Added prelimnary KdTree data structure and automatic kdtree build support

into osgDB::Registry/osgTerrain so that newly created subgraphs can have 
KdTree built on all osg::Geometry automatically on load/creation.

src/osg/CMakeLists.txt

@@ -72,6 +72,7 @@ SET(LIB_PUBLIC_HEADERS
     ${HEADER_PATH}/Image
     ${HEADER_PATH}/ImageStream
     ${HEADER_PATH}/io_utils
+    ${HEADER_PATH}/KdTree
     ${HEADER_PATH}/Light
     ${HEADER_PATH}/LightModel
     ${HEADER_PATH}/LightSource
@@ -228,6 +229,7 @@ ADD_LIBRARY(${LIB_NAME}
     Hint.cpp
     Image.cpp
     ImageStream.cpp
+    KdTree.cpp
     LOD.cpp
     Light.cpp
     LightModel.cpp

src/osg/KdTree.cpp

@@ -0,0 +1,67 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osg/KdTree>
+#include <osg/Geode>
+
+using namespace osg;
+
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// KdTree
+
+bool KdTree::build(osg::Geometry* geometry)
+{
+    osg::notify(osg::NOTICE)<<"KdTree::build("<<geometry<<")"<<std::endl;
+    return true;
+}
+
+bool KdTree::intersect(const osg::Vec3& start, const osg::Vec3& end, LineSegmentIntersections& intersections)
+{
+    return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// KdTreeBuilder
+KdTreeBuilder::KdTreeBuilder():
+    osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
+    _maxNumLevels(16),
+    _targetNumTrianglesPerLeaf(4),
+    _numVerticesProcessed(0)
+{            
+    _kdTreePrototype = new osg::KdTree;
+}
+
+
+void KdTreeBuilder::apply(osg::Geode& geode)
+{
+    for(unsigned int i=0; i<geode.getNumDrawables(); ++i)
+    {            
+
+        osg::Geometry* geom = geode.getDrawable(i)->asGeometry();
+        if (geom)
+        {
+            osg::KdTree* previous = dynamic_cast<osg::KdTree*>(geom->getShape());
+            if (previous) continue;
+
+            osg::ref_ptr<osg::KdTree> kdTree = dynamic_cast<osg::KdTree*>(_kdTreePrototype->cloneType());
+
+            if (kdTree->build(geom))
+            {
+                geom->setShape(kdTree.get());
+            }
+        }   
+    }
+}

src/osgDB/Registry.cpp

@@ -158,6 +158,17 @@ Registry::Registry()
     // comment out because it was causing problems under OSX - causing it to crash osgconv when constructing ostream in osg::notify().
     // notify(INFO) << "Constructing osg::Registry"<<std::endl;
 
+    _buildKdTreesHint = ReaderWriter::Options::NO_PREFERENCE;
+    _kdTreeBuilder = new osg::KdTreeBuilder;
+    
+    const char* kdtree_str = getenv("OSG_BUILD_KDTREES");
+    if (kdtree_str)
+    {
+        bool switchOff = (strcmp(kdtree_str, "off")==0 || strcmp(kdtree_str, "OFF")==0 || strcmp(kdtree_str, "Off")==0 );
+        if (switchOff) _buildKdTreesHint = ReaderWriter::Options::DO_NOT_BUILD_KDTREES;
+        else _buildKdTreesHint = ReaderWriter::Options::BUILD_KDTREES;
+    }
+
     _createNodeFromImage = false;
     _openingLibrary = false;
 
@@ -166,6 +177,8 @@ Registry::Registry()
     
     initFilePathLists();
 
+
+
     // register file extension alias.
     const char* flt_str = getenv("OSG_OPEN_FLIGHT_PLUGIN");
     if (flt_str)
@@ -388,7 +401,7 @@ void Registry::readCommandLine(osg::ArgumentParser& arguments)
 
     while(arguments.read("-O",value))
     {
-        setOptions(new osgDB::ReaderWriter::Options(value));
+        setOptions(new ReaderWriter::Options(value));
     }
 }
 

src/osgTerrain/GeometryTechnique.cpp

@@ -642,6 +642,15 @@ void GeometryTechnique::generateGeometry(Locator* masterLocator, const osg::Vec3
 
     //geometry->setUseDisplayList(false);
     geometry->setUseVertexBufferObjects(true);
+    
+    
+    if (osgDB::Registry::instance()->getBuildKdTreesHint()==osgDB::ReaderWriter::Options::BUILD_KDTREES &&
+        osgDB::Registry::instance()->getKdTreeBuilder())
+    {
+        //osg::notify(osg::NOTICE)<<"osgTerrain::GeometryTechnique::build kd tree"<<std::endl;
+        buffer._geode->accept(*(osgDB::Registry::instance()->getKdTreeBuilder()));
+        //osg::notify(osg::NOTICE)<<"after"<<std::endl;
+    }
 }
 
 void GeometryTechnique::applyColorLayers()