ScreenSaver

using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System;

public class ScreenSaver : MonoBehaviour {

    byte[] receiveArr;
    bool writeFile = false;
    int index = 0;
    int allCount = 0;

    List<byte[]> list = new List<byte[]>();
    public string nameFile;

    void WritePng()
    {
        writeFile = false;
        int indexArr = 0;
        for (int i = 0; i < list.Count; i++)
        {
            for (int j = 0; j < list[i].Length; j++)
            {
                indexArr++;
            }
        }

        receiveArr = new byte[indexArr];
        indexArr = 0;

        for (int i = 0; i < list.Count; i++)
        {
            for (int j = 0; j < list[i].Length; j++)
            {
                receiveArr[indexArr] = list[i][j];
                indexArr++;
            }
        }

        File.WriteAllBytes(nameFile+".png", receiveArr);
    }

    // Update is called once per frame
    void Update() {
        if (writeFile)
        {
            WritePng();
        }

        if (Input.GetKeyDown(KeyCode.Space))
        {
            WritePng();
        }

        if (Input.GetKeyDown(KeyCode.P))
        {
            StartCoroutine(UploadPNG());
        }
    }

    IEnumerator UploadPNG()
    {
        yield return new WaitForEndOfFrame();
        Texture2D texture = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, false);
        texture.ReadPixels(new Rect(0, 0, Screen.width, Screen.height), 0, 0, false);
        texture.Apply();

        byte[] bytes = texture.EncodeToPNG();

        Destroy(texture);

        int lengthPacket = 255;

        int countOfMessage = bytes.Length / lengthPacket;
        int remainder = bytes.Length % lengthPacket;

        byte idMessage = 0;
        byte[] temp;
        int startIndex = 0;
        int receiveCount = countOfMessage + ((remainder > 0) ? 1 : 0);

        for (int i = 0; i < receiveCount; i++)
        {
            temp = new byte[lengthPacket + 9];
            temp[0] = idMessage;


            byte[] numberOfPacket = BitConverter.GetBytes(i);
            temp[1] = numberOfPacket[0];
            temp[2] = numberOfPacket[1];
            temp[3] = numberOfPacket[2];
            temp[4] = numberOfPacket[3];


            byte[] allPacket = BitConverter.GetBytes(receiveCount);
            temp[5] = allPacket[0];
            temp[6] = allPacket[1];
            temp[7] = allPacket[2];
            temp[8] = allPacket[3];

            if (i < countOfMessage)
            {

                Array.Copy(bytes, startIndex, temp, 9, lengthPacket);

                startIndex += lengthPacket;
            }

            if (i >= countOfMessage && remainder > 0)
            {
                temp = new byte[9 + remainder];

                Array.Copy(bytes, startIndex, temp, 9, remainder);
            }
            Debug.Log(i);
        }
        byte[] end = new byte[] {0, 0, 0, 0, 0, 0, 0, 0, 0 };

        Debug.Log(countOfMessage + "  " + remainder);

        File.WriteAllBytes(Application.dataPath + "/../"+nameFile+".png", bytes);

        Debug.Log("File is saved");
    }
}