From Michael Gronager, osgSim::VisibilityGroup

src/osgSim/GNUmakefile

@@ -15,6 +15,8 @@ CXXFILES = \
     SphereSegment.cpp\
     MultiSwitch.cpp\
     Version.cpp\
+    VisibilityGroup.cpp\
+
 
 DEF     += -DOSGSIM_LIBRARY
 

src/osgSim/VisibilityGroup.cpp

@@ -0,0 +1,84 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 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 <osgSim/VisibilityGroup>
+
+#include <osgUtil/CullVisitor>
+#include <osgUtil/IntersectVisitor>
+
+using namespace osgSim;
+
+VisibilityGroup::VisibilityGroup():
+    _volumeIntersectionMask(0xFFFFFFFF),
+    _segmentLength(0.f)
+{
+}
+
+VisibilityGroup::VisibilityGroup(const VisibilityGroup& sw,const osg::CopyOp& copyop):
+    osg::Group(sw,copyop),
+    _volumeIntersectionMask(0xFFFFFFFF),
+    _segmentLength(0.f)
+{
+}
+
+void VisibilityGroup::traverse(osg::NodeVisitor& nv)
+{
+    if (nv.getTraversalMode()==osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN && nv.getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
+    {
+        // cast to cullvisitor
+        osgUtil::CullVisitor& cv = (osgUtil::CullVisitor&) nv;
+
+        // here we test if we are inside the visibilityvolume
+
+        // first get the eyepoint and in local coordinates
+        osg::Vec3 eye = cv.getEyeLocal();
+        osg::Vec3 look = cv.getLookVectorLocal();
+
+        // now scale the segment to the segment length - if 0 use the group bounding sphere radius
+        float length = _segmentLength;
+        if(length == 0.f)
+            length = getBound().radius();
+        look *= length;
+        osg::Vec3 center = eye + look;
+
+        osg::Vec3 seg = center - eye;
+
+        // perform the intersection using the given mask
+        osgUtil::IntersectVisitor iv;
+        osg::ref_ptr<osg::LineSegment> lineseg = new osg::LineSegment;
+        lineseg->set(eye, center);
+        iv.addLineSegment(lineseg.get());
+        iv.setTraversalMask(_volumeIntersectionMask);
+
+        if(_visibilityVolume.valid())
+            _visibilityVolume->accept(iv);
+
+        // now examine the hit record
+        if(iv.hits())
+        {
+            osgUtil::IntersectVisitor::HitList& hitList = iv.getHitList(lineseg.get());
+            if(!hitList.empty()) // we actually hit something
+            {
+                //                notify(INFO) << "Hit obstruction"<< std::endl;
+                osg::Vec3 normal = hitList.front().getLocalIntersectNormal();
+                if((normal*seg) > 0.f ) // we are inside
+                    Group::traverse(nv);
+            }
+        }
+    }
+    else
+    {
+        Group::traverse(nv);
+    }
+}
+