springpointforce.java

java 3d game jme 工程开发源代码

/*
 * Copyright (c) 2003-2009 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
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 *
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 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
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 *   documentation and/or other materials provided with the distribution.
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 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 */

package com.jme.math.spring;

import java.io.IOException;

import com.jme.util.export.InputCapsule;
import com.jme.util.export.JMEExporter;
import com.jme.util.export.JMEImporter;
import com.jme.util.export.OutputCapsule;
import com.jme.util.export.Savable;

/**
 * <code>SpringPointForce</code> is an abstract class defining an external
 * force to be used with the SpringSystem class.
 *
 * @author Joshua Slack
 * @version $Id: SpringPointForce.java,v 1.4 2006/06/01 15:05:46 nca Exp $
 */
public abstract class SpringPointForce implements Savable {

	/**
	 * Is this force enabled?  ie, should it be used when calculating forces
	 * in a system it is added to.
	 */
	private boolean enabled = true;

	/**
	 * Set this force enabled or not.
	 * @param enabled boolean
	 */
	public void setEnabled(boolean enabled) {
		this.enabled = enabled;
	}

	/**
	 * Return whether or not this system is enabled.
	 * @return boolean
	 */
	public boolean isEnabled() {
		return enabled;
	}

	/**
	 * Apply the force defined by this class on a given point.
	 * Should do this by making a call to
	 * <i>node.acceleration.addLocal(....);</i>
	 * @param dt amount of time since last apply call in ms.
	 * @param node the node to apply the force to.
	 */
	public abstract void apply(float dt, SpringPoint node);
    
    public void write(JMEExporter e) throws IOException {
        OutputCapsule capsule = e.getCapsule(this);
        capsule.write(enabled, "enabled", true);
    }
    
    public void read(JMEImporter e) throws IOException {
        InputCapsule capsule = e.getCapsule(this);
        enabled = capsule.readBoolean("enabled", true);
    }
    
    public Class getClassTag() {
        return this.getClass();
    }
}