Added osg::Node::getValidStateSet().

include/osg/Node

@@ -177,10 +177,15 @@ class SG_EXPORT Node : public Object
         /** set the node's StateSet.*/
         inline void setStateSet(osg::StateSet* dstate) { _dstate = dstate; }
 
-        /** return the node's StateSet.*/
+        /** return the node's StateSet, if one does not already exist create it
+          * set the node and return the newly created StateSet. This ensures
+          * that a valid StateSet is always returned and can be used directly.*/
+        osg::StateSet* getValidStateSet();
+
+        /** return the node's StateSet. returns NULL if a stateset is not attached.*/
         inline osg::StateSet* getStateSet() { return _dstate.get(); }
 
-        /** return the node's const StateSet.*/
+        /** return the node's const StateSet. returns NULL if a stateset is not attached.*/
         inline const osg::StateSet* getStateSet() const { return _dstate.get(); }
 
         /** get the bounding sphere of node.

src/osg/Node.cpp

@@ -68,6 +68,13 @@ void Node::ascend(NodeVisitor& nv)
     std::for_each(_parents.begin(),_parents.end(),NodeAcceptOp(nv));
 }
 
+osg::StateSet* Node::getValidStateSet()
+{
+    if (!_dstate) _dstate = osgNew StateSet;
+    return _dstate.get();
+}
+
+
 void Node::setAppCallback(NodeCallback* nc)
 {
     // if no changes just return.