativeWindow handle as a QOffscreenSurface

This is done by adding an API to QOffscreenSurface to enable setting a
native handle which can represent a native offscreen surface.  When
using the TexureView it is necessary to render to SurfaceTexture objects
which are exposed as offscreen window surfaces.  After wraping a
SurfaceTexture in a android.view.Surface object and passing it to C++
via the JNI, it is possible to get the needed ANativeWindow* handle
required to pass to eglCreateWindowSurface. So by setting this native
handle Qt can then render to this "native" offscreen surface.

Change-Id: If7fc5ac7ac588fe6c3a6fb883ea7e439d095470f
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/src/gui/kernel/qoffscreensurface.cpp b/src/gui/kernel/qoffscreensurface.cpp
index a9535a6ad7..e8a86590b5 100644
--- a/src/gui/kernel/qoffscreensurface.cpp
+++ b/src/gui/kernel/qoffscreensurface.cpp
@@ -102,6 +102,7 @@ public:
         , requestedFormat(QSurfaceFormat::defaultFormat())
         , screen(0)
         , size(1, 1)
+        , nativeHandle(nullptr)
     {
     }
 
@@ -115,6 +116,7 @@ public:
     QSurfaceFormat requestedFormat;
     QScreen *screen;
     QSize size;
+    void *nativeHandle;
 };
 
 
@@ -217,6 +219,8 @@ void QOffscreenSurface::destroy()
         delete d->offscreenWindow;
         d->offscreenWindow = 0;
     }
+
+    d->nativeHandle = nullptr;
 }
 
 /*!
@@ -331,6 +335,26 @@ void QOffscreenSurface::setScreen(QScreen *newScreen)
 }
 
 /*!
+    Sets the native handle to which the offscreen surface is connected.
+
+    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
@@ -362,6 +386,19 @@ 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
diff --git a/src/gui/kernel/qoffscreensurface.h b/src/gui/kernel/qoffscreensurface.h
index bacc9c851a..35c498c89a 100644
--- a/src/gui/kernel/qoffscreensurface.h
+++ b/src/gui/kernel/qoffscreensurface.h
@@ -79,6 +79,9 @@ public:
 
     QPlatformOffscreenSurface *handle() const;
 
+    void *nativeHandle() const;
+    void setNativeHandle(void *handle);
+
 Q_SIGNALS:
     void screenChanged(QScreen *screen);