Make sure OpenGL core profile context is used by GzScene3D

Should fix gazebosim/gz-rendering#128 .

Signed-off-by: Martin Pecka <peci1@seznam.cz>

src/gui/plugins/scene3d/Scene3D.cc

@@ -1922,8 +1922,18 @@ QSGNode *RenderWindowItem::updatePaintNode(QSGNode *_node,
     // and makeCurrent down below while setting up our own context.
     current->doneCurrent();
 
+    auto surfaceFormat = QSurfaceFormat();
+    surfaceFormat.setMajorVersion(3);
+    surfaceFormat.setMinorVersion(3);
+    surfaceFormat.setProfile(QSurfaceFormat::CoreProfile);
+
     this->dataPtr->renderThread->context = new QOpenGLContext();
-    this->dataPtr->renderThread->context->setFormat(current->format());
+    // Although it seems unbelievable, we can request another format for a
+    // shared context; it is needed because Qt selects by default a compat
+    // context which is much less likely to provide OpenGL 3.3 (only closed
+    // NVidia drivers). This means there will be mismatch between what is
+    // reported by QSG_INFO=1 and by OGRE.
+    this->dataPtr->renderThread->context->setFormat(surfaceFormat);
     this->dataPtr->renderThread->context->setShareContext(current);
     this->dataPtr->renderThread->context->create();
     this->dataPtr->renderThread->context->moveToThread(