1 files changed, 27 insertions, 8 deletions

diff --git a/src/gui/painting/qrhibackingstore.cpp b/src/gui/painting/qrhibackingstore.cpp
index fd7045e3f6..d59cc2d83c 100644
--- a/src/gui/painting/qrhibackingstore.cpp
+++ b/src/gui/painting/qrhibackingstore.cpp
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #include "qrhibackingstore_p.h"
+#include <private/qimage_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -14,33 +15,51 @@ QRhiBackingStore::~QRhiBackingStore()
 {
 }
 
-void QRhiBackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)
+void QRhiBackingStore::flush(QWindow *flushedWindow, const QRegion &region, const QPoint &offset)
 {
     Q_UNUSED(region);
     Q_UNUSED(offset);
 
-    if (window != this->window())
-        return;
-
-    if (!rhi()) {
+    if (!rhi(flushedWindow)) {
         QPlatformBackingStoreRhiConfig rhiConfig;
-        switch (window->surfaceType()) {
+        switch (flushedWindow->surfaceType()) {
         case QSurface::OpenGLSurface:
             rhiConfig.setApi(QPlatformBackingStoreRhiConfig::OpenGL);
             break;
         case QSurface::MetalSurface:
             rhiConfig.setApi(QPlatformBackingStoreRhiConfig::Metal);
             break;
+        case QSurface::Direct3DSurface:
+            rhiConfig.setApi(QPlatformBackingStoreRhiConfig::D3D11);
+            break;
+        case QSurface::VulkanSurface:
+            rhiConfig.setApi(QPlatformBackingStoreRhiConfig::Vulkan);
+            break;
         default:
             Q_UNREACHABLE();
         }
+
         rhiConfig.setEnabled(true);
-        setRhiConfig(rhiConfig);
+        createRhi(flushedWindow, rhiConfig);
     }
 
     static QPlatformTextureList emptyTextureList;
     bool translucentBackground = m_image.hasAlphaChannel();
-    rhiFlush(window, window->devicePixelRatio(), region, offset, &emptyTextureList, translucentBackground);
+    rhiFlush(flushedWindow, flushedWindow->devicePixelRatio(),
+        region, offset, &emptyTextureList, translucentBackground);
+}
+
+QImage::Format QRhiBackingStore::format() const
+{
+    QImage::Format fmt = QRasterBackingStore::format();
+
+    // With render-to-texture widgets and QRhi-based flushing the backingstore
+    // image must have an alpha channel. Hence upgrading the format. Matches
+    // what other platforms (Windows, xcb) do.
+    if (QImage::toPixelFormat(fmt).alphaUsage() != QPixelFormat::UsesAlpha)
+        fmt = qt_maybeDataCompatibleAlphaVersion(fmt);
+
+    return fmt;
 }
 
 QT_END_NAMESPACE