/*******************************************************************************
* 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,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* 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.
******************************************************************************/
package org.jbox2d.dynamics.joints;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
/**
* Prismatic 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.
*
* @warning at least one body should by dynamic with a non-fixed rotation.
* @author Daniel
*
*/
public class PrismaticJointDef 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 local translation axis in body1.
*/
public final Vec2 localAxisA;
/**
* The constrained angle between the bodies: body2_angle - body1_angle.
*/
public float referenceAngle;
/**
* Enable/disable the joint limit.
*/
public boolean enableLimit;
/**
* The lower translation limit, usually in meters.
*/
public float lowerTranslation;
/**
* The upper translation limit, usually in meters.
*/
public float upperTranslation;
/**
* Enable/disable the joint motor.
*/
public boolean enableMotor;
/**
* The maximum motor torque, usually in N-m.
*/
public float maxMotorForce;
/**
* The desired motor speed in radians per second.
*/
public float motorSpeed;
public PrismaticJointDef() {
super(JointType.PRISMATIC);
localAnchorA = new Vec2();
localAnchorB = new Vec2();
localAxisA = new Vec2(1.0f, 0.0f);
referenceAngle = 0.0f;
enableLimit = false;
lowerTranslation = 0.0f;
upperTranslation = 0.0f;
enableMotor = false;
maxMotorForce = 0.0f;
motorSpeed = 0.0f;
}
/**
* Initialize the bodies, anchors, axis, and reference angle using the world anchor and world
* axis.
*/
public void initialize(Body b1, Body b2, Vec2 anchor, Vec2 axis) {
bodyA = b1;
bodyB = b2;
bodyA.getLocalPointToOut(anchor, localAnchorA);
bodyB.getLocalPointToOut(anchor, localAnchorB);
bodyA.getLocalVectorToOut(axis, localAxisA);
referenceAngle = bodyB.getAngle() - bodyA.getAngle();
}
}