Added osg::PagedLOD and osgProducer::DatabasePager class, and linked up osgProducer::Viewer

to manage the pager.

src/osg/PagedLOD.cpp

@@ -0,0 +1,143 @@
+#include <osg/PagedLOD>
+
+using namespace osg;
+
+PagedLOD::PagedLOD(const PagedLOD& plod,const CopyOp& copyop):
+    LOD(plod,copyop)
+{
+}
+
+void PagedLOD::traverse(NodeVisitor& nv)
+{
+
+    double timeStamp = nv.getFrameStamp()?nv.getFrameStamp()->getReferenceTime():0.0;
+    bool updateTimeStamp = nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR;
+
+    switch(nv.getTraversalMode())
+    {
+        case(NodeVisitor::TRAVERSE_ALL_CHILDREN):
+            std::for_each(_children.begin(),_children.end(),NodeAcceptOp(nv));
+            break;
+        case(NodeVisitor::TRAVERSE_ACTIVE_CHILDREN):
+        {
+            float distance = nv.getDistanceToEyePoint(getCenter(),true);
+            
+            // first check to see if any children can be directly traversed.
+            unsigned int numChildren = osg::minimum(_children.size(),numChildren=_rangeList.size());
+            bool childTraversed = false;
+            for(unsigned int i=0;i<numChildren;++i)
+            {    
+                if (_rangeList[i].first<=distance && distance<_rangeList[i].second)
+                {
+                    if (updateTimeStamp) _timeStampList[i]=timeStamp;
+
+                    //std::cout<<"PagedLOD::traverse() - Selecting child "<<i<<std::endl;
+                    _children[i]->accept(nv);
+                    childTraversed = true;
+                }
+            }
+            
+            if (!childTraversed)
+            {
+                //std::cout<<"PagedLOD::traverse() - falling back "<<std::endl;
+                // select the last valid child.
+                if (numChildren>0)
+                {
+                    //std::cout<<"    to child "<<numChildren-1<<std::endl;
+                    if (updateTimeStamp) _timeStampList[numChildren-1]=timeStamp;
+                    _children[numChildren-1]->accept(nv);
+                }
+                
+                // now request the loading of the next unload child.
+                if (nv.getDatabaseRequestHandler() && numChildren<_fileNameList.size())
+                {
+                    //std::cout<<"    requesting child "<<_fileNameList[numChildren]<<std::endl;
+                    nv.getDatabaseRequestHandler()->requestNodeFile(_fileNameList[numChildren],this);
+                }
+                
+                
+            }
+            
+            
+           break;
+        }
+        default:
+            break;
+    }
+}
+
+bool PagedLOD::addChild( Node *child )
+{
+    if (LOD::addChild(child))
+    {
+        if (_children.size()>_fileNameList.size()) _fileNameList.resize(_children.size());
+        if (_children.size()>_timeStampList.size()) _timeStampList.resize(_children.size(),0);
+        return true;
+    }
+    return false;
+}
+
+bool PagedLOD::addChild(Node *child, float min, float max)
+{
+    if (LOD::addChild(child,min,max))
+    {
+        if (_children.size()>_fileNameList.size()) _fileNameList.resize(_children.size());
+        if (_children.size()>_timeStampList.size()) _timeStampList.resize(_children.size(),0.0);
+
+        return true;
+    }
+    return false;
+}
+
+
+bool PagedLOD::addChild(Node *child, float min, float max,const std::string& filename)
+{
+    if (LOD::addChild(child,min,max))
+    {
+        if (_children.size()>_fileNameList.size()) _fileNameList.resize(_children.size());
+        if (_children.size()>_timeStampList.size()) _timeStampList.resize(_children.size(),0.0);
+
+        _fileNameList[_children.size()-1] = filename;
+
+        return true;
+    }
+    return false;
+}
+
+bool PagedLOD::removeChild( Node *child )
+{
+    // find the child's position.
+    unsigned int pos=getChildIndex(child);
+    if (pos==_children.size()) return false;
+    
+    _rangeList.erase(_rangeList.begin()+pos);
+    _fileNameList.erase(_fileNameList.begin()+pos);
+    _timeStampList.erase(_timeStampList.begin()+pos);
+    
+    return Group::removeChild(child);    
+}
+
+void PagedLOD::setFileName(unsigned int childNo, const std::string& filename)
+{
+    if (childNo>=_fileNameList.size()) _fileNameList.resize(childNo+1);
+    _fileNameList[childNo] = filename;
+}
+
+void PagedLOD::setTimeStamp(unsigned int childNo, double timeStamp)
+{
+    if (childNo>=_timeStampList.size()) _timeStampList.resize(childNo+1,0.0);
+    _timeStampList[childNo] = timeStamp;
+}
+
+void PagedLOD::removeExpiredChildren(double expiryTime)
+{
+    for(unsigned int i=_children.size();i>0;)
+    {
+        --i;
+        if (!_fileNameList[i].empty() && _timeStampList[i]<expiryTime)
+        {
+            //std::cout<<"Removing child "<<_children[i].get()<<std::endl;
+            Group::removeChild(_children[i].get());
+        }
+    }
+}