README.md

CircleTag

A library to generate and read circular tags. Designed to transfer small amounts of data from a phone to another via phone screen and camera. An example use-case could be connecting in-game friends by displaying a tag on one phone and reading it with another.

Project state

Prototype version. I am currently improving the reader to detect the input more easily.

Usage

Put files in your project, and they are ready to use. They do not depend on any special libraries.

byte[] data = Encoding.UTF8.GetBytes("ID#1234");
Generator.Settings settings = new Generator.Settings() {
    Width = 512,
    Height = 512
};
byte[] rgbaImage = Generator.From(data, settings);
byte[] result = Reader.Read(rgbaImage, width, height);
Console.WriteLine(Encoding.UTF8.GetString(result));

Unity Webcam Reading Example

public class UnityTagReaderExample : MonoBehaviour
{
    private WebCamTexture _texture;
    private Texture2D _generatedTexture;
    private Color32[] _pixels;
    private byte[] _bytes;
    
    [SerializeField]
    private RawImage _outputImage;

    private void Start()
    {
        WebCamDevice[] devices = WebCamTexture.devices;
        _texture = new WebCamTexture(devices[0].name);
        _outputImage.texture = _texture;
    }

    private void Update()
    {
        if(_pixels == null)
        {
            _pixels = new Color32[_texture.width * _texture.height];
            _bytes = new byte[_pixels.length * 4];
        }
        _texture.GetPixels32(_pixels);

        for (int i = 0; i < _pixels.Length; i++)
        {
            Color32 pixel = _pixels[i];
            _bytes[i * 4 + 0] = pixel.r;
            _bytes[i * 4 + 1] = pixel.g;
            _bytes[i * 4 + 2] = pixel.b;
            _bytes[i * 4 + 3] = pixel.a;
        }

        byte[] result = CodeReader.Read(_bytes, _texture.width, _texture.height);
        Debug.Log(Encoding.UTF8.GetString(result));
    }
}

Usage screenshot