void TXPPagedLOD::traverse(osg::NodeVisitor& nv)
{
//TileMapper* tileMapper = dynamic_cast<TileMapper*>(nv.getUserData());
//Modified by Brad Anderegg (May-27-08) because the black listing process appears to make tiles switch lods
//when they clearly shouldnt, in the worst cases a tile will page out that is right in front of you.
bool forceUseOfFirstChild = /*tileMapper ? (tileMapper->isNodeBlackListed(this)) :*/ false;
double timeStamp = nv.getFrameStamp()?nv.getFrameStamp()->getReferenceTime():0.0;
bool updateTimeStamp = nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR;
unsigned int frameNumber = nv.getFrameStamp()?nv.getFrameStamp()->getFrameNumber():0;
// set the frame number of the traversal so that external nodes can find out how active this
// node is.
if (nv.getFrameStamp() &&
nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR)
{
setFrameNumberOfLastTraversal(nv.getFrameStamp()->getFrameNumber());
}
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;
_perRangeDataList[i]._frameNumber=frameNumber;
}
_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,
nv.getNodePath(),
priority,
nv.getFrameStamp(),
_perRangeDataList[numChildren]._databaseRequest);
}
}
break;
}
default:
break;
}
}
