Added ParentList's into StateSet, Uniform and StateAttribute in preparation for

providing update and event handling.

src/osg/Node.cpp

@@ -86,6 +86,21 @@ void Node::ascend(NodeVisitor& nv)
     std::for_each(_parents.begin(),_parents.end(),NodeAcceptOp(nv));
 }
 
+void Node::setStateSet(osg::StateSet* stateset)
+{
+    // do nothing if nothing changed.
+    if (_stateset==stateset) return;
+    
+    // remove this node from the current statesets parent list 
+    if (_stateset.valid()) _stateset->removeParent(this);
+    
+    // set the stateset.
+    _stateset = stateset;
+    
+    // add this node to the new stateset to the parent list.
+    if (_stateset.valid()) _stateset->addParent(this);
+}
+
 osg::StateSet* Node::getOrCreateStateSet()
 {
     if (!_stateset) _stateset = new StateSet;