using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.IO;
using UnityEngine.UI;

//指令碼功能：截圖，截圖帶UI

public class ScreenShot : MonoBehaviour
{
    public void OnscreenShotClick()
    {
        //獲取系統時間
        System.DateTime now = System.DateTime.Now;
        //時間轉換成字串來儲存
 

        string times = now.ToString();
        times = times.Trim();
        times = times.Replace("/", "-");
        //命名圖片名
        string fileName = "ARScreenShot" + times + ".png";
        //判斷系統是否安卓平臺
        if(Application.platform == RuntimePlatform.Android)
        {　　

            //擷取螢幕，new一個貼圖放截圖
 

            Texture2D texture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, false);
            //讀取貼圖
            texture.ReadPixels(new Rect(0, 0, Screen.width, Screen.height), 0,0);
            texture.Apply();
            //貼圖轉換成位元組陣列
            byte[] bytes = texture.EncodeToPNG();
            
 
//存放目錄
            string destination = "/sdcard/DCIM/ScreenShots";
            //判斷目錄是否存在，不存在則建立
            if (!Directory.Exists(destination))
            {
                Directory.CreateDirectory(destination);
            }
            string pathSave = destination + "/" + fileName;
            //存圖片
            File.WriteAllBytes(pathSave, bytes);
        }
    }
}

1. 指令碼命名為ScreenShot
2. 把指令碼掛到某個object上，如canvas
3. button按鈕on click()新增，選擇指令碼OnscreenShotClick()函式；

（程式碼存檔，以備不時之需）

不帶UI的，在以上程式碼修改

程式碼如下

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.IO;
using UnityEngine.UI;

//指令碼功能：截圖

public class ScreenShot : MonoBehaviour
{
    private Camera arCamera;

    // Start is called before the first frame update
    void Start()
    {
        arCamera = GameObject.Find("ARCamera").GetComponent<Camera>();
    }

    // Update is called once per frame
    void Update()
    {
        
    }
    public void OnscreenShotClick()
    {
        //獲取時間
        System.DateTime now = System.DateTime.Now;
        //時間轉換成字串來儲存
        string times = now.ToString();
        times = times.Trim();
        times = times.Replace("/", "-");

        string fileName = "ARScreenShot" + times + ".png";

        if(Application.platform == RuntimePlatform.Android)
        {
            RenderTexture rt = new RenderTexture(Screen.width, Screen.height, 1);
            arCamera.targetTexture = rt;
            arCamera.Render();

            RenderTexture.active = rt;

            
            //new一個貼圖放截圖
            Texture2D texture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, false);
            //讀取貼圖
            texture.ReadPixels(new Rect(0, 0, Screen.width, Screen.height), 0,0);
            texture.Apply();

            arCamera.targetTexture = null;
            RenderTexture.active = null;
            Destroy(rt);

            //貼圖轉換成位元組陣列
            byte[] bytes = texture.EncodeToPNG();

            //
            string destination = "/sdcard/DCIM/ScreenShots";

            //
            if (!Directory.Exists(destination))
            {
                Directory.CreateDirectory(destination);

            }
            string pathSave = destination + "/" + fileName;
            File.WriteAllBytes(pathSave, bytes);

            

        }


    }
}