Satellite.cs

/******************************************************************************
 * Copyright (c) 2019 wakagomo                                                *
 *                                                                            *
 * This source code is released under the MIT License.                        *
 * http://opensource.org/licenses/mit-license.php                             *
 ******************************************************************************/

using UnityEngine;

/// <summary>
/// オブジェクトを中心に回転し、オブジェクトを向き続ける
/// </summary>
public class Satellite : MonoBehaviour
{
    [Tooltip("回転有無")]
    public bool IsRotate = true;

    [Tooltip("回転中心のオブジェクト")]
    public Transform Target;
    [Tooltip("回転中心からの距離"), Range(0.0f, 2000.0f)]
    public float Distance = 5.0f;

    [Tooltip("回転軸")]
    public Vector3 RotateAxis = Vector3.up;
    [Tooltip("回転速度 (rad/s)"), Range(0.0f, 3600.0f)]
    public float RotateSpeed = 30.0f;

    private void Update()
    {
        if (!IsRotate) return;

        Quaternion rotate = Quaternion.AngleAxis(RotateSpeed * Mathf.PI * Time.deltaTime, RotateAxis);
        Vector3 targetPosition = Target ? Target.position : Vector3.zero;

        transform.forward = rotate * transform.forward;
        transform.position = targetPosition - transform.forward * Distance;
    }
}