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>

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;
 }
 
 /*!
@@ -330,6 +334,26 @@ 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.
 
@@ -361,6 +385,19 @@ QPlatformOffscreenSurface *QOffscreenSurface::handle() const
     return d->platformOffscreenSurface;
 }
 
+/*!
+    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.
 

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);
 

src/plugins/platforms/android/android.pro

@@ -43,7 +43,8 @@ SOURCES += $$PWD/androidplatformplugin.cpp \
            $$PWD/qandroidplatformbackingstore.cpp \
            $$PWD/qandroidplatformopenglcontext.cpp \
            $$PWD/qandroidplatformforeignwindow.cpp \
-           $$PWD/qandroideventdispatcher.cpp
+           $$PWD/qandroideventdispatcher.cpp \
+           $$PWD/qandroidplatformoffscreensurface.cpp
 
 HEADERS += $$PWD/qandroidplatformintegration.h \
            $$PWD/androiddeadlockprotector.h \
@@ -71,7 +72,8 @@ HEADERS += $$PWD/qandroidplatformintegration.h \
            $$PWD/qandroidplatformbackingstore.h \
            $$PWD/qandroidplatformopenglcontext.h \
            $$PWD/qandroidplatformforeignwindow.h \
-           $$PWD/qandroideventdispatcher.h
+           $$PWD/qandroideventdispatcher.h \
+           $$PWD/qandroidplatformoffscreensurface.h
 
 qtConfig(android-style-assets): SOURCES += $$PWD/extract.cpp
 else: SOURCES += $$PWD/extract-dummy.cpp

src/plugins/platforms/android/qandroidplatformintegration.cpp

@@ -65,6 +65,7 @@
 #include "qandroidplatformservices.h"
 #include "qandroidplatformtheme.h"
 #include "qandroidsystemlocale.h"
+#include "qandroidplatformoffscreensurface.h"
 
 #include <QtPlatformHeaders/QEGLNativeContext>
 
@@ -262,12 +263,20 @@ QPlatformOffscreenSurface *QAndroidPlatformIntegration::createPlatformOffscreenS
 {
     if (!QtAndroid::activity())
         return nullptr;
+
     QSurfaceFormat format(surface->requestedFormat());
     format.setAlphaBufferSize(8);
     format.setRedBufferSize(8);
     format.setGreenBufferSize(8);
     format.setBlueBufferSize(8);
 
+    if (surface->nativeHandle()) {
+        // Adopt existing offscreen Surface
+        // The expectation is that nativeHandle is an ANativeWindow* representing
+        // an android.view.Surface
+        return new QAndroidPlatformOffscreenSurface(m_eglDisplay, format, surface);
+    }
+
     return new QEGLPbuffer(m_eglDisplay, format, surface);
 }
 

src/plugins/platforms/android/qandroidplatformoffscreensurface.cpp

@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qandroidplatformoffscreensurface.h"
+
+#include <QtGui/QOffscreenSurface>
+#include <QtEglSupport/private/qeglconvenience_p.h>
+
+#include <android/native_window.h>
+
+QT_BEGIN_NAMESPACE
+
+QAndroidPlatformOffscreenSurface::QAndroidPlatformOffscreenSurface(EGLDisplay display, const QSurfaceFormat &format, QOffscreenSurface *offscreenSurface)
+    : QPlatformOffscreenSurface(offscreenSurface)
+    , m_format(format)
+    , m_display(display)
+    , m_surface(EGL_NO_SURFACE)
+{
+    // Get native handle
+    ANativeWindow *surfaceTexture = (ANativeWindow*)offscreenSurface->nativeHandle();
+
+    EGLConfig config = q_configFromGLFormat(m_display, m_format, false);
+    if (config) {
+        const EGLint attributes[] = {
+            EGL_NONE
+        };
+        m_surface = eglCreateWindowSurface(m_display, config, surfaceTexture, attributes);
+    }
+}
+
+QAndroidPlatformOffscreenSurface::~QAndroidPlatformOffscreenSurface()
+{
+    eglDestroySurface(m_display, m_surface);
+}
+
+QT_END_NAMESPACE
+

src/plugins/platforms/android/qandroidplatformoffscreensurface.h

@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QANDROIDPLATFORMOFFSCREENSURFACETEXTURE_H
+#define QANDROIDPLATFORMOFFSCREENSURFACETEXTURE_H
+
+#include <qpa/qplatformoffscreensurface.h>
+#include <QtEglSupport/private/qeglplatformcontext_p.h>
+
+QT_BEGIN_NAMESPACE
+class QOffscreenSurface;
+class QAndroidPlatformOffscreenSurface : public QPlatformOffscreenSurface
+{
+public:
+    QAndroidPlatformOffscreenSurface(EGLDisplay display, const QSurfaceFormat &format,
+                                            QOffscreenSurface *offscreenSurface);
+    ~QAndroidPlatformOffscreenSurface();
+
+    QSurfaceFormat format() const override { return m_format; }
+    bool isValid() const override { return m_surface != EGL_NO_SURFACE; }
+
+    EGLSurface surface() const { return m_surface; }
+private:
+    QSurfaceFormat m_format;
+    EGLDisplay m_display;
+    EGLSurface m_surface;
+};
+
+QT_END_NAMESPACE
+
+#endif // QANDROIDPLATFORMOFFSCREENSURFACETEXTURE_H

src/plugins/platforms/android/qandroidplatformopenglcontext.cpp

@@ -41,11 +41,13 @@
 #include "qandroidplatformopenglcontext.h"
 #include "qandroidplatformopenglwindow.h"
 #include "qandroidplatformintegration.h"
+#include "qandroidplatformoffscreensurface.h"
 
 #include <QtEglSupport/private/qeglpbuffer_p.h>
 
 #include <QSurface>
 #include <QtGui/private/qopenglcontext_p.h>
+#include <QtGui/QOffscreenSurface>
 
 QT_BEGIN_NAMESPACE
 
@@ -110,10 +112,15 @@ bool QAndroidPlatformOpenGLContext::makeCurrent(QPlatformSurface *surface)
 
 EGLSurface QAndroidPlatformOpenGLContext::eglSurfaceForPlatformSurface(QPlatformSurface *surface)
 {
-    if (surface->surface()->surfaceClass() == QSurface::Window)
+    if (surface->surface()->surfaceClass() == QSurface::Window) {
         return static_cast<QAndroidPlatformOpenGLWindow *>(surface)->eglSurface(eglConfig());
-    else
-        return static_cast<QEGLPbuffer *>(surface)->pbuffer();
+    } else {
+        auto platformOffscreenSurface = static_cast<QPlatformOffscreenSurface*>(surface);
+        if (platformOffscreenSurface->offscreenSurface()->nativeHandle())
+            return static_cast<QAndroidPlatformOffscreenSurface *>(surface)->surface();
+        else
+            return static_cast<QEGLPbuffer *>(surface)->pbuffer();
+    }
 }
 
 QT_END_NAMESPACE