com.almasb.fxgl.physics.box2d.dynamics.joints.MotorJointDef Maven / Gradle / Ivy

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/*
 * FXGL - JavaFX Game Library. The MIT License (MIT).
 * Copyright (c) AlmasB ([email protected]).
 * See LICENSE for details.
 */

package com.almasb.fxgl.physics.box2d.dynamics.joints;

import com.almasb.fxgl.core.math.Vec2;
import com.almasb.fxgl.physics.box2d.dynamics.Body;

/**
 * Motor joint definition.
 *
 * @author dmurph
 */
public class MotorJointDef extends JointDef {
    /**
     * Position of bodyB minus the position of bodyA, in bodyA's frame, in meters.
     */
    public final Vec2 linearOffset = new Vec2();

    /**
     * The bodyB angle minus bodyA angle in radians.
     */
    public float angularOffset;

    /**
     * The maximum motor force in N.
     */
    public float maxForce;

    /**
     * The maximum motor torque in N-m.
     */
    public float maxTorque;

    /**
     * Position correction factor in the range [0,1].
     */
    public float correctionFactor;

    public MotorJointDef() {
        super(JointType.MOTOR);
        angularOffset = 0;
        maxForce = 1;
        maxTorque = 1;
        correctionFactor = 0.3f;
    }

    public void initialize(Body bA, Body bB) {
        bodyA = bA;
        bodyB = bB;
        Vec2 xB = bodyB.getPosition();
        bodyA.getLocalPointToOut(xB, linearOffset);

        float angleA = bodyA.getAngle();
        float angleB = bodyB.getAngle();
        angularOffset = angleB - angleA;
    }
}