From f9fb99dc437b1b156a8de08812671491e0e2d2c0 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 2 Nov 2006 12:17:06 +0000
Subject: [PATCH] Added prelimnary work on PolytopeIntersector.

---
 include/osgUtil/IntersectionVisitor | 57 ++++++++++++++++++
 src/osgUtil/IntersectionVisitor.cpp | 92 ++++++++++++++++++++++++++++-
 2 files changed, 146 insertions(+), 3 deletions(-)

diff --git a/include/osgUtil/IntersectionVisitor b/include/osgUtil/IntersectionVisitor
index 93cbc8da5..4d53d96cf 100644
--- a/include/osgUtil/IntersectionVisitor
+++ b/include/osgUtil/IntersectionVisitor
@@ -142,6 +142,63 @@ class OSGUTIL_EXPORT LineSegmentIntersector : public Intersector
     
 };
 
+/** Concrent class for implementing polytope intersections with the scene graph.
+  * To be used in conjunction with IntersectionVisitor. */
+class OSGUTIL_EXPORT PolytopeIntersector : public Intersector
+{
+    public:
+    
+        PolytopeIntersector(const osg::Polytope& polytope, PolytopeIntersector* parent=0);
+        
+        PolytopeIntersector(CoordinateFrame cf, const osg::Polytope& polytope, PolytopeIntersector* parent=0);
+        
+        struct Intersection
+        {
+            Intersection() {}
+        
+            bool operator < (const Intersection& rhs) const
+            {
+                if (nodePath < rhs.nodePath) return true;
+                if (rhs.nodePath < nodePath ) return false;
+                return (drawable < rhs.drawable);
+            }
+
+            osg::NodePath                   nodePath;
+            osg::ref_ptr<osg::Drawable>     drawable;
+        };
+        
+        typedef std::set<Intersection> Intersections;
+        
+        inline void insertIntersection(const Intersection& intersection) { getIntersections().insert(intersection); }
+
+        inline Intersections& getIntersections() { return _parent ? _parent->_intersections : _intersections; }
+
+        inline Intersection getFirstIntersection() { Intersections& intersections = getIntersections(); return intersections.empty() ? Intersection() : *(intersections.begin()); }
+
+    public:
+
+        virtual Intersector* clone(osgUtil::IntersectionVisitor& iv);
+        
+        virtual bool enter(const osg::Node& node);
+        
+        virtual void leave();
+        
+        virtual void intersect(osgUtil::IntersectionVisitor& iv, osg::Drawable* drawable);
+        
+        virtual void reset();
+
+        virtual bool containsIntersections() { return !_intersections.empty(); }
+
+    protected:
+
+        PolytopeIntersector* _parent;
+
+        osg::Polytope _polytope;
+        
+        Intersections _intersections;
+    
+};
+
 /** Concrent class for passing multiple intersectors through the scene graph.
   * To be used in conjunction with IntersectionVisitor. */
 class OSGUTIL_EXPORT IntersectorGroup : public Intersector
diff --git a/src/osgUtil/IntersectionVisitor.cpp b/src/osgUtil/IntersectionVisitor.cpp
index 8382c103f..5dad22f81 100644
--- a/src/osgUtil/IntersectionVisitor.cpp
+++ b/src/osgUtil/IntersectionVisitor.cpp
@@ -495,9 +495,94 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 //
-//  LineSegmentIntersector
+//  IntersectorGroup
 //
+PolytopeIntersector::PolytopeIntersector(const osg::Polytope& polytope, PolytopeIntersector* parent):
+    _parent(parent),
+    _polytope(polytope)
+{
+}
 
+PolytopeIntersector::PolytopeIntersector(CoordinateFrame cf, const osg::Polytope& polytope, PolytopeIntersector* parent):
+    Intersector(cf),
+    _parent(parent),
+    _polytope(polytope)
+{
+}
+
+Intersector* PolytopeIntersector::clone(osgUtil::IntersectionVisitor& iv)
+{
+    if (_coordinateFrame==MODEL && iv.getModelMatrix()==0)
+    {
+        return new PolytopeIntersector(_polytope, this);
+    }
+
+    // compute the matrix that takes this Intersector from its CoordinateFrame into the local MODEL coordinate frame
+    // that geometry in the scene graph will always be in.
+    osg::Matrix matrix;
+    switch (_coordinateFrame)
+    {
+        case(WINDOW): 
+            if (iv.getWindowMatrix()) matrix.preMult( *iv.getWindowMatrix() );
+            if (iv.getProjectionMatrix()) matrix.preMult( *iv.getProjectionMatrix() );
+            if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
+            if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
+            break;
+        case(PROJECTION): 
+            if (iv.getProjectionMatrix()) matrix.preMult( *iv.getProjectionMatrix() );
+            if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
+            if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
+            break;
+        case(VIEW): 
+            if (iv.getViewMatrix()) matrix.preMult( *iv.getViewMatrix() );
+            if (iv.getModelMatrix()) matrix.preMult( *iv.getModelMatrix() );
+            break;
+        case(MODEL):
+            if (iv.getModelMatrix()) matrix = *iv.getModelMatrix();
+            break;
+    }
+
+    osg::Polytope transformedPolytope;
+    transformedPolytope.setAndTransformProvidingInverse(_polytope, matrix);
+
+    return new PolytopeIntersector(transformedPolytope, this);
+}
+
+bool PolytopeIntersector::enter(const osg::Node& node)
+{
+    return !node.isCullingActive() || _polytope.contains( node.getBound() );
+}
+
+
+void PolytopeIntersector::leave()
+{
+    // do nothing.
+}
+
+
+void PolytopeIntersector::intersect(osgUtil::IntersectionVisitor& iv, osg::Drawable* drawable)
+{
+    if ( !_polytope.contains( drawable->getBound() ) ) return;
+
+    Intersection hit;
+    hit.nodePath = iv.getNodePath();
+    hit.drawable = drawable;
+}
+
+
+void PolytopeIntersector::reset()
+{
+    Intersector::reset();
+    
+    _intersections.clear();
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+//  IntersectorGroup
+//
 
 IntersectorGroup::IntersectorGroup()
 {
@@ -782,9 +867,10 @@ void IntersectionVisitor::apply(osg::Projection& projection)
 
 void IntersectionVisitor::apply(osg::CameraNode& camera)
 {
-    //osg::notify(osg::NOTICE)<<"apply(CameraNode&)"<<std::endl;
+    // osg::notify(osg::NOTICE)<<"apply(CameraNode&)"<<std::endl;
 
-    if (!enter(camera)) return;
+    // note, commenting out right now because default CameraNode setup is with the culling active.  Should this be changed?
+    // if (!enter(camera)) return;
     
     // osg::notify(osg::NOTICE)<<"inside apply(CameraNode&)"<<std::endl;