From c71e2100ecc8b374bb3849cb0dbbc053083df547 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Sun, 4 Jan 2004 22:28:37 +0000
Subject: [PATCH] Experiments at fixing seam handling.

---
 src/osgPlugins/txp/TXPSeamLOD.cpp  | 52 ++++++++++++++++++++++++++----
 src/osgPlugins/txp/TXPTileNode.cpp | 27 ++++++++++++++--
 2 files changed, 69 insertions(+), 10 deletions(-)

diff --git a/src/osgPlugins/txp/TXPSeamLOD.cpp b/src/osgPlugins/txp/TXPSeamLOD.cpp
index 4e159959b..7b8d8b092 100644
--- a/src/osgPlugins/txp/TXPSeamLOD.cpp
+++ b/src/osgPlugins/txp/TXPSeamLOD.cpp
@@ -45,18 +45,56 @@ void TXPSeamLOD::traverse(osg::NodeVisitor& nv)
 {
     if (nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR && _children.size()==2)
     {
-        float distance = nv.getDistanceToEyePoint(_center,true);
-        if (distance<_mid)
+
+#if 1
+        osg::PagedLOD* pagedLOD = TileMapper::instance()->getPagedLOD(_neighbourTileX,_neighbourTileY, _neighbourTileLOD);
+        if (pagedLOD)
         {
-            // cap the lod's that can be used to what is available in the adjacent PagedLOD.
-            osg::PagedLOD* pagedLOD = TileMapper::instance()->getPagedLOD(_neighbourTileX,_neighbourTileY, _neighbourTileLOD);
-            if (pagedLOD && pagedLOD->getNumChildren()>1) getChild(1)->accept(nv);
-            else getChild(0)->accept(nv);
+
+            float distance = nv.getDistanceToEyePoint(_center,true);
+            distance = nv.getDistanceToEyePoint(pagedLOD->getCenter(),true);
+
+            //std::cout<<"distance to eye from center = "<<distance<<" min = "<< _min<<" mid = "<< _mid << " max = "<<_max<<std::endl;
+            //std::cout<<"   TXPSeam::_center "<<_center<<"   PageLOD::_center "<<pagedLOD->getCenter()<<std::endl;
+            int numChildren = osg::minimum(getNumChildren(),pagedLOD->getNumChildren());
+            for(int i=numChildren-1;i>=0;--i)
+            {
+                //std::cout<<"   child "<<i<<" range = min "<<pagedLOD->getMinRange(i)<<" max = "<<pagedLOD->getMaxRange(i)<<std::endl;
+                if (distance<=pagedLOD->getMaxRange(i)) 
+                {
+                    getChild(i)->accept(nv);
+                    return;
+                }
+            }
         }
         else
         {
-            getChild(0)->accept(nv);
+            getChild(0)->accept(nv); // pick low res
         }
+#else
+        float distance = nv.getDistanceToEyePoint(_center,true);
+        if (distance<=_mid)
+        {
+            // cap the lod's that can be used to what is available in the adjacent PagedLOD.
+            
+            //std::cout<<"distance to eye from center = "<<distance<<" min = "<< _min<<" mid = "<< _mid << " max = "<<_max<<std::endl;
+            if (pagedLOD)
+            {
+                //std::cout<<"   in cull pagedLOD="<<pagedLOD<<" numChildren=="<<pagedLOD->getNumChildren()<<std::endl;
+                for(unsigned int i=0;i<pagedLOD->getNumChildren();++i)
+                {
+                    //std::cout<<"   child "<<i<<" range = min "<<pagedLOD->getMinRange(i)<<" max = "<<pagedLOD->getMaxRange(i)<<std::endl;
+                }
+            }
+            
+            if (pagedLOD && pagedLOD->getNumChildren()>1) getChild(1)->accept(nv); // pick high res
+            else getChild(0)->accept(nv); // pick low res as fallback
+        }
+        else
+        {
+            getChild(0)->accept(nv); // pick low res
+        }
+#endif
     }
     else
     {
diff --git a/src/osgPlugins/txp/TXPTileNode.cpp b/src/osgPlugins/txp/TXPTileNode.cpp
index 04daaa402..30f6cda23 100644
--- a/src/osgPlugins/txp/TXPTileNode.cpp
+++ b/src/osgPlugins/txp/TXPTileNode.cpp
@@ -125,10 +125,31 @@ osg::Node* TXPTileNode::seamReplacement(osg::Node* child,int x, int y, int level
                     }
                 }
             
-                TXPSeamLOD* seam = new TXPSeamLOD(x,y,level,lod1->getCenter(),lod2->getMinRange(0),lod2->getMaxRange(0),lod1->getMaxRange(0));
+ //                std::cout<<"seamReplacement lod1 min="<<lod1->getMinRange(0)<<" max="<<lod1->getMaxRange(0)<<std::endl;
+//                 std::cout<<"                lod2 min="<<lod2->getMinRange(0)<<" max="<<lod2->getMaxRange(0)<<std::endl;
+                
+                if (lod1->getMaxRange(0)<lod2->getMaxRange(0))
+                {
+//                     std::cout<<"   lod1 is high res, lod2 is low res."<<std::endl;
+                }
+                else if (lod1->getMaxRange(0)==lod2->getMaxRange(0))
+                {
+//                     std::cout<<"   lod1 and lod2 range equal. ****************"<<std::endl;
+                    // don't replace with seam LOD node, leave as a standard LOD.
+                    return 0;
+                }
+                else
+                {
+//                     std::cout<<"   lod1 is low res, lod2 is high res. --------------"<<std::endl;
+                    // don't replace with seam LOD node, leave as a standard LOD
+                    return 0;
+                }
+                
+            
+                TXPSeamLOD* seam = new TXPSeamLOD(x,y,level,lod1->getCenter(),lod1->getMinRange(0),lod1->getMaxRange(0),lod2->getMaxRange(0));
                 seam->setArchive(_archive);
-                seam->addChild(lod1->getChild(0));
-                seam->addChild(lod2->getChild(0));
+                seam->addChild(lod1->getChild(0)); // high res
+                seam->addChild(lod2->getChild(0)); // low res
                 return seam;
             }
         }