/*******************************************************************************
* Copyright (c) 2013, Daniel Murphy
* All rights reserved.
*
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* 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.
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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/*
* JBox2D - A Java Port of Erin Catto's Box2D
*
* JBox2D homepage: http://jbox2d.sourceforge.net/
* Box2D homepage: http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
package org.jbox2d.dynamics.joints;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
//Updated to rev 56->130->142 of b2DistanceJoint.cpp/.h
/**
* Distance joint definition. This requires defining an
* anchor point on both bodies and the non-zero length of the
* distance joint. The definition uses local anchor points
* so that the initial configuration can violate the constraint
* slightly. This helps when saving and loading a game.
* @warning Do not use a zero or short length.
*/
public class DistanceJointDef extends JointDef {
/** The local anchor point relative to body1's origin. */
public final Vec2 localAnchorA;
/** The local anchor point relative to body2's origin. */
public final Vec2 localAnchorB;
/** The equilibrium length between the anchor points. */
public float length;
/**
* The mass-spring-damper frequency in Hertz.
*/
public float frequencyHz;
/**
* The damping ratio. 0 = no damping, 1 = critical damping.
*/
public float dampingRatio;
public DistanceJointDef() {
type = JointType.DISTANCE;
localAnchorA = new Vec2(0.0f, 0.0f);
localAnchorB = new Vec2(0.0f, 0.0f);
length = 1.0f;
frequencyHz = 0.0f;
dampingRatio = 0.0f;
}
/**
* Initialize the bodies, anchors, and length using the world
* anchors.
* @param b1 First body
* @param b2 Second body
* @param anchor1 World anchor on first body
* @param anchor2 World anchor on second body
*/
public void initialize(final Body b1, final Body b2, final Vec2 anchor1, final Vec2 anchor2) {
bodyA = b1;
bodyB = b2;
localAnchorA.set(bodyA.getLocalPoint(anchor1));
localAnchorB.set(bodyB.getLocalPoint(anchor2));
Vec2 d = anchor2.sub(anchor1);
length = d.length();
}
}