message: don't insert node duplicates when gathering nodes during visitation
diff: @@ -47,8 +47,19 @@ namespace ospray {
  inline bool GatherNodesByName::visit(Node &node)
  {
  - if (node.name() == this->name)
  + if (node.name() == this->name) {
  + auto itr = std::find_if(
  + nodes.begin(),
  + nodes.end(),
  + [&](const std::shared_ptr<Node> &nodeInList) {
  + return nodeInList.get() == &node;
  + }
  + );
  +
  + if (itr == nodes.end())
  nodes.push_back(node.shared_from_this());
  + }
  +
  return true;
  }
  