boundsbehavior.java

《Java 3D编程》的源代码

/**********************************************************
  Copyright (C) 2001 	Daniel Selman

  First distributed with the book "Java 3D Programming"
  by Daniel Selman and published by Manning Publications.
  http://manning.com/selman

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation, version 2.

  This program 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
  GNU General Public License for more details.

  The license can be found on the WWW at:
  http://www.fsf.org/copyleft/gpl.html

  Or by writing to:
  Free Software Foundation, Inc.,
  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

  Authors can be contacted at:
  Daniel Selman: [e-mail]

  If you make changes you think others would like, please 
  contact one of the authors or someone at the 
  www.j3d.org web site.
**************************************************************/

package org.selman.java3d.book.common;

import javax.media.j3d.*;
import javax.vecmath.*;

import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.*;

// this class implements a simple behavior that
// displays a graphical representation of the Bounds
// of a Node.

public class BoundsBehavior extends Behavior
{
	// the wake up condition for the behavior
	protected WakeupCondition	m_WakeupCondition = null;

	// the Node that we are tracking
	protected Node					m_Node = null;
	protected TransformGroup	m_TransformGroup = null;
	protected Switch				m_BoundsSwitch = null;

	protected Transform3D		m_Transform3D = null;
	protected Vector3d 			m_Scale = null;
	protected Vector3d 			m_Vector3d = null;
	protected Point3d 			m_Point3d1 = null;
	protected Point3d 			m_Point3d2 = null;

	private final int				m_kSphereBounds = 0;
	private final int				m_kBoxBounds = 1;

	public BoundsBehavior( Node node )
	{
		// save the GeometryArray that we are modifying
		m_Node = node;

		m_Transform3D = new Transform3D( );
		m_Scale = new Vector3d( );
		m_Vector3d = new Vector3d( );
		m_Point3d1 = new Point3d( );
		m_Point3d2 = new Point3d( );

		// set the capability bits that the behavior requires
		m_Node.setCapability( Node.ALLOW_BOUNDS_READ );

		// save the WakeupCriterion for the behavior
		m_WakeupCondition = new WakeupOnElapsedFrames( 10 );
	}

	public void addBehaviorToParentGroup( Group nodeParentGroup )
	{
		nodeParentGroup.addChild( this );

		m_TransformGroup = new TransformGroup( );
		m_TransformGroup.setCapability( TransformGroup.ALLOW_TRANSFORM_WRITE );

		m_BoundsSwitch = new Switch( );
		m_BoundsSwitch.setCapability( Switch.ALLOW_SWITCH_WRITE );

		Appearance app = new Appearance( );

		PolygonAttributes polyAttrbutes = new PolygonAttributes( );
		polyAttrbutes.setPolygonMode( PolygonAttributes.POLYGON_LINE );
		polyAttrbutes.setCullFace( PolygonAttributes.CULL_NONE ) ;
		app.setPolygonAttributes( polyAttrbutes );

		m_BoundsSwitch.addChild( new Sphere( 1, app ) );

		ColorCube cube = new ColorCube( );
		cube.setAppearance( app );

		Group g = new Group( );
		g.addChild( cube );
		m_BoundsSwitch.addChild( g );

		m_BoundsSwitch.setWhichChild( Switch.CHILD_NONE );

		m_TransformGroup.addChild( m_BoundsSwitch );
		nodeParentGroup.addChild( m_TransformGroup );
	}

	public void setEnable( boolean bEnable )
	{
		super.setEnable( bEnable );

		if( m_BoundsSwitch != null )
		{
			if( bEnable == false )
				m_BoundsSwitch.setWhichChild( Switch.CHILD_NONE );
		}
	}

	public void initialize( )
	{
		// apply the initial WakeupCriterion
		wakeupOn( m_WakeupCondition );
	}

	public void processStimulus( java.util.Enumeration criteria )
	{				
		while( criteria.hasMoreElements( ) )
		{
			WakeupCriterion wakeUp = (WakeupCriterion) criteria.nextElement( );			

			// every N frames, update position of the graphic
			if( wakeUp instanceof WakeupOnElapsedFrames )
			{
				if( m_TransformGroup != null )
				{
					Bounds bounds = m_Node.getBounds( );

					int nBoundsType = m_kBoxBounds;
					m_Transform3D.setIdentity( );

					if( bounds instanceof BoundingSphere )
					{
						nBoundsType = m_kSphereBounds;

						((BoundingSphere) bounds).getCenter( m_Point3d1 );

						m_Vector3d.x = m_Point3d1.x;
						m_Vector3d.y = m_Point3d1.y;
						m_Vector3d.z = m_Point3d1.z;

						m_Scale.x = ((BoundingSphere) bounds).getRadius( ) / 2;
						m_Scale.y = m_Scale.x;
						m_Scale.z = m_Scale.y;

					}
					else if( bounds instanceof BoundingBox )
					{
						nBoundsType = m_kBoxBounds;

						((BoundingBox) bounds).getLower( m_Point3d1 );
						((BoundingBox) bounds ).getUpper( m_Point3d2 );

						m_Vector3d.x = (m_Point3d1.x + m_Point3d2.x) / 2;
						m_Vector3d.y = (m_Point3d1.y + m_Point3d2.y) / 2;
						m_Vector3d.z = (m_Point3d1.z + m_Point3d2.z) / 2;

						m_Scale.x = Math.abs( m_Point3d1.x - m_Point3d2.x ) / 2;
						m_Scale.y = Math.abs( m_Point3d1.y - m_Point3d2.y ) / 2;
						m_Scale.z = Math.abs( m_Point3d1.z - m_Point3d2.z ) / 2;
					}
					else
						System.err.println( "BoundsBehavior found a Bounds it cannot represent: " + bounds );

					m_Transform3D.setScale( m_Scale );
					m_Transform3D.setTranslation( m_Vector3d );

					m_TransformGroup.setTransform( m_Transform3D );

					m_BoundsSwitch.setWhichChild( nBoundsType );
				}
				else
				{
					System.err.println( "Call addBehaviorToParentGroup for BoundsBehavior." );
				}
			}
		}

		// assign the next WakeUpCondition, so we are notified again
		wakeupOn( m_WakeupCondition );
	}
}