从iOS通过Unity C＃中的套接字接收以字节为单位的图像

Question

I am trying to send an UIImage from iOS to Unity through sockets. I convert the UIImage to NSData and send it via async socket to a server in Unity.

I am trying to receive all the bytes from the client (the iOS app) and convert these bytes into an image and save it in the computer as an image. I am getting all time error with the file, either is empty or corrupted.

I don't know if it's an error in the iOS side, Unity side, or both.

In my iOS side, I have:

UIImage *img = images[number];
NSData *dataImg = UIImagePNGRepresentation(img);
[asyncSocket writeData:dataImg withTimeout:-1 tag:1]; // Uses GCDA Async Socket library
[asyncSocket disconnectAfterWriting];

In the Unity side, I have:

    // Data buffer for incoming data.
    byte[] bytes = new Byte[1024];

    // host running the application.
    Debug.Log("Ip " + getIPAddress().ToString());
    IPAddress[] ipArray = Dns.GetHostAddresses(getIPAddress());
    IPEndPoint localEndPoint = new IPEndPoint(ipArray[0], 1755);

    // Create a TCP/IP socket.
    listener = new Socket(ipArray[0].AddressFamily,
                          SocketType.Stream, ProtocolType.Tcp);

    // Bind the socket to the local endpoint and 
    // listen for incoming connections.

    try
    {
        listener.Bind(localEndPoint);
        listener.Listen(10);

        // Start listening for connections.
        while (true)
        {
            Debug.Log("Client Connected");

            Socket handler = listener.Accept();

            while (true) {
                bytes = new byte[1024];
                int bytesRec = handler.Receive(bytes);
                data += Encoding.ASCII.GetString(bytes,0,bytesRec);

                Debug.Log("Bytes rec: " + bytesRec);
                if (bytesRec <= 0) {

                    // Save image in folder from bytes
                    File.WriteAllBytes(@"images/img.png",bytes);

                    break;
                }

            }

            //File.WriteAllBytes(@"images/prova.png",dataImg);

            System.Threading.Thread.Sleep(1);
        }
    }
    catch (Exception e)
    {
        Debug.Log(e.ToString());
    }
}

Answer 1

either is empty or corrupted

bytes = new byte[1024]; is not enough to hold an average image. Bump 1024 up to 400,000.

That should be bytes = new byte[400000];

Also, it looks if you do this, other bytes that were not filled will also be written to the file so this might corrupt the png file.

To fix that, replace

System.IO.File.WriteAllBytes(@"images/img.png", bytes);

with

byte []newImage = new byte[bytesRec];
Array.Copy(bytes, newImage, bytesRec);
System.IO.File.WriteAllBytes(@"images/img.png", bytes);

This can be improved later on if it works.