Enable GL context sharing for QtQuick windows by default

This is required for running QWebEngine inside qmlscene. It can be disabled
with --disable-context-sharing and it remains off in QtQuick. Instead apps have
to use QWebEngine API to enable this, where this patch here is merely
convenience.

Change-Id: I123893a7c8c644c49c66fe2b42d2b7b2e03622d9
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

2 files changed, 16 insertions, 1 deletions

diff --git a/tools/qmlscene/main.cpp b/tools/qmlscene/main.cpp
index 531c894ada..f128e399b5 100644
--- a/tools/qmlscene/main.cpp
+++ b/tools/qmlscene/main.cpp
@@ -58,6 +58,7 @@
 #include <QtQuick/qquickview.h>
 
 #include <private/qabstractanimation_p.h>
+#include <private/qsgcontext_p.h>
 
 #ifdef QT_WIDGETS_LIB
 #include <QtWidgets/QApplication>
@@ -155,6 +156,7 @@ struct Options
         , quitImmediately(false)
         , resizeViewToRootItem(false)
         , multisample(false)
+        , contextSharing(true)
     {
     }
 
@@ -171,6 +173,7 @@ struct Options
     bool quitImmediately;
     bool resizeViewToRootItem;
     bool multisample;
+    bool contextSharing;
     QString translationFile;
 };
 
@@ -354,6 +357,7 @@ static void usage()
     qWarning("  --slow-animations ......................... Run all animations in slow motion");
     qWarning("  --resize-to-root .......................... Resize the window to the size of the root item");
     qWarning("  --quit .................................... Quit immediately after starting");
+    qWarning("  --disable-context-sharing ................. Disable the use of a shared GL context for QtQuick Windows");
     qWarning("  -I <path> ................................. Add <path> to the list of import paths");
     qWarning("  -B <name> <file> .......................... Add a named bundle");
     qWarning("  -translation <translationfile> ............ Set the language to run in");
@@ -393,6 +397,8 @@ int main(int argc, char ** argv)
                 options.resizeViewToRootItem = true;
             else if (lowerArgument == QLatin1String("--multisample"))
                 options.multisample = true;
+            else if (lowerArgument == QLatin1String("--disable-context-sharing"))
+                options.contextSharing = false;
             else if (lowerArgument == QLatin1String("-i") && i + 1 < argc)
                 imports.append(QString::fromLatin1(argv[++i]));
             else if (lowerArgument == QLatin1String("-b") && i + 2 < argc) {
@@ -448,6 +454,15 @@ int main(int argc, char ** argv)
         displayFileDialog(&options);
 #endif
 
+    // QWebEngine needs a shared context in order for the GPU thread to
+    // upload textures.
+    QScopedPointer<QOpenGLContext> shareContext;
+    if (options.contextSharing) {
+        shareContext.reset(new QOpenGLContext);
+        shareContext->create();
+        QSGContext::setSharedOpenGLContext(shareContext.data());
+    }
+
     int exitCode = 0;
 
     if (!options.file.isEmpty()) {
diff --git a/tools/qmlscene/qmlscene.pro b/tools/qmlscene/qmlscene.pro
index 07208ea703..0411fd8e31 100644
--- a/tools/qmlscene/qmlscene.pro
+++ b/tools/qmlscene/qmlscene.pro
@@ -1,4 +1,4 @@
-QT += qml quick core-private
+QT += qml quick quick-private gui-private core-private
 qtHaveModule(widgets): QT += widgets
 CONFIG += no_import_scan