shift renderer prototype to new node structure

app/node/output.cpp

@@ -23,8 +23,7 @@
 #include "node/node.h"
 
 NodeOutput::NodeOutput(const QString &id) :
-  NodeParam(id),
-  time_(-1)
+  NodeParam(id)
 {
 }
 
@@ -48,8 +47,12 @@ void NodeOutput::set_data_type(const NodeParam::DataType &type)
   }
 }
 
-const QVariant &NodeOutput::get_value(const rational& time)
+QVariant NodeOutput::get_value(const rational& time)
 {
+  QVariant v;
+
+  lock_.lock();
+
   if (time_ != time) {
     // Update the value
     value_ = parent()->Run(this, time);
@@ -57,6 +60,10 @@ const QVariant &NodeOutput::get_value(const rational& time)
     time_ = time;
   }
 
-  // The value should be have been set by this point
-  return value_;
+  v = value_;
+
+  lock_.unlock();
+
+  return v;
 }
+