Merge remote-tracking branch 'origin/5.6.0' into 5.6

Change-Id: I0b190005377a23a91da3563428e223b8a3b18333

2 files changed, 32 insertions, 10 deletions

diff --git a/src/platformsupport/platformcompositor/qopenglcompositor.cpp b/src/platformsupport/platformcompositor/qopenglcompositor.cpp
index 2e386532e2..c65d69e842 100644
--- a/src/platformsupport/platformcompositor/qopenglcompositor.cpp
+++ b/src/platformsupport/platformcompositor/qopenglcompositor.cpp
@@ -57,7 +57,7 @@ QT_BEGIN_NAMESPACE
 
     It is up to the platform plugin to manage the lifetime of the
     compositor (instance(), destroy()), set the correct destination
-    context and window as early as possible (setTargetWindow()),
+    context and window as early as possible (setTarget()),
     register the composited windows as they are shown, activated,
     raised and lowered (addWindow(), moveToTop(), etc.), and to
     schedule repaints (update()).
@@ -177,11 +177,11 @@ static inline QRect toBottomLeftRect(const QRect &topLeftRect, int windowHeight)
 
 static void clippedBlit(const QPlatformTextureList *textures, int idx, const QRect &targetWindowRect, QOpenGLTextureBlitter *blitter)
 {
-    const QRect rectInWindow = textures->geometry(idx);
-    QRect clipRect = textures->clipRect(idx);
+    const QRect clipRect = textures->clipRect(idx);
     if (clipRect.isEmpty())
-        clipRect = QRect(QPoint(0, 0), rectInWindow.size());
+        return;
 
+    const QRect rectInWindow = textures->geometry(idx);
     const QRect clippedRectInWindow = rectInWindow & clipRect.translated(rectInWindow.topLeft());
     const QRect srcRect = toBottomLeftRect(clipRect, rectInWindow.height());
 
diff --git a/src/platformsupport/platformcompositor/qopenglcompositorbackingstore.cpp b/src/platformsupport/platformcompositor/qopenglcompositorbackingstore.cpp
index fee3146f04..8ec5d20e05 100644
--- a/src/platformsupport/platformcompositor/qopenglcompositorbackingstore.cpp
+++ b/src/platformsupport/platformcompositor/qopenglcompositorbackingstore.cpp
@@ -34,6 +34,7 @@
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QWindow>
 #include <QtGui/QPainter>
+#include <QtGui/QOffscreenSurface>
 #include <qpa/qplatformbackingstore.h>
 #include <private/qwindow_p.h>
 
@@ -82,13 +83,28 @@ QOpenGLCompositorBackingStore::~QOpenGLCompositorBackingStore()
 {
     if (m_bsTexture) {
         QOpenGLContext *ctx = QOpenGLContext::currentContext();
+        // With render-to-texture-widgets QWidget makes sure the TLW's shareContext() is
+        // made current before destroying backingstores. That is however not the case for
+        // windows with regular widgets only.
+        QScopedPointer<QOffscreenSurface> tempSurface;
+        if (!ctx) {
+            ctx = QOpenGLCompositor::instance()->context();
+            tempSurface.reset(new QOffscreenSurface);
+            tempSurface->setFormat(ctx->format());
+            tempSurface->create();
+            ctx->makeCurrent(tempSurface.data());
+        }
+
         if (ctx && m_bsTextureContext && ctx->shareGroup() == m_bsTextureContext->shareGroup())
             glDeleteTextures(1, &m_bsTexture);
         else
             qWarning("QOpenGLCompositorBackingStore: Texture is not valid in the current context");
+
+        if (tempSurface)
+            ctx->doneCurrent();
     }
 
-    delete m_textures;
+    delete m_textures; // this does not actually own any GL resources
 }
 
 QPaintDevice *QOpenGLCompositorBackingStore::paintDevice()
@@ -158,16 +174,15 @@ void QOpenGLCompositorBackingStore::updateTexture()
 
 void QOpenGLCompositorBackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)
 {
-    // Called for ordinary raster windows. This is rare since RasterGLSurface
-    // support is claimed which leads to having all QWidget windows marked as
-    // RasterGLSurface instead of just Raster. These go through
-    // compositeAndFlush() instead of this function.
+    // Called for ordinary raster windows.
 
     Q_UNUSED(region);
     Q_UNUSED(offset);
 
     QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
     QOpenGLContext *dstCtx = compositor->context();
+    Q_ASSERT(dstCtx);
+
     QWindow *dstWin = compositor->targetWindow();
     if (!dstWin)
         return;
@@ -184,7 +199,7 @@ void QOpenGLCompositorBackingStore::composeAndFlush(QWindow *window, const QRegi
                                                QPlatformTextureList *textures, QOpenGLContext *context,
                                                bool translucentBackground)
 {
-    // QOpenGLWidget/QQuickWidget content provided as textures. The raster content should go on top.
+    // QOpenGLWidget/QQuickWidget content provided as textures. The raster content goes on top.
 
     Q_UNUSED(region);
     Q_UNUSED(offset);
@@ -193,6 +208,12 @@ void QOpenGLCompositorBackingStore::composeAndFlush(QWindow *window, const QRegi
 
     QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
     QOpenGLContext *dstCtx = compositor->context();
+    Q_ASSERT(dstCtx); // setTarget() must have been called before, e.g. from QEGLFSWindow
+
+    // The compositor's context and the context to which QOpenGLWidget/QQuickWidget
+    // textures belong are not the same. They share resources, though.
+    Q_ASSERT(context->shareGroup() == dstCtx->shareGroup());
+
     QWindow *dstWin = compositor->targetWindow();
     if (!dstWin)
         return;
@@ -254,6 +275,7 @@ void QOpenGLCompositorBackingStore::resize(const QSize &size, const QRegion &sta
     if (m_bsTexture) {
         glDeleteTextures(1, &m_bsTexture);
         m_bsTexture = 0;
+        m_bsTextureContext = Q_NULLPTR;
     }
 }