//C++ header - Open Scene Graph Simulation - Copyright (C) 1998-2002 Robert Osfield
// Distributed under the terms of the GNU General Public License (GPL)
// as published by the Free Software Foundation.
//
// All software using osgSim must be GPL'd or excempted via the 
// purchase of the Open Scene Graph Professional License (OSGPL)
// for further information contact robert@openscenegraph.com.

#include <osgSim/LightPointNode>

#include "LightPointDrawable.h"

#include <osg/Timer>
#include <osg/BoundingBox>
#include <osg/BlendFunc>
#include <osg/Material>

#include <osgUtil/CullVisitor>

#include <typeinfo>

using namespace osgSim;

LightPointNode::LightPointNode()
{
}

/** Copy constructor using CopyOp to manage deep vs shallow copy.*/
LightPointNode::LightPointNode(const LightPointNode& lpn,const osg::CopyOp& copyop):
    osg::Node(lpn,copyop),
    _lightPointList(lpn._lightPointList)
{
}

unsigned int LightPointNode::addLightPoint(const LightPoint& lp)
{
    unsigned int num = _lightPointList.size();
    _lightPointList.push_back(lp);
    dirtyBound();
    return num;
}

void LightPointNode::removeLightPoint(unsigned int pos)
{
    if (pos<_lightPointList.size())
    {
        _lightPointList.erase(_lightPointList.begin()+pos);
        dirtyBound();
    }
    dirtyBound();
}

void LightPointNode::removeLightPoints(LightPointList::iterator start,LightPointList::iterator end)
{
    _lightPointList.erase(start,end);
}

bool LightPointNode::computeBound() const
{
    _bsphere.init();
    _bbox.init();


    LightPointList::const_iterator itr;
    for(itr=_lightPointList.begin();
        itr!=_lightPointList.end();
        ++itr)
    {
        _bbox.expandBy(itr->_position);
    }


    _bsphere.set(_bbox.center(),0.0f);
    
    for(itr=_lightPointList.begin();
        itr!=_lightPointList.end();
        ++itr)
    {
        _bsphere.expandRadiusBy(itr->_position);
    }

    _bsphere_computed=true;
    return true;
}


void LightPointNode::traverse(osg::NodeVisitor& nv)
{
    //#define USE_TIMER
    #ifdef USE_TIMER
    osg::Timer timer;
    osg::Timer_t t1=0,t2=0,t3=0,t4=0,t5=0,t6=0,t7=0,t8=0;
    #endif

    
#ifdef USE_TIMER
    t1 = timer.tick();
#endif

    osgUtil::CullVisitor* cv = NULL;
    if (typeid(nv)==typeid(osgUtil::CullVisitor))
    {
        cv = static_cast<osgUtil::CullVisitor*>(&nv);
    }
    
#ifdef USE_TIMER
    t2 = timer.tick();
#endif
    

    // should we disabled small feature culling here?
    if (cv /*&& !cv->isCulled(_bbox)*/)
    {
    
        osg::Matrix matrix = cv->getModelViewMatrix();
        osg::Matrix& projection = cv->getProjectionMatrix();
        osgUtil::RenderGraph* rg = cv->getCurrentRenderGraph();

        if (rg->leaves_empty())
        {
            // this is first leaf to be added to RenderGraph
            // and therefore should not already know to current render bin,
            // so need to add it.
            cv->getCurrentRenderBin()->addRenderGraph(rg);
        }
        
#ifdef USE_TIMER
        t3 = timer.tick();
#endif


        LightPointDrawable* drawable = NULL;
        osg::Referenced* object = rg->getUserData();
        if (object)
        {
            if (typeid(*object)==typeid(LightPointDrawable))
            {
                // resuse the user data attached to the render graph.
                drawable = static_cast<LightPointDrawable*>(object);

            }
            else
            {
                // will need to replace UserData.
                osg::notify(osg::WARN) << "Warning: Replacing osgUtil::RenderGraph::_userData to support osgSim::LightPointNode, may have undefined results."<<std::endl;
            }
        }

        if (!drawable)
        {
            // set it for the frst time.
            drawable = osgNew LightPointDrawable;
            rg->setUserData(drawable);
            
            if (cv->getFrameStamp())
            {
                drawable->setReferenceTime(cv->getFrameStamp()->getReferenceTime());
            }
        }

        // search for a drawable in the RenderLead list equal to the attached the one attached to RenderGraph user data
        // as this will be our special light point drawable.
        osgUtil::RenderGraph::LeafList::iterator litr;
        for(litr = rg->_leaves.begin();
            litr != rg->_leaves.end() && (*litr)->_drawable!=drawable;
            ++litr)
        {}
        
        if (litr == rg->_leaves.end())
        {
            // havn't found the drawable added in the RenderLeaf list, there this my be the 
            // first time through LightPointNode in this frame, so need to add drawable into the RenderGraph RenderLeaf list
            // and update its time signatures.

            drawable->reset();
            rg->addLeaf(osgNew osgUtil::RenderLeaf(drawable,&projection,NULL,FLT_MAX));

            // need to update the drawable's frame count.
            if (cv->getFrameStamp())
            {
                drawable->updateReferenceTime(cv->getFrameStamp()->getReferenceTime());
            }

        }

#ifdef USE_TIMER
        t4 = timer.tick();
#endif


#ifdef USE_TIMER
        t7 = timer.tick();
#endif

        cv->updateCalculatedNearFar(matrix,_bbox);
        
        
        const float minimumIntensity = 1.0f/256.0f;
        const osg::Vec3 eyePoint = cv->getEyeLocal();
        
        double time=drawable->getReferenceTime();
        double timeInterval=drawable->getReferenceTimeInterval();
        
        const osg::Polytope clipvol(cv->getModelViewCullingStack().back()->getFrustum());
        const bool computeClipping = false;//(clipvol.getCurrentMask()!=0);

        //LightPointDrawable::ColorPosition cp;
        for(LightPointList::iterator itr=_lightPointList.begin();
            itr!=_lightPointList.end();
            ++itr)
        {
            const LightPoint& lp = *itr;
	    
	    if (!lp._on) continue;
	    
            const osg::Vec3& position = lp._position;
            
            // skip light point if it is not contianed in the view frustum.
            if (computeClipping && !clipvol.contains(position)) continue;
                        
            // delta vector between eyepoint and light point.
            osg::Vec3 dv(eyePoint-position);
            
            float intensity = lp._intensity;
            
            // slip light point if it is intensity is 0.0 or negative.
            if (intensity<=minimumIntensity) continue;

            osg::Vec4 color = lp._color;

            // check the sector.
            if (lp._sector.valid())
            {
                intensity *= (*lp._sector)(dv);
            
                // slip light point if it is intensity is 0.0 or negative.
                if (intensity<=minimumIntensity) continue;
                
            }
            
            // temporary accounting of intensity.
            //color *= intensity;

            // check the blink sequence.
            if (lp._blinkSequence.valid())
            {
                osg::Vec4 bs = lp._blinkSequence->color(time,timeInterval);
                color[0] *= bs[0];
                color[1] *= bs[1];
                color[2] *= bs[2];
                color[3] *= bs[3];
            }
            
            // if alpha value is less than the min intentsive then skip
            if (color[3]<=minimumIntensity) continue;

            float pixelSize = cv->pixelSize(position,lp._radius);

//            cout << "pixelsize = "<<pixelSize<<endl;
            
            // adjust pixel size to account for intensity.
            if (intensity!=1.0) pixelSize *= sqrt(intensity);
            
            osg::Vec3 xpos(position*matrix);
            if (pixelSize<1.0f)
            {
                // need to use alpha blending...
                //color[3] = pixelSize;
                color[3] *= osg::square(pixelSize);

                if (color[3]<=minimumIntensity) continue;

                drawable->addBlendedLightPoint(0, xpos,color);
            }
            else if (pixelSize<lp._maxPixelSize)
            {

                unsigned int lowerBoundPixelSize = (unsigned int)pixelSize;
                //float remainder = pixelSize-(float)lowerBoundPixelSize;
                float remainder = osg::square(pixelSize-(float)lowerBoundPixelSize);
                float alpha = color[3];
//                color[3] = alpha*(1.0f-remainder);
                drawable->addBlendedLightPoint(lowerBoundPixelSize-1, xpos,color);

//                 //color[3] = osg::square(remainder);
                color[3] = alpha*remainder;
                drawable->addBlendedLightPoint(lowerBoundPixelSize, xpos,color);
            }
            else // use a billboard geometry.
            {
                drawable->addOpaqueLightPoint((unsigned int)(lp._maxPixelSize-1.0), xpos,color);
            }
        }
        
#ifdef USE_TIMER
        t8 = timer.tick();
#endif
               
    }
#ifdef USE_TIMER
    cout << "compute"<<endl;
    cout << "  t2-t1="<<t2-t1<<endl;
    cout << "  t4-t3="<<t4-t3<<endl;
    cout << "  t6-t5="<<t6-t5<<endl;
    cout << "  t8-t7="<<t8-t7<<endl;
    cout << "_lightPointList.size()="<<_lightPointList.size()<<endl;
    cout << "  t8-t7/size = "<<(float)(t8-t7)/(float)_lightPointList.size()<<endl;
#endif
}