/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2005 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 OSGPARTICLE_PRECIPITATIONEFFECT
#define OSGPARTICLE_PRECIPITATIONEFFECT

#include <osg/Group>
#include <osg/BoundingBox>
#include <osg/ClearNode>
#include <osg/Fog>
#include <osg/Geometry>

#include <osgUtil/CullVisitor>

#include <osgParticle/Export>

namespace osgParticle
{
    struct OSGPARTICLE_EXPORT PrecipitationParameters : public osg::Referenced
    {
        PrecipitationParameters();

        void rain (float intensity);

        void snow(float intensity);

        osg::Vec3           wind;
        osg::BoundingBox    boundingBox;
        float               particleVelocity;
        float               particleSize;
        osg::Vec4           particleColour;
        float               particleDensity;
        float               cellSizeX;
        float               cellSizeY;
        float               cellSizeZ;
        float               nearTransition;
        float               farTransition;
        float               fogExponent;
        float               fogDensity;
        float               fogEnd;
        osg::Vec4           fogColour;
        osg::Vec4           clearColour;
        bool                useFarLineSegments;
    };

    class OSGPARTICLE_EXPORT PrecipitationEffect : public osg::Group
    {
    public:
    
        PrecipitationEffect();
        PrecipitationEffect(const PrecipitationEffect& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY);

        virtual const char* libraryName() const { return "osgParticle"; }
        virtual const char* className() const { return "PrecipitationEffect"; }
        virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const PrecipitationEffect*>(obj) != 0; }
        virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) { nv.pushOntoNodePath(this); nv.apply(*this); nv.popFromNodePath(); } }

        virtual void traverse(osg::NodeVisitor& nv);

        void setParameters(PrecipitationParameters* parameters);
        
        PrecipitationParameters* getParameters() { return _parameters.get(); }
        
        const PrecipitationParameters* getParameters() const { return _parameters.get(); }
        
        void compileGLObjects(osg::State& state) const;

        void update();

    protected:
    
        virtual ~PrecipitationEffect() {}
        
        void createGeometry(unsigned int numParticles, 
                            osg::Geometry* quad_geometry, 
                            osg::Geometry* line_geometry,
                            osg::Geometry* point_geometry);
                    
        void setUpGeometries(unsigned int numParticles);

        class OSGPARTICLE_EXPORT PrecipitationDrawable : public osg::Drawable
        {
        public:

            PrecipitationDrawable();
            PrecipitationDrawable(const PrecipitationDrawable& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY);

            META_Object(osgParticle, PrecipitationDrawable);

            virtual bool supports(const osg::PrimitiveFunctor&) const { return false; }
            virtual void accept(osg::PrimitiveFunctor&) const {}
            virtual bool supports(const osg::PrimitiveIndexFunctor&) const { return false; }
            virtual void accept(osg::PrimitiveIndexFunctor&) const {}

            void setRequiresPreviousMatrix(bool flag) { _requiresPreviousMatrix = flag; }
            bool getRequiresPreviousMatrix() const { return _requiresPreviousMatrix; }

            void setGeometry(osg::Geometry* geom) { _geometry = geom; }
            osg::Geometry* getGeometry() { return _geometry.get(); }
            const osg::Geometry* getGeometry() const { return _geometry.get(); }

            virtual void drawImplementation(osg::State& state) const;

            struct Cell
            {
                Cell(int in_i, int in_j, int in_k):
                    i(in_i), j(in_j), k(in_k) {}


                inline bool operator == (const Cell& rhs) const
                {
                    return i==rhs.i && j==rhs.j && k==rhs.k;
                }

                inline bool operator != (const Cell& rhs) const
                {
                    return i!=rhs.i || j!=rhs.j || k!=rhs.k;
                }

                inline bool operator < (const Cell& rhs) const
                {
                    if (i<rhs.i) return true;
                    if (i>rhs.i) return false;
                    if (j<rhs.j) return true;
                    if (j>rhs.j) return false;
                    if (k<rhs.k) return true;
                    if (k>rhs.k) return false;
                    return false;
                }

                int i;
                int j;
                int k;
            };

            typedef std::pair<osg::Matrix, float>  MatrixStartTimePair;

            typedef std::map< Cell, MatrixStartTimePair >  CellMatrixMap;

            CellMatrixMap& getCurrentCellMatrixMap() { return _currentCellMatrixMap; }
            CellMatrixMap& getPreviousCellMatrixMap() { return _previousCellMatrixMap; }

            inline void newFrame()
            {
                _previousCellMatrixMap.swap(_currentCellMatrixMap);
                _currentCellMatrixMap.clear();
            }

        protected:

            virtual ~PrecipitationDrawable() {}

            bool _requiresPreviousMatrix;

            osg::ref_ptr<osg::Geometry> _geometry;

            mutable CellMatrixMap _currentCellMatrixMap;
            mutable CellMatrixMap _previousCellMatrixMap;

        };

        struct PrecipitationDrawableSet
        {
            osg::ref_ptr<PrecipitationDrawable> _quadPrecipitationDrawable;
            osg::ref_ptr<PrecipitationDrawable> _linePrecipitationDrawable;
            osg::ref_ptr<PrecipitationDrawable> _pointPrecipitationDrawable;
        };
        
        void cull(PrecipitationDrawableSet& pds, osgUtil::CullVisitor* cv) const;
        bool build(const osg::Vec3 eyeLocal, int i, int j, int k, float startTime, PrecipitationDrawableSet& pds, osg::Polytope& frustum, osgUtil::CullVisitor* cv) const;

        osg::ref_ptr<PrecipitationParameters> _parameters;

        // elements for the subgraph
        osg::ref_ptr<osg::ClearNode>    _clearNode;
        osg::ref_ptr<osg::Fog>          _fog;


        typedef std::pair< osg::NodeVisitor*, osg::NodePath > ViewIdenitifier;
        typedef std::map< ViewIdenitifier, PrecipitationDrawableSet >  ViewDrawableMap;

        OpenThreads::Mutex _mutex;
        ViewDrawableMap _viewDrawableMap;
        
        osg::ref_ptr<osg::StateSet>     _precipitationStateSet;
        
        osg::ref_ptr<osg::Geometry> _quadGeometry;
        osg::ref_ptr<osg::StateSet> _quadStateSet;

        osg::ref_ptr<osg::Geometry> _lineGeometry;
        osg::ref_ptr<osg::StateSet> _lineStateSet;

        osg::ref_ptr<osg::Geometry> _pointGeometry;
        osg::ref_ptr<osg::StateSet> _pointStateSet;


        float       _period;
        osg::Vec3   _origin;
        osg::Vec3   _du;
        osg::Vec3   _dv;
        osg::Vec3   _dw;
        osg::Vec3   _inverse_du;
        osg::Vec3   _inverse_dv;
        osg::Vec3   _inverse_dw;

    };

}

#endif