Creating a Hover Car with Physic

参考官方：https://unity3d.com/cn/learn/tutorials/modules/beginner/live-training-archive/hover-car-physics?playlist=17120

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Rigidbody))]
public class HoverMotor : MonoBehaviour
{
    public float speed = 90f;       //移动速度
    public float turnSpeed = 5f;    //旋转速度
    public float hoverForce = 65f;  //悬浮力
    public float hoverHeight = 3.5f;//悬浮高度
    private float powerInput;
    private float turnInput;
    private Rigidbody carRigidbody;

    void Awake()
    {
        carRigidbody = GetComponent<Rigidbody>();
    }

    void Update()
    {
        powerInput = Input.GetAxis("Vertical");
        turnInput = Input.GetAxis("Horizontal");
    }

    void FixedUpdate()
    {
        Ray ray = new Ray(transform.position, -transform.up);
        RaycastHit hit;

        if (Physics.Raycast(ray, out hit, hoverHeight))
        {
            float proportionalHeight = (hoverHeight - hit.distance) / hoverHeight;
            Vector3 appliedHoverForce = Vector3.up * proportionalHeight * hoverForce;
            carRigidbody.AddForce(appliedHoverForce, ForceMode.Acceleration);
        }

        carRigidbody.AddRelativeForce(0f, 0f, powerInput * speed);
        carRigidbody.AddRelativeTorque(0f, turnInput * turnSpeed, 0f);
    }
}