iOS: Tie QIOSContext FBOs to corresponding QPlatformWindow, not QWindow

A QWindow may be created() and destroyed() multiple times in the lifetime
of the window, each time resulting in a new platform window (QIOSWindow)
being created. This QIOSWindow is backed by a new UIView each time, hence
it needs a new FBO and renderbuffer-mapping, since the previous
renderbuffer was mapped to the old UIView.

This fixes a bug where a QWindow would not render after a destroy()
unless it was resized (which triggered new FBO/renderbuffers).

We need to inherit QObject so that we can watch the destroyed() signal.

Change-Id: I93172dd6280b86b49755bf7abddf061d7e6b66f1
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>

src/plugins/platforms/ios/qioscontext.h

@@ -48,6 +48,8 @@
 
 QT_BEGIN_NAMESPACE
 
+class QIOSWindow;
+
 class QIOSContext : public QObject, public QPlatformOpenGLContext
 {
     Q_OBJECT
@@ -87,7 +89,7 @@ private:
 
     static void deleteBuffers(const FramebufferObject &framebufferObject);
 
-    mutable QHash<QWindow *, FramebufferObject> m_framebufferObjects;
+    mutable QHash<QIOSWindow *, FramebufferObject> m_framebufferObjects;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/ios/qioscontext.mm

@@ -113,7 +113,7 @@ void QIOSContext::swapBuffers(QPlatformSurface *surface)
 {
     Q_ASSERT(surface && surface->surface()->surfaceType() == QSurface::OpenGLSurface);
     Q_ASSERT(surface->surface()->surfaceClass() == QSurface::Window);
-    QWindow *window = static_cast<QWindow *>(surface->surface());
+    QIOSWindow *window = static_cast<QIOSWindow *>(surface);
     Q_ASSERT(m_framebufferObjects.contains(window));
 
     [EAGLContext setCurrentContext:m_eaglContext];
@@ -124,7 +124,7 @@ void QIOSContext::swapBuffers(QPlatformSurface *surface)
 GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
 {
     Q_ASSERT(surface && surface->surface()->surfaceClass() == QSurface::Window);
-    QWindow *window = static_cast<QWindow *>(surface->surface());
+    QIOSWindow *window = static_cast<QIOSWindow *>(surface);
 
     FramebufferObject &framebufferObject = m_framebufferObjects[window];
 
@@ -155,8 +155,7 @@ GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
     }
 
     // Ensure that the FBO's buffers match the size of the layer
-    QIOSWindow *platformWindow = static_cast<QIOSWindow *>(surface);
+    UIView *view = reinterpret_cast<UIView *>(window->winId());
-    UIView *view = reinterpret_cast<UIView *>(platformWindow->winId());
     CAEAGLLayer *layer = static_cast<CAEAGLLayer *>(view.layer);
     if (framebufferObject.renderbufferWidth != (layer.frame.size.width * layer.contentsScale) ||
         framebufferObject.renderbufferHeight != (layer.frame.size.height * layer.contentsScale)) {
@@ -191,7 +190,7 @@ GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
 
 void QIOSContext::windowDestroyed(QObject *object)
 {
-    QWindow *window = static_cast<QWindow *>(object);
+    QIOSWindow *window = static_cast<QIOSWindow *>(object);
     if (m_framebufferObjects.contains(window)) {
         EAGLContext *originalContext = [EAGLContext currentContext];
         [EAGLContext setCurrentContext:m_eaglContext];

src/plugins/platforms/ios/qioswindow.h

@@ -58,8 +58,10 @@ QT_BEGIN_NAMESPACE
 
 @class QUIView;
 
-class QIOSWindow : public QPlatformWindow
+class QIOSWindow : public QObject, public QPlatformWindow
 {
+    Q_OBJECT
+
 public:
     explicit QIOSWindow(QWindow *window);
     ~QIOSWindow();

src/plugins/platforms/ios/qioswindow.mm

@@ -342,7 +342,7 @@ QIOSWindow::QIOSWindow(QWindow *window)
     , m_normalGeometry(QPlatformWindow::geometry())
     , m_windowLevel(0)
 {
-    setParent(parent());
+    setParent(QPlatformWindow::parent());
     setWindowState(window->windowState());
 }
 
@@ -527,4 +527,6 @@ qreal QIOSWindow::devicePixelRatio() const
     return m_view.contentScaleFactor;
 }
 
+#include "moc_qioswindow.cpp"
+
 QT_END_NAMESPACE