/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSG_KDTREE
#define OSG_KDTREE 1

#include <osg/Shape>
#include <osg/Geometry>

namespace osg
{

/** Implementation of a kdtree for Geometry leaves, to enable fast intersection tests.*/
class OSG_EXPORT KdTree : public osg::Shape 
{
    public:
    
        
        KdTree() {}
        
        KdTree(const KdTree& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
            Shape(rhs,copyop) {}

        META_Shape(osg, KdTree)
        
        /** Build the kdtree from the specified source geometry object.
          * retun true on success. */ 
        virtual bool build(osg::Geometry* geometry);
        
        
        struct LineSegmentIntersection
        {
            LineSegmentIntersection():
                ratio(-1.0),
                primitiveIndex(0) {}

            bool operator < (const LineSegmentIntersection& rhs) const { return ratio < rhs.ratio; }

            typedef std::vector<unsigned int>   IndexList;
            typedef std::vector<double>         RatioList;

            double                          ratio;
            osg::Vec3d                      intersectionPoint;
            osg::Vec3                       intersectionNormal;
            IndexList                       indexList;
            RatioList                       ratioList;
            unsigned int                    primitiveIndex;
        };        
        

        typedef std::multiset<LineSegmentIntersection> LineSegmentIntersections;
        
        /** compute the intersection of a line segment and the kdtree, return true if an intersection has been found.*/
        virtual bool intersect(const osg::Vec3& start, const osg::Vec3& end, LineSegmentIntersections& intersections);



        typedef int value_type;
        typedef std::vector< value_type >   Indices;

        struct KDNode
        {
            KDNode():
                first(0),
                second(0) {}

            KDNode(value_type f, value_type s):
                first(f),
                second(s) {}

            value_type first;    
            value_type second;

            osg::BoundingBox bb;
        };


        struct KDLeaf
        {
            KDLeaf():
                first(0),
                second(0) {}

            KDLeaf(value_type f, value_type s):
                first(f),
                second(s) {}

            value_type first;    
            value_type second;

            osg::BoundingBox bb;
        };

        struct Triangle
        {
            Triangle(unsigned int p1, unsigned int p2, unsigned int p3):
                _p1(p1), _p2(p2), _p3(p3) {}

            bool operator < (const Triangle& rhs) const
            {
                if (_p1<rhs._p1) return true;
                if (_p1>rhs._p1) return false;
                if (_p2<rhs._p2) return true;
                if (_p2>rhs._p2) return false;
                return _p3<rhs._p3;
            }

            unsigned int _p1;
            unsigned int _p2;
            unsigned int _p3;    
        };


};

class OSG_EXPORT KdTreeBuilder : public osg::NodeVisitor
{
    public:
    
        KdTreeBuilder();
    
        void apply(osg::Geode& geode);
    
        osg::ref_ptr<osg::KdTree> _kdTreePrototype;
        
        unsigned int _maxNumLevels;
        unsigned int _targetNumTrianglesPerLeaf;
        
        unsigned int _numVerticesProcessed;
        
    protected:
    
        virtual ~KdTreeBuilder() {}
        
};

}

#endif