//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGUTIL_OPTIMIZER
#define OSGUTIL_OPTIMIZER

#include <osg/NodeVisitor>
#include <osg/Matrix>

#include <osgUtil/Export>

namespace osgUtil {

/** Insert impostor nodes into scene graph.
  * For example of usage see src/Demos/osgimpostor.
  */
  
class OSGUTIL_EXPORT Optimizer
{

    public:

        Optimizer() {}

        enum OptimizationOptions
        {
            FLATTEN_STATIC_TRANSFORMS = 0x1,
            REMOVE_REDUNDENT_NODES = 0x2,
            COMBINE_ADJACENT_LODS = 0x4,
            SHARE_DUPLICATE_STATE = 0x8,
            ALL_OPTIMIZATIONS = FLATTEN_STATIC_TRANSFORMS |
                                REMOVE_REDUNDENT_NODES |
                                COMBINE_ADJACENT_LODS |
                                SHARE_DUPLICATE_STATE
        };

        /** traverse the node and its subgraph with a series of optimization
          * visitors, specificied by the OptizationOptions.*/
        virtual void optimize(osg::Node* node, unsigned int options = ALL_OPTIMIZATIONS);


        
        /** Flatten Static Trasform nodes by applying their transform to the
          * geometry on the leaves of the scene graph, then removing the 
          * now redundent transforms.*/        
        class OSGUTIL_EXPORT FlattenStaticTransformsVisitor : public osg::NodeVisitor
        {
            public:

                typedef std::vector<osg::Matrix> MatrixStack;

                typedef std::set<osg::Transform*> TransformList;
                
                MatrixStack     _matrixStack;
                TransformList   _transformList;
                bool            _ignoreDynamicTransforms;

                FlattenStaticTransformsVisitor(bool ignoreDynamicTransforms=true):
                    osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
                    _ignoreDynamicTransforms(ignoreDynamicTransforms) {}

                virtual void apply(osg::Geode& geode);
                virtual void apply(osg::Billboard& billboard);
                virtual void apply(osg::LOD& lod);
                virtual void apply(osg::Transform& transform);

                void removeTransforms();

        };

        /** Remove rendundent nodes, such as groups with one single child.*/
        class OSGUTIL_EXPORT RemoveRedundentNodesVisitor : public osg::NodeVisitor
        {
            public:

                typedef std::set<osg::Node*> NodeList;
                NodeList                     _redundentNodeList;

                RemoveRedundentNodesVisitor():osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN) {}

                virtual void apply(osg::Group& group);
                
                void removeRedundentNodes();

        };

        /** Optimize the LOD groups, by combining adjacent LOD's which have
          * complementary ranges.*/
        class OSGUTIL_EXPORT CombineLODsVisitor : public osg::NodeVisitor
        {
            public:

                typedef std::set<osg::Group*>  GroupList;
                GroupList                      _groupList;

                CombineLODsVisitor():osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN) {}

                virtual void apply(osg::LOD& lod);

                void combineLODs();

        };
 
        /** Optimize State in the scene graph by removing duplicate state,
          * replacing it with shared instances, both for StateAttributes,
          * and whole StateSets.*/
        class OSGUTIL_EXPORT StateVisitor : public osg::NodeVisitor
        {
            public:

                /// default to traversing all children.
                StateVisitor() : osg::NodeVisitor(TRAVERSE_ALL_CHILDREN) {}

                /** empty visitor, make it ready for next traversal.*/        
                virtual void reset();

                virtual void apply(osg::Node& node);

                virtual void apply(osg::Geode& geode);

                void optimize();

            protected:

                void addStateSet(osg::StateSet* stateset,osg::Object* obj);

                typedef std::set<osg::Object*>              ObjectSet;
                typedef std::map<osg::StateSet*,ObjectSet>  StateSetMap;

                StateSetMap _statesets;

        };

};

};

#endif