OsgCalculateBoundingBox.h

#include <osg/NodeVisitor>
#include <osg/BoundingBox>
#include <osg/BoundingSphere>
#include <osg/MatrixTransform>
#include <osg/Billboard>
 
namespace OsgAnimatSim
{

        class ANIMAT_OSG_PORT OsgCalculateBoundingBox : public osg::NodeVisitor {
 
        public:
 
                 OsgCalculateBoundingBox() : NodeVisitor( NodeVisitor::TRAVERSE_ALL_CHILDREN ) {
                 // ----------------------------------------------------------------------
                 //
                 //     Default Public Class Constructor
                 //
                 // ----------------------------------------------------------------------
                                      
                                m_transformMatrix.makeIdentity();
     
                                }
            
     
       
                virtual ~OsgCalculateBoundingBox() {}
 
 
                virtual
                void apply( osg::Geode &geode ) {
                // -------------------------------------------
                //
                //   Handle nodes of the type osg::Geode
                //
                // -------------------------------------------
    
                        if(geode.getNumDrawables() > 0) {
                                osg::BoundingBox bbox;
        
                                //
                                // update bounding box for each drawable
                                //
                                for(  unsigned int i = 0; i < geode.getNumDrawables(); ++i ){
            
                                        //
                                        // expand the overall bounding box
                                        //
 
                                        bbox.expandBy( geode.getDrawable( i )->getBound());
                                        }
 
                                //
                                // transform corners by current matrix
                                //
                                osg::BoundingBox bboxTrans;
        
                                for( unsigned int i = 0; i < 8; ++i ) {
        
                                        osg::Vec3 xvec = bbox.corner( i ) * m_transformMatrix;
        
                                        bboxTrans.expandBy( xvec );
 
                                        }
 
                                //
                                // update the overall bounding box size
                                //
                                m_boundingBox.expandBy( bboxTrans );
 
                                //
                                // continue traversing through the graph
                                //
                                traverse( geode );
                        }               
                } // ::apply(osg::Geode &geode)
        
 
                virtual
                void apply( osg::MatrixTransform &node ) {
                // ---------------------------------------------------------
                //
                //   Handle nodes of the type osg::MatrixTransform
                //
                // ---------------------------------------------------------
 
                        m_transformMatrix *= node.getMatrix();
 
                        //
                        // continue traversing through the graph
                        //
                        traverse( node );
 
                        } // ::apply(osg::MatrixTransform &node)
        
         
                virtual
                void apply( osg::Billboard &node ){
                // -----------------------------------------------
                //
                //    Handle nodes of the type osg::Billboard
                //
                // -----------------------------------------------
    
                        //
                        // important to handle billboard so that its size will
                        // not affect the geode size continue traversing the graph
                        //
                        traverse( node );
 
                } // ::apply(osg::MatrixTransform &node)
    
    
                //
                // return teh bounding box     
                //
                osg::BoundingBox &getBoundBox() { return m_boundingBox; }  
 
        protected :
 
                osg::BoundingBox m_boundingBox;          // the overall resultant bounding box
                osg::Matrix      m_transformMatrix;      // the current transform matrix
 
 
        };  // class  OsgCalculateBoundingBox

}// end OsgAnimatSim