org.jbox2d.dynamics.joints.PrismaticJointDef Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of playn-jbox2d Show documentation
A GWT-compatible port of JBox2D, for use with PlayN games.
There is a newer version: 1.9.1
/*******************************************************************************
 * Copyright (c) 2011, 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.
 *     * Neither the name of the  nor the
 *       names of its contributors 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 DANIEL MURPHY 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 localAxis1;

	/**
	 * 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(){
		type = JointType.PRISMATIC;
		localAnchorA = new Vec2();
		localAnchorB = new Vec2();
		localAxis1 = 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, localAxis1);
		referenceAngle = bodyB.getAngle() - bodyA.getAngle();
	}
}