QGLSceneNode::draw produced dim / blur result in large scale mesh

Hi,

The problem is encountered when using QGLAbstractScene to load large scale mesh.
The mesh could not be rendered property from QGLAbstractScene::mainNode directly. In stead, I need to break down to render each individual child node.
Otherwise shader effect (user or standard) could not be applied properly (see attachment bug.png vs dirty-fix.png).

#ifdef DIRTY_FIX

foreach(QGLSceneNode* node, m_scene->mainNode()->children())

node->draw(painter); // work

#else

m_scene->mainNode()->draw(painter); // doesn't work

#endif