WheelJointDef.java

/*
 * The MIT License (MIT)
 *
 * FXGL - JavaFX Game Library
 *
 * Copyright (c) 2015-2017 AlmasB (almaslvl@gmail.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
/**
 * Created at 7:27:31 AM Jan 21, 2011
 */
package org.jbox2d.dynamics.joints;

import com.almasb.fxgl.core.math.Vec2;
import org.jbox2d.dynamics.Body;

/**
 * Wheel 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.
 *
 * @author Daniel Murphy
 */
public class WheelJointDef extends JointDef {

    /**
     * The local anchor point relative to body1's origin.
     */
    public final Vec2 localAnchorA = new Vec2();

    /**
     * The local anchor point relative to body2's origin.
     */
    public final Vec2 localAnchorB = new Vec2();

    /**
     * The local translation axis in body1.
     */
    public final Vec2 localAxisA = new Vec2();

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

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

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

    /**
     * Suspension frequency, zero indicates no suspension
     */
    public float frequencyHz;

    /**
     * Suspension damping ratio, one indicates critical damping
     */
    public float dampingRatio;

    public WheelJointDef() {
        super(JointType.WHEEL);
        localAxisA.set(1, 0);
        enableMotor = false;
        maxMotorTorque = 0f;
        motorSpeed = 0f;
    }

    public void initialize(Body b1, Body b2, Vec2 anchor, Vec2 axis) {
        bodyA = b1;
        bodyB = b2;
        b1.getLocalPointToOut(anchor, localAnchorA);
        b2.getLocalPointToOut(anchor, localAnchorB);
        bodyA.getLocalVectorToOut(axis, localAxisA);
    }
}