Fix viewer scaling in macOS

Task-number: QT3DS-497
Change-Id: Id1ece6334a123960c796a4b7be238c680f2690e0
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

2 files changed, 16 insertions, 2 deletions

diff --git a/examples/studio3d/widgetviewer/main.cpp b/examples/studio3d/widgetviewer/main.cpp
index dd0b3a57..9ad8eed9 100644
--- a/examples/studio3d/widgetviewer/main.cpp
+++ b/examples/studio3d/widgetviewer/main.cpp
@@ -55,6 +55,22 @@
 
 int main(int argc, char *argv[])
 {
+    // to enable QOpenGLWidget to work on macOS, we must set the default
+    // QSurfaceFormat before QApplication is created. Otherwise context-sharing
+    // fails and QOpenGLWidget breaks.
+
+    // fortunately, we know which OpenGL version we can use on macOS, so we
+    // can simply hard-code it here.
+#if defined(Q_OS_MACOS)
+    QSurfaceFormat openGL33Format;
+    openGL33Format.setRenderableType(QSurfaceFormat::OpenGL);
+    openGL33Format.setProfile(QSurfaceFormat::CoreProfile);
+    openGL33Format.setMajorVersion(3);
+    openGL33Format.setMinorVersion(3);
+    openGL33Format.setStencilBufferSize(8);
+    QSurfaceFormat::setDefaultFormat(openGL33Format);
+#endif
+
     // Enable high DPI scaling
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 
diff --git a/src/Runtime/Source/Viewer/Qt3DSViewerApp.cpp b/src/Runtime/Source/Viewer/Qt3DSViewerApp.cpp
index 95658b3c..91bd1f28 100644
--- a/src/Runtime/Source/Viewer/Qt3DSViewerApp.cpp
+++ b/src/Runtime/Source/Viewer/Qt3DSViewerApp.cpp
@@ -520,13 +520,11 @@ void Q3DSViewerApp::Resize(int width, int height)
     QSize newSize(width, height);
     m_Impl.m_WindowSystem->SetWindowDimensions(newSize);
 
-#if !defined(Q_OS_MACOS)
     if (m_Impl.m_appInitSuccessful && m_Impl.m_tegraApp
             && m_Impl.m_tegraApp->GetTegraRenderEngine()) {
         QResizeEvent event = QResizeEvent(newSize, oldSize);
         m_Impl.m_tegraApp->HandleMessage(&event);
     }
-#endif
 }
 
 void Q3DSViewerApp::HandleKeyInput(Q3DStudio::EKeyCode inKeyCode, bool isPressed)