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>

5 files changed, 44 insertions, 38 deletions

diff --git a/src/plugins/platforms/android/qandroidplatformintegration.cpp b/src/plugins/platforms/android/qandroidplatformintegration.cpp
index 372b32746d..8048bd6cff 100644
--- a/src/plugins/platforms/android/qandroidplatformintegration.cpp
+++ b/src/plugins/platforms/android/qandroidplatformintegration.cpp
@@ -44,6 +44,7 @@
 #include <QGuiApplication>
 #include <QOpenGLContext>
 #include <QOffscreenSurface>
+#include <QtGui/private/qoffscreensurface_p.h>
 #include <QThread>
 
 #include <QtGui/private/qeglpbuffer_p.h>
@@ -68,6 +69,8 @@
 #include "qandroidsystemlocale.h"
 #include "qandroidplatformoffscreensurface.h"
 
+#include <jni.h>
+
 #if QT_CONFIG(vulkan)
 #include "qandroidplatformvulkanwindow.h"
 #include "qandroidplatformvulkaninstance.h"
@@ -322,16 +325,20 @@ QPlatformOffscreenSurface *QAndroidPlatformIntegration::createPlatformOffscreenS
     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);
 }
 
+QOffscreenSurface *QAndroidPlatformIntegration::createOffscreenSurface(ANativeWindow *nativeSurface) const
+{
+    if (!QtAndroid::activity() || !nativeSurface)
+        return nullptr;
+
+    auto *surface = new QOffscreenSurface;
+    auto *surfacePrivate = QOffscreenSurfacePrivate::get(surface);
+    surfacePrivate->platformOffscreenSurface = new QAndroidPlatformOffscreenSurface(nativeSurface, m_eglDisplay, surface);
+    return surface;
+}
+
 QPlatformWindow *QAndroidPlatformIntegration::createPlatformWindow(QWindow *window) const
 {
     if (!QtAndroid::activity())
diff --git a/src/plugins/platforms/android/qandroidplatformintegration.h b/src/plugins/platforms/android/qandroidplatformintegration.h
index 30ab42ab34..012616839c 100644
--- a/src/plugins/platforms/android/qandroidplatformintegration.h
+++ b/src/plugins/platforms/android/qandroidplatformintegration.h
@@ -40,19 +40,17 @@
 #ifndef QANDROIDPLATFORMINTERATION_H
 #define QANDROIDPLATFORMINTERATION_H
 
-#include <QtGui/qtguiglobal.h>
+#include "qandroidinputcontext.h"
+#include "qandroidplatformscreen.h"
 
+#include <QtGui/qtguiglobal.h>
 #include <qpa/qplatformintegration.h>
 #include <qpa/qplatformmenu.h>
 #include <qpa/qplatformnativeinterface.h>
 #include <qpa/qplatformopenglcontext.h>
+#include <qpa/qplatformoffscreensurface.h>
 
 #include <EGL/egl.h>
-#include <jni.h>
-#include "qandroidinputcontext.h"
-
-#include "qandroidplatformscreen.h"
-
 #include <memory>
 
 QT_BEGIN_NAMESPACE
@@ -75,6 +73,7 @@ protected:
 
 class QAndroidPlatformIntegration : public QPlatformIntegration
                                   , QPlatformInterface::Private::QEGLIntegration
+                                  , QPlatformInterface::Private::QAndroidOffScreenIntegration
 {
     friend class QAndroidPlatformScreen;
 
@@ -94,6 +93,7 @@ public:
     QAbstractEventDispatcher *createEventDispatcher() const override;
     QAndroidPlatformScreen *screen() { return m_primaryScreen; }
     QPlatformOffscreenSurface *createPlatformOffscreenSurface(QOffscreenSurface *surface) const override;
+    QOffscreenSurface *createOffscreenSurface(ANativeWindow *nativeSurface) const override;
 
     void setAvailableGeometry(const QRect &availableGeometry);
     void setPhysicalSize(int width, int height);
diff --git a/src/plugins/platforms/android/qandroidplatformoffscreensurface.cpp b/src/plugins/platforms/android/qandroidplatformoffscreensurface.cpp
index f9589cea1a..9255ef4446 100644
--- a/src/plugins/platforms/android/qandroidplatformoffscreensurface.cpp
+++ b/src/plugins/platforms/android/qandroidplatformoffscreensurface.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 plugins of the Qt Toolkit.
@@ -39,28 +39,23 @@
 
 #include "qandroidplatformoffscreensurface.h"
 
-#include <QtGui/QOffscreenSurface>
 #include <QtGui/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)
+QAndroidPlatformOffscreenSurface::QAndroidPlatformOffscreenSurface(
+        ANativeWindow *nativeSurface, EGLDisplay display, QOffscreenSurface *offscreenSurface)
+    : QPlatformOffscreenSurface(offscreenSurface), m_display(display), m_surface(EGL_NO_SURFACE)
 {
-    // Get native handle
-    ANativeWindow *surfaceTexture = (ANativeWindow*)offscreenSurface->nativeHandle();
+    // FIXME: Read surface format properties from native surface using ANativeWindow_getFormat
+    m_format.setAlphaBufferSize(8);
+    m_format.setRedBufferSize(8);
+    m_format.setGreenBufferSize(8);
+    m_format.setBlueBufferSize(8);
 
-    EGLConfig config = q_configFromGLFormat(m_display, m_format, false);
-    if (config) {
-        const EGLint attributes[] = {
-            EGL_NONE
-        };
-        m_surface = eglCreateWindowSurface(m_display, config, surfaceTexture, attributes);
+    if (EGLConfig config = q_configFromGLFormat(m_display, m_format, false)) {
+        const EGLint attributes[] = { EGL_NONE };
+        m_surface = eglCreateWindowSurface(m_display, config, nativeSurface, attributes);
     }
 }
 
diff --git a/src/plugins/platforms/android/qandroidplatformoffscreensurface.h b/src/plugins/platforms/android/qandroidplatformoffscreensurface.h
index 033bc6a03f..3cfeab3bf2 100644
--- a/src/plugins/platforms/android/qandroidplatformoffscreensurface.h
+++ b/src/plugins/platforms/android/qandroidplatformoffscreensurface.h
@@ -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 plugins of the Qt Toolkit.
@@ -41,21 +41,26 @@
 #define QANDROIDPLATFORMOFFSCREENSURFACETEXTURE_H
 
 #include <qpa/qplatformoffscreensurface.h>
-#include <QtGui/private/qeglplatformcontext_p.h>
+#include <QtGui/qoffscreensurface_platform.h>
+
+#include <EGL/egl.h>
 
 QT_BEGIN_NAMESPACE
 class QOffscreenSurface;
-class QAndroidPlatformOffscreenSurface : public QPlatformOffscreenSurface
+class QAndroidPlatformOffscreenSurface : public QPlatformOffscreenSurface,
+                                         public QPlatformInterface::QAndroidPlatformOffscreenSurface
 {
 public:
-    QAndroidPlatformOffscreenSurface(EGLDisplay display, const QSurfaceFormat &format,
-                                            QOffscreenSurface *offscreenSurface);
+    QAndroidPlatformOffscreenSurface(ANativeWindow *nativeSurface, EGLDisplay display, 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; }
+
+    ANativeWindow *nativeSurface() const override { return (ANativeWindow *)surface(); };
+
 private:
     QSurfaceFormat m_format;
     EGLDisplay m_display;
diff --git a/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp b/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
index 330330a638..c51fbaf1d3 100644
--- a/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
+++ b/src/plugins/platforms/android/qandroidplatformopenglcontext.cpp
@@ -76,9 +76,8 @@ EGLSurface QAndroidPlatformOpenGLContext::eglSurfaceForPlatformSurface(QPlatform
     if (surface->surface()->surfaceClass() == QSurface::Window) {
         return static_cast<QAndroidPlatformOpenGLWindow *>(surface)->eglSurface(eglConfig());
     } else {
-        auto platformOffscreenSurface = static_cast<QPlatformOffscreenSurface*>(surface);
-        if (platformOffscreenSurface->offscreenSurface()->nativeHandle())
-            return static_cast<QAndroidPlatformOffscreenSurface *>(surface)->surface();
+        if (auto *platformOffscreenSurface = dynamic_cast<QAndroidPlatformOffscreenSurface *>(surface))
+            return platformOffscreenSurface->surface();
         else
             return static_cast<QEGLPbuffer *>(surface)->pbuffer();
     }