Shark.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Shark : MonoBehaviour
{
    [SerializeField]
    private Vector3 _dir;

    public float angle = 5f;

    public float speed = 0.3f;

    /// <summary>
    /// サメオブジェクト
    /// </summary>
    [SerializeField]
    private Player _player;

    public string PortName = "/dev/cu.usbmodem1412";
    private const int BaudRate = 115200;
    // https://github.com/baobao/SerialPortWrapper/blob/master/SerialPortWrapper.csを使用しています
    private SerialPortWrapper _serialPortWrapper;

    void OnEnable()
    {
        if (_serialPortWrapper != null)
        {
            _serialPortWrapper.KillThread();
        }

        _serialPortWrapper = new SerialPortWrapper(PortName, BaudRate);
        _serialPortWrapper.onMessageCallback = OnMessage;
    }

    void OnDisable()
    {
        if (_serialPortWrapper != null)
        {
            _serialPortWrapper.KillThread();
            _serialPortWrapper = null;
        }
    }

    void Update()
    {
        _player.transform.Translate(Vector3.forward * speed);
        var q = _player.transform.localRotation;
        _player.transform.localRotation = q * Quaternion.Euler(_dir * angle);
    }

    void OnMessage(string msg)
    {
        if (string.IsNullOrEmpty(msg) == false)
        {
            var array = msg.Split('_');
            if (array.Length == 3)
            {
                // 1023で割って正規化する
                _dir = new Vector3(
                           0,
                           float.Parse(array[0]),
                           0
                       ) / 1023f;
            }
        }
    }
}