o Added osgUtil::StateOptimizeVisitor which traversing the scene

graph and builds up a map of all StateAttributes and StateSets
    and then removes the duplicates. This promotes state sharing
    throughout the scene graph which inturn can significantly improve
    performance thanks to reduced state changing. Particularily
    effective on datasets where a great deal of duplicated state
exists.
  o Added pure virtual compare(const osg::StateAttribute&)
    method to osg::StateAttribute, and implemented it in all the
    subclasses from StateAttribute. Added <,== & != operator
    on StateAttribute and Matrix to support new StateOptimizeVisitor.
  o Added META_Object, META_Node and META_StateAttribute macros to
    Object, Node and StateAttribute respectively which define the
    standard pure virtual methods such as clone, className
    & isSameKindAs.  Changed all the appropriate header files to
    use these macro's rather define them in each header, these cleans
    up the headers considerably.
  o Corrected the implementation of osg::Light::getType so it correctly
    uses a unique type for each of the OpenGL lights (GL_LIGHT0..
    GL_LIGHT7 relates to osg::StateAttriburte::LIGHT_0..LIGHT_7.
  o Changed the definition of osg::StateStateAttribute::Type to
    is now a unsigned int rather than an enum, and have changed the
    name of the previous Type enum list to be Types.  This makes it
    more consistent with the difination of values found in
StateAttribute
    and also easier to extend with having to cast to an enum.
  o From Pail Fredrikson, updated Maitrx.new implemention which uses
    the same matrix orientation as the original Matrix implemention.

src/osgUtil/OptimizeStateVisitor.cpp

@@ -0,0 +1,132 @@
+#include <osg/Notify>
+#include <osg/Geode>
+
+#include <osgUtil/OptimizeStateVisitor>
+
+#include <typeinfo>
+#include <algorithm>
+
+using namespace osgUtil;
+
+
+struct LessAttributeFunctor
+{
+    bool operator () (const osg::StateAttribute* lhs,const osg::StateAttribute* rhs) const
+    {
+        return (*lhs<*rhs); 
+    }
+};
+/*
+struct LessStateSetFunctor
+{
+    bool operator () (const osg::StateSet* lhs,const osg::StateSet* rhs) const
+    {
+        return (*lhs<*rhs); 
+    }
+};
+*/
+void OptimizeStateVisitor::reset()
+{
+    _statesets.clear();
+}
+
+void OptimizeStateVisitor::addStateSet(osg::StateSet* stateset)
+{
+    _statesets.insert(stateset);
+}
+
+void OptimizeStateVisitor::apply(osg::Node& node)
+{
+    osg::StateSet* ss = node.getStateSet();
+    if (ss) addStateSet(ss);
+
+    traverse(node);
+}
+
+void OptimizeStateVisitor::apply(osg::Geode& geode)
+{
+    osg::StateSet* ss = geode.getStateSet();
+    if (ss) addStateSet(ss);
+    for(int i=0;i<geode.getNumDrawables();++i)
+    {
+        ss = geode.getDrawable(i)->getStateSet();
+        if (ss) addStateSet(ss);
+    }
+}
+
+void OptimizeStateVisitor::optimize()
+{
+    osg::notify(osg::INFO) << "Num of StateSet="<<_statesets.size()<<endl;
+
+    // create map from state attributes to stateset which contain them.
+    typedef std::map<osg::StateAttribute*,StateSetList> AttributeToStateSetMap;
+    AttributeToStateSetMap _attributeToStateSetMap;
+
+    // NOTE will need to track state attribute override value too.
+
+    for(StateSetList::iterator sitr=_statesets.begin();
+        sitr!=_statesets.end();
+        ++sitr)
+    {
+        osg::StateSet::AttributeList& attributes = (*sitr)->getAttributeList();
+        for(osg::StateSet::AttributeList::iterator aitr= attributes.begin();
+            aitr!=attributes.end();
+            ++aitr)
+        {
+            _attributeToStateSetMap[aitr->second.first.get()].insert(*sitr);
+        }
+    }
+
+    if (_attributeToStateSetMap.size()<2)
+    {
+        osg::notify(osg::INFO) << "Too few state attributes to optimize."<<endl;
+        return;
+    }
+
+    // create unique set of state attribute pointers.
+    typedef std::vector<osg::StateAttribute*> AttributeList;
+    AttributeList _attributeList;
+
+    for(AttributeToStateSetMap::iterator aitr=_attributeToStateSetMap.begin();
+        aitr!=_attributeToStateSetMap.end();
+        ++aitr)
+    {
+        _attributeList.push_back(aitr->first);
+    }
+
+    // sort the attributes so that equal attributes sit along side each
+    // other.
+    std::sort(_attributeList.begin(),_attributeList.end(),LessAttributeFunctor());
+
+
+    osg::notify(osg::INFO) << "state attribute list"<<endl;
+    for(AttributeList::iterator aaitr = _attributeList.begin();
+        aaitr!=_attributeList.end();
+        ++aaitr)
+    {
+        osg::notify(osg::INFO) << "    "<<*aaitr << "  "<<(*aaitr)->className()<<endl;
+    }
+
+    osg::notify(osg::INFO) << "searching for duplicates"<<endl;
+    // find the duplicates.
+    AttributeList::iterator first_unique = _attributeList.begin();
+    AttributeList::iterator current = first_unique; ++current;
+    for(; current!=_attributeList.end();++current)
+    {
+        if (**current==**first_unique)
+        {
+            osg::notify(osg::INFO) << "    found duplicate "<<(*current)->className()<<"  first="<<*first_unique<<"  current="<<*current<<endl;
+            StateSetList& statesetlist = _attributeToStateSetMap[*current];
+            for(StateSetList::iterator sitr=statesetlist.begin();
+                sitr!=statesetlist.end();
+                ++sitr)
+            {
+                osg::notify(osg::INFO) << "       replace duplicate "<<*current<<" with "<<*first_unique<< endl;
+                osg::StateSet* stateset = *sitr;
+                stateset->setAttribute(*first_unique);
+            }
+        }
+        else first_unique = current;
+    }
+
+}