/*******************************************************************************
* 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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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
******************************************************************************/
/*
* 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;
/**
* Revolute joint definition. This requires defining an anchor point where the bodies are joined.
* The definition uses local anchor points so that the initial configuration can violate the
* constraint slightly. You also need to specify the initial relative angle for joint limits. This
* helps when saving and loading a game. The local anchor points are measured from the body's origin
* rather than the center of mass because:<br/>
* <ul>
* <li>you might not know where the center of mass will be.</li>
* <li>if you add/remove shapes from a body and recompute the mass, the joints will be broken.</li>
* </ul>
*/
public class RevoluteJointDef extends JointDef {
/**
* The local anchor point relative to body1's origin.
*/
public Vec2 localAnchorA;
/**
* The local anchor point relative to body2's origin.
*/
public Vec2 localAnchorB;
/**
* The body2 angle minus body1 angle in the reference state (radians).
*/
public float referenceAngle;
/**
* A flag to enable joint limits.
*/
public boolean enableLimit;
/**
* The lower angle for the joint limit (radians).
*/
public float lowerAngle;
/**
* The upper angle for the joint limit (radians).
*/
public float upperAngle;
/**
* A flag to enable the joint motor.
*/
public boolean enableMotor;
/**
* The desired motor speed. Usually in radians per second.
*/
public float motorSpeed;
/**
* The maximum motor torque used to achieve the desired motor speed. Usually in N-m.
*/
public float maxMotorTorque;
public RevoluteJointDef() {
super(JointType.REVOLUTE);
localAnchorA = new Vec2(0.0f, 0.0f);
localAnchorB = new Vec2(0.0f, 0.0f);
referenceAngle = 0.0f;
lowerAngle = 0.0f;
upperAngle = 0.0f;
maxMotorTorque = 0.0f;
motorSpeed = 0.0f;
enableLimit = false;
enableMotor = false;
}
/**
* Initialize the bodies, anchors, and reference angle using the world anchor.
*
* @param b1
* @param b2
* @param anchor
*/
public void initialize(final Body b1, final Body b2, final Vec2 anchor) {
bodyA = b1;
bodyB = b2;
bodyA.getLocalPointToOut(anchor, localAnchorA);
bodyB.getLocalPointToOut(anchor, localAnchorB);
referenceAngle = bodyB.getAngle() - bodyA.getAngle();
}
}