PrismaticJointDef.java

/*
 * 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 of b2PrismaticJoint.cpp/.h
/**
 * A prismatic joint definition. This joint provides one degree of freedom: translation
 * along an axis fixed in body1. Relative rotation is prevented. You can
 * use a joint limit to restrict the range of motion and a joint motor to
 * drive the motion or to model joint friction.
 */
public class PrismaticJointDef extends JointDef {
	public PrismaticJointDef() {
		type = JointType.PRISMATIC_JOINT;
		localAnchor1 = new Vec2();
		localAnchor2 = new Vec2();
		localAxis1 = new Vec2();
		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(final Body b1, final Body b2, final Vec2 anchor, final Vec2 axis) {
		body1 = b1;
		body2 = b2;
		body1.getLocalPointToOut(anchor, localAnchor1);
		body2.getLocalPointToOut(anchor, localAnchor2);
		body1.getLocalVectorToOut(axis, localAxis1);
		referenceAngle = body2.getAngle() - body1.getAngle();
	}

	/// The local anchor point relative to body1's origin.
	public Vec2 localAnchor1;

	/// The local anchor point relative to body2's origin.
	public Vec2 localAnchor2;

	/// The local translation axis in body1.
	public 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;
}