viewingplatform.java

JAVA3D矩陈的相关类

/*
 * $RCSfile: ViewingPlatform.java,v $
 *
 * Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that this software is not designed, licensed or
 * intended for use in the design, construction, operation or
 * maintenance of any nuclear facility.
 *
 * $Revision: 1.4 $
 * $Date: 2007/02/09 17:20:45 $
 * $State: Exp $
 */

package com.sun.j3d.utils.universe;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import java.awt.Component;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.vp.*;
import com.sun.j3d.internal.J3dUtilsI18N;

/**
 * This class is used to set up the "view" side of a Java 3D scene graph.
 * The ViewingPlatform object contains a MultiTransformGroup node to allow
 * for a series of transforms to be linked together.  To this structure
 * the ViewPlatform is added as well as any geometry to associate with this
 * view platform.
 *
 * @see ViewPlatform
 */
public class ViewingPlatform extends BranchGroup {

    /**
     * Cached ViewPlatform associated with this ViewingPlatform object.
     */
    protected ViewPlatform        viewPlatform;

    /**
     * MultiTransformGroup that holds all TransformGroups between
     * the BranchGroup and the View object.
     */
    protected MultiTransformGroup mtg;

    /**
     * Used to keep track of added geometry.  When geometry
     * is added to the view platform, an addChild to this BranchGroup
     * is performed.
     */
    protected BranchGroup         platformGeometryRoot;

    /**
     * Used to keep track of added geometry.  When geometry
     * is added for an avatar, an addChild to this BranchGroup
     * is performed.
     */
    protected BranchGroup         avatarRoot;

    /**
     * Cached PlatformGeometry object.
     */
    protected PlatformGeometry    platformGeometry = null;

    /**
     * Table of the Viewer objects.
     */
    protected Hashtable		viewerList;

    /**
     * Used to keep track of behaviors.
     *
     * @since Java 3D 1.2.1
     */
    protected BranchGroup behaviors;

    /** 
     * The universe to which this viewing platform is attached
     *
     * @since Java 3D 1.3
     */
    protected SimpleUniverse universe;
    
    /**
     * Creates a default ViewingPlatform object.  This consists of a
     * MultiTransfromGroup node with one transform and a ViewPlatform
     * object. The ViewPlatform is positioned at (0.0, 0.0, 0.0).
     */
    public ViewingPlatform() {
        // Call main constructor with default values.
        this(1);
    }

    /**
     * Creates the ViewingPlatform object.  This consists of a
     * MultiTransfromGroup node with the specified number of transforms
     * (all initialized to the identity transform).
     * and a ViewPlatform object.
     *
     * @param numTransforms The number of transforms the MultiTransformGroup
     *  node should contain.  If this number is less than 1, 1 is assumed.
     */
    public ViewingPlatform(int numTransforms) {
        viewerList = new Hashtable();

        // Set default capabilities for this node.
        setCapability(Group.ALLOW_CHILDREN_WRITE);
        setCapability(Group.ALLOW_CHILDREN_EXTEND);
        setCapability(BranchGroup.ALLOW_DETACH);

        // Create MultiTransformGroup node.
        if (numTransforms < 1)
            numTransforms = 1;
        mtg = new MultiTransformGroup(numTransforms);

        // Get first transform and add it to the scene graph.
        TransformGroup tg = mtg.getTransformGroup(0);
        addChild(tg);

        // Create ViewPlatform and add it to the last transform in the
        // MultiTransformGroup node.
        tg = mtg.getTransformGroup(numTransforms - 1);
        viewPlatform = new ViewPlatform();
        viewPlatform.setCapability(ViewPlatform.ALLOW_POLICY_READ);
        viewPlatform.setCapability(ViewPlatform.ALLOW_POLICY_WRITE);
        tg.addChild(viewPlatform);

        // Set capabilities to allow for changes when live.
        tg.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
        tg.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);

        // Initialize the avatarRoot BranchGroup node and add it to the
        // last transform in the MultiTransformGroup node.
        avatarRoot = new BranchGroup();
        avatarRoot.setCapability(Group.ALLOW_CHILDREN_READ);
        avatarRoot.setCapability(Group.ALLOW_CHILDREN_WRITE);
        avatarRoot.setCapability(Group.ALLOW_CHILDREN_EXTEND);
        tg.addChild(avatarRoot);

        // Initialize the platformGeometry BranchGroup node and add it to the
        // last transform in the MultiTransformGroup node.
        platformGeometryRoot = new BranchGroup();
        platformGeometryRoot.setCapability(Group.ALLOW_CHILDREN_READ);
        platformGeometryRoot.setCapability(Group.ALLOW_CHILDREN_WRITE);
        platformGeometryRoot.setCapability(Group.ALLOW_CHILDREN_EXTEND);
        tg.addChild(platformGeometryRoot);
    }

    /**
     * Sets the ViewPlatform node for this ViewingPlatform object.
     *
     * @param vp The ViewPlatform node to associate with this ViewingPlatform
     *  object.
     */
    public void setViewPlatform(ViewPlatform vp) {
	TransformGroup tg = getViewPlatformTransform();
	tg.removeChild(viewPlatform);
	tg.addChild(vp);
        viewPlatform = vp;
        // Assign this to all Viewers.
        Enumeration e = viewerList.keys();

        while (e.hasMoreElements())
            ((Viewer)e.nextElement()).setViewingPlatform(this);
    }

    /**
     * Returns the ViewPlatform node for this ViewingPlatform object.
     *
     * @return The ViewPlatform node associated with this ViewingPlatform
     *  object.
     */
    public ViewPlatform getViewPlatform() {
        return viewPlatform;
    }

    /**
     * Assigns the geometry to associate with the ViewingPlatform.
     * PlatformGeometry is used to hold any geometry to be associated
     * with the ViewingPlatform.  If the ViewingPlatform is to be the
     * inside of a car, for instance, than the PlatformGeometry could be
     * the dashboard of the car.
     * 
     * @param pg The geometry to be associated with this ViewingPlatform.
     *  Passing in null has the effect of deleting any geometry associated
     *  with this ViewingPlatform.
     */
    public void setPlatformGeometry(PlatformGeometry pg) {
        // Just return if trying to set the same PlatformGeometry object.
        if (platformGeometry == pg)
            return;

        // If the PlatformGeometry is null, will be removing any geometry
        // already present.
        if (pg == null) {
            if (platformGeometryRoot.numChildren() != 0)
                platformGeometryRoot.removeChild(0);
        }
        else {

            // See if there is an old PlatformGeometry to replace.
            if (platformGeometryRoot.numChildren() != 0)
                platformGeometryRoot.setChild(pg, 0);
            else {
                platformGeometryRoot.addChild(pg);
            }
        }
        platformGeometry = pg;
    }

    /**
      * Returns the PlatformGeometry associated with this ViewingPlatform
      *
      * @return The PlatformGeometry associated with this ViewingPlatform
      */
    public PlatformGeometry getPlatformGeometry() {
	return platformGeometry;
    }

    /**
     * Returns the MultitransformGroup object for this
     * ViewingPlatform object.
     *
     * @return The MultitransformGroup object.
     */
    public MultiTransformGroup getMultiTransformGroup() {
        return mtg;
    }