/*******************************************************************************
 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 	* Redistributions of source code must retain the above copyright notice,
 * 	  this list of conditions and the following disclaimer.
 * 	* Redistributions 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.
 * 
 * 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 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 ******************************************************************************/
/**
 * Created at 7:27:31 AM Jan 21, 2011
 */
package org.jbox2d.dynamics.joints;

import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;

/**
 * Wheel joint definition. This requires defining a line of motion using an axis and an anchor
 * point. The definition uses local anchor points and a local axis so that the initial configuration
 * can violate the constraint slightly. The joint translation is zero when the local anchor points
 * coincide in world space. Using local anchors and a local axis helps when saving and loading a
 * game.
 * 
 * @author Daniel Murphy
 */
public class WheelJointDef extends JointDef {
	
	/**
	 * The local anchor point relative to body1's origin.
	 */
	public final Vec2 localAnchorA = new Vec2();
	
	/**
	 * The local anchor point relative to body2's origin.
	 */
	public final Vec2 localAnchorB = new Vec2();
	
	/**
	 * The local translation axis in body1.
	 */
	public final Vec2 localAxisA = new Vec2();

	/**
	 * Enable/disable the joint motor.
	 */
	public boolean enableMotor;
	
	/**
	 * The maximum motor torque, usually in N-m.
	 */
	public float maxMotorTorque;
	
	/**
	 * The desired motor speed in radians per second.
	 */
	public float motorSpeed;
	
	/**
	 * Suspension frequency, zero indicates no suspension
	 */
	public float frequencyHz;
	
	/**
	 * Suspension damping ratio, one indicates critical damping
	 */
	public float dampingRatio;
	
	public WheelJointDef() {
		type = JointType.WHEEL;
		localAxisA.set(1, 0);
		enableMotor = false;
		maxMotorTorque = 0f;
		motorSpeed = 0f;
	}
	
	public void initialize(Body b1, Body b2, Vec2 anchor, Vec2 axis) {
		bodyA = b1;
		bodyB = b2;
		b1.getLocalPointToOut(anchor, localAnchorA);
		b2.getLocalPointToOut(anchor, localAnchorB);
		bodyA.getLocalVectorToOut(axis, localAxisA);
	}
}
