OpenSceneGraph/src/osgPlugins/txp/TXPPagedLOD.cpp

#include "TileMapper.h"
#include "TXPPagedLOD.h"
using namespace txp;

TXPPagedLOD::TXPPagedLOD():
    osg::PagedLOD()
{
}

TXPPagedLOD::TXPPagedLOD(const TXPPagedLOD& plod,const osg::CopyOp& copyop):
    osg::PagedLOD(plod,copyop),
    _tileIdentifier(plod._tileIdentifier)
{
}

TXPPagedLOD::~TXPPagedLOD()
{
}

void TXPPagedLOD::traverse(osg::NodeVisitor& nv)
{

    TileMapper* tileMapper = dynamic_cast<TileMapper*>(nv.getUserData());
    bool forceUseOfFirstChild = tileMapper ? (tileMapper->isNodeBlackListed(this)) : false;

    double timeStamp = nv.getFrameStamp()?nv.getFrameStamp()->getReferenceTime():0.0;
    bool updateTimeStamp = nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR;

    switch(nv.getTraversalMode())
    {
        case(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN):
            std::for_each(_children.begin(),_children.end(),osg::NodeAcceptOp(nv));
            break;
        case(osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN):
        {
            float distance = nv.getDistanceToEyePoint(getCenter(),true);

            int lastChildTraversed = -1;
            bool needToLoadChild = false;
            
            unsigned maxRangeSize = _rangeList.size();
            if (maxRangeSize!=0 && forceUseOfFirstChild) maxRangeSize=1;
            
            for(unsigned int i=0;i<maxRangeSize;++i)
            {    
                if (forceUseOfFirstChild || _rangeList[i].first<=distance && distance<_rangeList[i].second)
                {
                    if (i<_children.size())
                    {
                        if (updateTimeStamp) _perRangeDataList[i]._timeStamp=timeStamp;

                        //std::cout<<"PagedLOD::traverse() - Selecting child "<<i<<std::endl;
                        _children[i]->accept(nv);
                        lastChildTraversed = (int)i;
                    }
                    else
                    {
                        needToLoadChild = true;
                    }
                }
            }
            
            if (needToLoadChild)
            {
                unsigned int numChildren = _children.size();
                
                //std::cout<<"PagedLOD::traverse() - falling back "<<std::endl;
                // select the last valid child.
                if (numChildren>0 && ((int)numChildren-1)!=lastChildTraversed)
                {
                    //std::cout<<"    to child "<<numChildren-1<<std::endl;
                    if (updateTimeStamp) _perRangeDataList[numChildren-1]._timeStamp=timeStamp;
                    _children[numChildren-1]->accept(nv);
                }
                
                // now request the loading of the next unload child.
                if (nv.getDatabaseRequestHandler() && numChildren<_perRangeDataList.size())
                {
                    // compute priority from where abouts in the required range the distance falls.
                    float priority = (_rangeList[numChildren].second-distance)/(_rangeList[numChildren].second-_rangeList[numChildren].first);
                    
                    // modify the priority according to the child's priority offset and scale.
                    priority = _perRangeDataList[numChildren]._priorityOffset + priority * _perRangeDataList[numChildren]._priorityScale;

                    //std::cout<<"    requesting child "<<_fileNameList[numChildren]<<" priotity = "<<priority<<std::endl;
                    nv.getDatabaseRequestHandler()->requestNodeFile(_perRangeDataList[numChildren]._filename,this,priority,nv.getFrameStamp());
                }
                
                
            }
            
            
           break;
        }
        default:
            break;
    }
}