Added osg::CollectOccludersVisitor which is a helper class for finding active

occluder in the view frustum, to be used as pre cull traversal.

NEWS

@@ -10,6 +10,10 @@ OSG News (most significant items from ChangeLog)
 
     osgSim a seperate add-on library adds support for navigational light points.
     
+    osgGA (Gui Abstrabtion) library introduced to provide classes for adatping
+    different GUI toolkits to work with a standard set of manipulators for
+    modifying the scene, such as camera and state manipulators.
+    
     Support for NodeKits.
 
 

VisualStudio/osg/osg.dsp

@@ -133,6 +133,10 @@ SOURCE=..\..\src\osg\ColorMatrix.cpp
 # End Source File
 # Begin Source File
 
+SOURCE=..\..\src\osg\CollectOccludersVisitor.cpp
+# End Source File
+# Begin Source File
+
 SOURCE=..\..\src\osg\ConvexPlanerOccluder.cpp
 # End Source File
 # Begin Source File
@@ -429,6 +433,10 @@ SOURCE=..\..\Include\Osg\ColorMatrix
 # End Source File
 # Begin Source File
 
+SOURCE=..\..\Include\Osg\CollectOccludersVisitor
+# End Source File
+# Begin Source File
+
 SOURCE=..\..\Include\Osg\CopyOp
 # End Source File
 # Begin Source File

include/osg/CollectOccludersVisitor

@@ -0,0 +1,54 @@
+//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
+//Distributed under the terms of the GNU Library General Public License (LGPL)
+//as published by the Free Software Foundation.
+
+#ifndef OSG_COLLECTOCCLUDERSVISITOR
+#define OSG_COLLECTOCCLUDERSVISITOR 1
+
+#include <osg/NodeVisitor>
+#include <osg/CullStack>
+
+namespace osg {
+
+class SG_EXPORT CollectOccludersVisitor : public osg::NodeVisitor, public osg::CullStack
+{
+    public:
+
+
+        CollectOccludersVisitor();
+        virtual ~CollectOccludersVisitor();
+
+        virtual CollectOccludersVisitor* cloneType() const { return new CollectOccludersVisitor(); }
+
+        virtual void reset();
+
+        virtual void apply(osg::Node&);
+        virtual void apply(osg::Transform& node);
+        virtual void apply(osg::Projection& node);
+
+        virtual void apply(osg::Switch& node);
+        virtual void apply(osg::LOD& node);
+        virtual void apply(osg::OccluderNode& node);
+
+        typedef std::vector<ShadowVolumeOccluder> OccluderList;
+
+        OccluderList& getOccluderList() { return _occluderList; }
+        const OccluderList& getOccluderList() const { return _occluderList; }
+
+
+    protected:
+
+        /** prevent unwanted copy construction.*/
+        CollectOccludersVisitor(const CollectOccludersVisitor&):osg::NodeVisitor(),osg::CullStack() {}
+
+        /** prevent unwanted copy operator.*/
+        CollectOccludersVisitor& operator = (const CollectOccludersVisitor&) { return *this; }
+        
+        OccluderList _occluderList;
+
+};
+
+}
+
+#endif
+

include/osg/Node

@@ -141,6 +141,12 @@ class SG_EXPORT Node : public Object
           * note, return true only if no children have culling disabled, and the local _cullingActive flag is true.*/
         inline const bool isCullingActive() const { return _numChildrenWithCullingDisabled==0 && _cullingActive && _bsphere.isValid(); }
 
+        /** Get the number of Children of this node which are or have OccluderNode's.*/
+        inline const int getNumChildrenWithOccluderNodes() const { return _numChildrenWithOccluderNodes; }
+
+        
+        /** return true if this node is an OccluderNode or the subgraph below this node are OccluderNodes.*/
+        inline const bool containsOccluderNodes() const;
 
         /**
          * Set user data, data must be subclased from Referenced to allow
@@ -248,6 +254,9 @@ class SG_EXPORT Node : public Object
         int _numChildrenWithCullingDisabled;        
         void setNumChildrenWithCullingDisabled(const int num);
 
+        int _numChildrenWithOccluderNodes;        
+        void setNumChildrenWithOccluderNodes(const int num);
+
         osg::ref_ptr<Referenced> _userData;
 
         NodeMask _nodeMask;

src/osg/CollectOccludersVisitor.cpp

@@ -0,0 +1,42 @@
+#include <osg/CollectOccludersVisitor>
+
+using namespace osg;
+
+CollectOccludersVisitor::CollectOccludersVisitor()
+{
+}
+
+CollectOccludersVisitor::~CollectOccludersVisitor()
+{
+}
+
+void CollectOccludersVisitor::reset()
+{
+    CullStack::reset();
+}
+
+void CollectOccludersVisitor::apply(osg::Node&)
+{
+}
+
+void CollectOccludersVisitor::apply(osg::Transform& node)
+{
+}
+
+void CollectOccludersVisitor::apply(osg::Projection& node)
+{
+}
+
+void CollectOccludersVisitor::apply(osg::Switch& node)
+{
+}
+
+void CollectOccludersVisitor::apply(osg::LOD& node)
+{
+}
+
+void CollectOccludersVisitor::apply(osg::OccluderNode& node)
+{
+}
+
+

src/osg/Group.cpp

@@ -3,6 +3,7 @@
 #include <osg/Group>
 #include <osg/BoundingBox>
 #include <osg/Transform>
+#include <osg/OccluderNode>
 
 #include <algorithm>
 
@@ -80,6 +81,14 @@ bool Group::addChild( Node *child )
                 );
         }
 
+        if (child->getNumChildrenWithOccluderNodes()>0 ||
+            dynamic_cast<osg::OccluderNode*>(child))
+        {
+            setNumChildrenWithOccluderNodes(
+                getNumChildrenWithOccluderNodes()+1
+                );
+        }
+
         return true;
     }
     else return false;
@@ -114,6 +123,14 @@ bool Group::removeChild( Node *child )
                 );
         }
 
+        if (child->getNumChildrenWithOccluderNodes()>0 ||
+            dynamic_cast<osg::OccluderNode*>(child))
+        {
+            setNumChildrenWithOccluderNodes(
+                getNumChildrenWithOccluderNodes()-1
+                );
+        }
+
         // note ref_ptr<> automatically handles decrementing child's reference count.
         _children.erase(itr);
         dirtyBound();

src/osg/Makefile

@@ -12,6 +12,7 @@ CXXFILES =\
 	ClipPlane.cpp\
 	ColorMask.cpp\
 	ColorMatrix.cpp\
+	CollectOccludersVisitor.cpp\
 	ConvexPlanerPolygon.cpp\
 	ConvexPlanerOccluder.cpp\
 	CopyOp.cpp\

src/osg/Node.cpp

@@ -2,6 +2,7 @@
 #include <osg/Group>
 #include <osg/NodeVisitor>
 #include <osg/Notify>
+#include <osg/OccluderNode>
 
 #include <algorithm>
 
@@ -17,6 +18,7 @@ Node::Node()
     _cullingActive = true;
     _numChildrenWithCullingDisabled = 0;
 
+    _numChildrenWithOccluderNodes = 0;
 }
 
 Node::Node(const Node& node,const CopyOp& copyop):
@@ -30,6 +32,7 @@ Node::Node(const Node& node,const CopyOp& copyop):
         _cullCallback(node._cullCallback),
         _cullingActive(node._cullingActive),
         _numChildrenWithCullingDisabled(0), // assume no children yet.
+        _numChildrenWithOccluderNodes(0),
         _userData(copyop(node._userData.get())),
         _nodeMask(node._nodeMask), 
         _descriptions(node._descriptions),
@@ -227,6 +230,48 @@ void Node::setNumChildrenWithCullingDisabled(const int num)
 }
 
 
+void Node::setNumChildrenWithOccluderNodes(const int num)
+{
+    // if no changes just return.
+    if (_numChildrenWithOccluderNodes==num) return;
+
+    // note, if this node is a OccluderNode then the
+    // parents won't be affected by any changes to
+    // _numChildrenWithOccluderNodes so no need to inform them.
+    if (!dynamic_cast<OccluderNode*>(this) && !_parents.empty())
+    {
+    
+        // need to pass on changes to parents.        
+        int delta = 0;
+        if (_numChildrenWithOccluderNodes>0) --delta;
+        if (num>0) ++delta;
+        if (delta!=0)
+        {
+            // the number of callbacks has changed, need to pass this
+            // on to parents so they know whether app traversal is
+            // reqired on this subgraph.
+            for(ParentList::iterator itr =_parents.begin();
+                itr != _parents.end();
+                ++itr)
+            {    
+                (*itr)->setNumChildrenWithOccluderNodes(
+                    (*itr)->getNumChildrenWithOccluderNodes()+delta
+                    );
+            }
+
+        }
+    }
+    
+    // finally update this objects value.
+    _numChildrenWithOccluderNodes=num;
+    
+}
+
+const bool Node::containsOccluderNodes() const
+{
+    return _numChildrenWithOccluderNodes>0 || dynamic_cast<const OccluderNode*>(this);
+}
+
 const bool Node::computeBound() const
 {
     _bsphere.init();

src/osgUtil/SceneView.cpp

@@ -8,6 +8,7 @@
 #include <osg/TexEnv>
 #include <osg/ColorMatrix>
 #include <osg/LightModel>
+#include <osg/CollectOccludersVisitor>
 
 #include <osg/GLU>
 
@@ -306,6 +307,34 @@ void SceneView::cullStage(osg::Matrix* projection,osg::Matrix* modelview,osgUtil
     if (!_initCalled) init();
 
 
+    // collect any occluder in the view frustum.
+    if (_sceneData->containsOccluderNodes())
+    {
+        std::cout << "Scene graph contains occluder nodes, searching for them"<<std::endl;
+        osg::CollectOccludersVisitor cov;
+        
+        cov.setFrameStamp(_frameStamp.get());
+
+        // use the frame number for the traversal number.
+        if (_frameStamp.valid())
+        {
+             cov.setTraversalNumber(_frameStamp->getFrameNumber());
+        }
+
+        cov.pushViewport(_viewport.get());
+        cov.pushProjectionMatrix(projection);
+        cov.pushModelViewMatrix(modelview);
+
+        // traverse the scene graph to search for occluder in there new positions.
+        _sceneData->accept(cov);
+
+        cov.popModelViewMatrix();
+        cov.popProjectionMatrix();
+        cov.popViewport();
+
+        std::cout << "finished searching for occluder"<<std::endl;
+    }
+    
 
 
     cullVisitor->reset();