XNA Hacks - Simple Automatic TextureAtlas Helper

    public class TextureAtlas
    {
        private readonly Dictionary<Texture2D, Rectangle> _atlasData = new Dictionary<Texture2D, Rectangle>();

        private readonly Texture2D _texture;

        public Texture2D Texture { get { return _texture; } }

        private int _x, _y, _nextY;

        public TextureAtlas(GraphicsDevice graphicsDevice, int width, int height)
        {
            _texture = new Texture2D(graphicsDevice, width, height);
        }

        public void RegisterTextures(IEnumerable<Texture2D> textures)
        {
            foreach (var texture in textures)
            {
                RegisterTexture(texture);
            }
        }

        public void RegisterTexture(Texture2D texture)
        {
            // NOTE: This is a simple proof-of-concept implementation
            if (_atlasData.ContainsKey(texture))
            {
                return;
            }

            if (texture.Width + _x >= _texture.Width)
            {
                _x = 0;
                _y = _nextY;
            }

            _atlasData[texture] = BlitTexture(_texture, texture, _x, _y);

            _x += texture.Width;
            _nextY = Math.Max(_nextY, _y + texture.Height);
        }

        public bool LookUp(Texture2D source, out Texture2D result, out Rectangle textureRectangle)
        {
            textureRectangle = new Rectangle(0, 0, source.Width, source.Height);

            if (_atlasData.ContainsKey(source))
            {
                result = _texture;
                textureRectangle.X = _atlasData[source].X;
                textureRectangle.Y = _atlasData[source].Y;
                return true;
            }

            result = source;
            return false;
        }

        private Rectangle BlitTexture(Texture2D destinationTexture, Texture2D sourceTexture, int x, int y)
        {
            var buffer = new Color[sourceTexture.Width*sourceTexture.Height];
            sourceTexture.GetData(buffer);

            var dest = new Rectangle(x, y, sourceTexture.Width, sourceTexture.Height);
            destinationTexture.SetData(0, dest, buffer, 0, buffer.Length);

            return dest;
        }
    }