com.badlogic.gdx.physics.box2d.joints.PrismaticJointDef Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.physics.box2d.joints;

import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.JointDef;

/** 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. */
public class PrismaticJointDef extends JointDef {
	public PrismaticJointDef () {
		type = JointType.PrismaticJoint;
	}

	/** Initialize the bodies, anchors, axis, and reference angle using the world anchor and world axis. */
	public void initialize (Body bodyA, Body bodyB, Vector2 anchor, Vector2 axis) {
		this.bodyA = bodyA;
		this.bodyB = bodyB;
		localAnchorA.set(bodyA.getLocalPoint(anchor));
		localAnchorB.set(bodyB.getLocalPoint(anchor));
		localAxisA.set(bodyA.getLocalVector(axis));
		referenceAngle = bodyB.getAngle() - bodyA.getAngle();

	}

	/** The local anchor point relative to body1's origin. */
	public final Vector2 localAnchorA = new Vector2();

	/** The local anchor point relative to body2's origin. */
	public final Vector2 localAnchorB = new Vector2();

	/** The local translation axis in body1. */
	public final Vector2 localAxisA = new Vector2(1, 0);

	/** The constrained angle between the bodies: body2_angle - body1_angle. */
	public float referenceAngle = 0;

	/** Enable/disable the joint limit. */
	public boolean enableLimit = false;

	/** The lower translation limit, usually in meters. */
	public float lowerTranslation = 0;

	/** The upper translation limit, usually in meters. */
	public float upperTranslation = 0;

	/** Enable/disable the joint motor. */
	public boolean enableMotor = false;

	/** The maximum motor torque, usually in N-m. */
	public float maxMotorForce = 0;

	/** The desired motor speed in radians per second. */
	public float motorSpeed = 0;

	@Override
	public org.jbox2d.dynamics.joints.JointDef toJBox2d () {
		org.jbox2d.dynamics.joints.PrismaticJointDef jd = new org.jbox2d.dynamics.joints.PrismaticJointDef();
		jd.bodyA = bodyA.body;
		jd.bodyB = bodyB.body;
		jd.collideConnected = collideConnected;
		jd.enableLimit = enableLimit;
		jd.enableMotor = enableMotor;
		jd.localAnchorA.set(localAnchorA.x, localAnchorA.y);
		jd.localAnchorB.set(localAnchorB.x, localAnchorB.y);
		jd.localAxisA.set(localAxisA.x, localAxisA.y);
		jd.lowerTranslation = lowerTranslation;
		jd.maxMotorForce = maxMotorForce;
		jd.motorSpeed = motorSpeed;
		jd.referenceAngle = referenceAngle;
		jd.type = org.jbox2d.dynamics.joints.JointType.PRISMATIC;
		jd.upperTranslation = upperTranslation;
		return jd;
	}
}