#ifndef OSG_LOD
#define OSG_LOD 1

#include <osg/Switch>

#include <vector>

namespace osg {

/** LOD - Level Of Detail group node which allows switching between children
    depending on distance from eye point.
    Typical uses are for load balancing - objects further away from
    the eye point are rendered at a lower level of detail, and at times
    of high stress on the graphics pipeline lower levels of detail can
    also be chosen.
*/
class SG_EXPORT LOD : public Group
{
    public :
        LOD() {}

        virtual Object* clone() const { return new LOD(); }
        virtual bool isSameKindAs(Object* obj) { return dynamic_cast<LOD*>(obj)!=NULL; }
        virtual const char* className() const { return "LOD"; }
        virtual void accept(NodeVisitor& nv) { nv.apply(*this); }
        virtual void traverse(NodeVisitor& nv);
        
        /** Sets the value of range list element index to range which
            is a floating point distance specified in world coordinates.
            Range list automatically expands to accomodate values beyond
            the current getNumRanges().*/
        void setRange(unsigned int index, float range);
        /** pfLOD::getRange returns the range element index.*/
        float getRange(unsigned int index) { return _rangeList[index]; }
        /** returns the number of ranges currently set.*/
        int getNumRanges() { return _rangeList.size(); }

        /** Sets the object-space point which defines the center of the osg::LOD.  
            center is affected by any transforms in the hierarchy above the osg::LOD.*/
        void setCenter(const Vec3 &center) { _center = center; }
        /** return the LOD center point. */
        const Vec3& getCenter() { return _center; }


        /** return the child to traverse.
            Selected by the distance between the eye point in local
            coordinates and the LOD center, mutliplied by the bias.*/ 
        int evaluate(const Vec3& eye_local,float bias=1.0f);


    protected :
        virtual ~LOD() {}

        virtual bool readLocalData(Input& fr);
        virtual bool writeLocalData(Output& fw);

        typedef std::vector<float> RangeList;
        RangeList _rangeList;
        RangeList _rangeList2;

        Vec3 _center;

};

};

#endif