Support RasterGLSurface windows

In an attempt to make QOpenGLWidget and QQuickWidget working on Wayland.

Since Qt 5.3 all widget windows are of type RasterGLSurface (given that
the plugin reports this capability which wayland will, with this patch).
Such a window can behave either like a raster or an OpenGL window.

This concept maps badly to platform plugins that have a rigid separation
between raster and OpenGL platform window implementations. From now on,
the OpenGL window implementation, that is used pretty much always,
except for raw RasterSurface windows, must be prepared to behave like
a raster window too, which involves having a backingstore.

Change-Id: I0226704b8d5893843fcae68059c5fe9ad2f5e761
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

src/plugins/platforms/wayland/hardwareintegration/qwaylandclientbufferintegration_p.h

@@ -62,6 +62,8 @@ public:
 
     virtual void initialize(QWaylandDisplay *display) = 0;
 
+    virtual bool isValid() const { return true; }
+
     virtual bool supportsThreadedOpenGL() const { return false; }
 
     virtual QWaylandWindow *createEglWindow(QWindow *window) = 0;

src/plugins/platforms/wayland/qwaylandintegration.cpp

@@ -42,9 +42,9 @@
 #include "qwaylandintegration_p.h"
 
 #include "qwaylanddisplay_p.h"
+#include "qwaylandshmwindow_p.h"
 #include "qwaylandinputcontext_p.h"
 #include "qwaylandshmbackingstore_p.h"
-#include "qwaylandshmwindow_p.h"
 #include "qwaylandnativeinterface_p.h"
 #include "qwaylandclipboard_p.h"
 #include "qwaylanddnd_p.h"
@@ -162,14 +162,18 @@ bool QWaylandIntegration::hasCapability(QPlatformIntegration::Capability cap) co
     case MultipleWindows:
     case NonFullScreenWindows:
         return true;
+    case RasterGLSurface:
+        return true;
     default: return QPlatformIntegration::hasCapability(cap);
     }
 }
 
 QPlatformWindow *QWaylandIntegration::createPlatformWindow(QWindow *window) const
 {
-    if (window->surfaceType() == QWindow::OpenGLSurface && mDisplay->clientBufferIntegration())
+    if ((window->surfaceType() == QWindow::OpenGLSurface || window->surfaceType() == QWindow::RasterGLSurface)
+        && mDisplay->clientBufferIntegration())
         return mDisplay->clientBufferIntegration()->createEglWindow(window);
+
     return new QWaylandShmWindow(window);
 }
 
@@ -255,7 +259,7 @@ QWaylandClientBufferIntegration *QWaylandIntegration::clientBufferIntegration()
     if (!mClientBufferIntegrationInitialized)
         const_cast<QWaylandIntegration *>(this)->initializeClientBufferIntegration();
 
-    return mClientBufferIntegration;
+    return mClientBufferIntegration && mClientBufferIntegration->isValid() ? mClientBufferIntegration : 0;
 }
 
 QWaylandServerBufferIntegration *QWaylandIntegration::serverBufferIntegration() const

src/plugins/platforms/wayland/qwaylandshmbackingstore.cpp

@@ -39,14 +39,12 @@
 **
 ****************************************************************************/
 #include "qwaylandshmbackingstore_p.h"
-
-#include <QtCore/qdebug.h>
-
+#include "qwaylandwindow_p.h"
 #include "qwaylanddisplay_p.h"
-#include "qwaylandshmwindow_p.h"
 #include "qwaylandscreen_p.h"
 #include "qwaylanddecoration_p.h"
 
+#include <QtCore/qdebug.h>
 #include <QtGui/QPainter>
 
 #include <wayland-client.h>
@@ -156,9 +154,7 @@ QWaylandShmBackingStore::~QWaylandShmBackingStore()
 
 QPaintDevice *QWaylandShmBackingStore::paintDevice()
 {
-    if (!windowDecoration())
-        return mBackBuffer->image();
-    return mBackBuffer->imageInsideMargins(windowDecorationMargins());
+    return contentSurface();
 }
 
 void QWaylandShmBackingStore::beginPaint(const QRegion &)
@@ -166,13 +162,11 @@ void QWaylandShmBackingStore::beginPaint(const QRegion &)
     mPainting = true;
     ensureSize();
 
-    if (waylandWindow()->attached() && mBackBuffer == waylandWindow()->attached() && mFrameCallback) {
-        QWaylandShmWindow *waylandWindow = static_cast<QWaylandShmWindow *>(window()->handle());
-        Q_ASSERT(waylandWindow->windowType() == QWaylandWindow::Shm);
-        waylandWindow->waitForFrameSync();
-    }
+    QWaylandWindow *window = waylandWindow();
+    if (window->attached() && mBackBuffer == window->attached() && mFrameCallback)
+        window->waitForFrameSync();
 
-    waylandWindow()->setCanResize(false);
+    window->setCanResize(false);
 }
 
 void QWaylandShmBackingStore::endPaint()
@@ -190,9 +184,15 @@ void QWaylandShmBackingStore::ensureSize()
 
 void QWaylandShmBackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)
 {
+    // Invoked when the window is of type RasterSurface or when the window is
+    // RasterGLSurface and there are no child widgets requiring OpenGL composition.
+
+    // For the case of RasterGLSurface + having to compose, the composeAndFlush() is
+    // called instead. The default implementation from QPlatformBackingStore is sufficient
+    // however so no need to reimplement that.
+
     Q_UNUSED(window);
     Q_UNUSED(offset);
-    Q_ASSERT(waylandWindow()->windowType() == QWaylandWindow::Shm);
 
     if (windowDecoration() && windowDecoration()->isDirty())
         updateDecorations();
@@ -260,6 +260,11 @@ QImage *QWaylandShmBackingStore::entireSurface() const
     return mBackBuffer->image();
 }
 
+QImage *QWaylandShmBackingStore::contentSurface() const
+{
+    return windowDecoration() ? mBackBuffer->imageInsideMargins(windowDecorationMargins()) : mBackBuffer->image();
+}
+
 void QWaylandShmBackingStore::updateDecorations()
 {
     QPainter decorationPainter(entireSurface());
@@ -302,11 +307,19 @@ QMargins QWaylandShmBackingStore::windowDecorationMargins() const
     return QMargins();
 }
 
-QWaylandShmWindow *QWaylandShmBackingStore::waylandWindow() const
+QWaylandWindow *QWaylandShmBackingStore::waylandWindow() const
 {
-    return static_cast<QWaylandShmWindow *>(window()->handle());
+    return static_cast<QWaylandWindow *>(window()->handle());
 }
 
+QImage QWaylandShmBackingStore::toImage() const
+{
+    // Invoked from QPlatformBackingStore::composeAndFlush() that is called
+    // instead of flush() for widgets that have renderToTexture children
+    // (QOpenGLWidget, QQuickWidget).
+
+    return *contentSurface();
+}
 
 void QWaylandShmBackingStore::done(void *data, wl_callback *callback, uint32_t time)
 {
@@ -315,7 +328,7 @@ void QWaylandShmBackingStore::done(void *data, wl_callback *callback, uint32_t t
             static_cast<QWaylandShmBackingStore *>(data);
     if (callback != self->mFrameCallback) // others, like QWaylandWindow, may trigger callbacks too
         return;
-    QWaylandShmWindow *window = self->waylandWindow();
+    QWaylandWindow *window = self->waylandWindow();
     wl_callback_destroy(self->mFrameCallback);
     self->mFrameCallback = 0;
 

src/plugins/platforms/wayland/qwaylandshmbackingstore_p.h

@@ -52,7 +52,7 @@ QT_BEGIN_NAMESPACE
 
 class QWaylandDisplay;
 class QWaylandDecoration;
-class QWaylandShmWindow;
+class QWaylandWindow;
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandShmBuffer : public QWaylandBuffer {
 public:
@@ -87,11 +87,14 @@ public:
 
     QMargins windowDecorationMargins() const;
     QImage *entireSurface() const;
+    QImage *contentSurface() const;
     void ensureSize();
 
-    QWaylandShmWindow *waylandWindow() const;
+    QWaylandWindow *waylandWindow() const;
     void iterateBuffer();
 
+    QImage toImage() const Q_DECL_OVERRIDE;
+
 private:
     void updateDecorations();
 

src/plugins/platforms/wayland/qwaylandshmwindow.cpp

@@ -51,13 +51,11 @@ QT_BEGIN_NAMESPACE
 
 QWaylandShmWindow::QWaylandShmWindow(QWindow *window)
     : QWaylandWindow(window)
-    , mBackingStore(0)
 {
 }
 
 QWaylandShmWindow::~QWaylandShmWindow()
 {
-
 }
 
 QWaylandWindow::WindowType QWaylandShmWindow::windowType() const
@@ -65,9 +63,4 @@ QWaylandWindow::WindowType QWaylandShmWindow::windowType() const
     return QWaylandWindow::Shm;
 }
 
-void QWaylandShmWindow::setBackingStore(QWaylandShmBackingStore *backingStore)
-{
-    mBackingStore = backingStore;
-}
-
 QT_END_NAMESPACE

src/plugins/platforms/wayland/qwaylandshmwindow_p.h

@@ -47,8 +47,6 @@
 
 QT_BEGIN_NAMESPACE
 
-class QWaylandShmBackingStore;
-
 class Q_WAYLAND_CLIENT_EXPORT QWaylandShmWindow : public QWaylandWindow
 {
 public:
@@ -57,19 +55,8 @@ public:
 
     WindowType windowType() const;
     QSurfaceFormat format() const { return QSurfaceFormat(); }
-
-    void setBackingStore(QWaylandShmBackingStore *backingStore);
-    QWaylandShmBackingStore *backingStore() const;
-
-private:
-    QWaylandShmBackingStore *mBackingStore;
 };
 
-inline QWaylandShmBackingStore *QWaylandShmWindow::backingStore() const
-{
-    return mBackingStore;
-}
-
 QT_END_NAMESPACE
 
 #endif // QWAYLANDSHMWINDOW_H

src/plugins/platforms/wayland/qwaylandwindow_p.h

@@ -63,6 +63,7 @@ class QWaylandSubSurface;
 class QWaylandDecoration;
 class QWaylandInputDevice;
 class QWaylandScreen;
+class QWaylandShmBackingStore;
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandWindowConfigure
 {
@@ -179,6 +180,9 @@ public:
     QVariant property(const QString &name);
     QVariant property(const QString &name, const QVariant &defaultValue);
 
+    void setBackingStore(QWaylandShmBackingStore *backingStore) { mBackingStore = backingStore; }
+    QWaylandShmBackingStore *backingStore() const { return mBackingStore; }
+
 public slots:
     void requestResize();
 
@@ -216,6 +220,8 @@ protected:
 
     Qt::WindowState mState;
 
+    QWaylandShmBackingStore *mBackingStore;
+
 private:
     bool setWindowStateInternal(Qt::WindowState flags);
     void setGeometry_helper(const QRect &rect);