code: function mapKeyCode(code) {
    var named = {
      8: 'BACKSPACE',
      9: 'TAB',
      13: 'ENTER',
      16: 'SHIFT',
      27: 'ESCAPE',
      32: 'SPACE',
      37: 'LEFT',
      38: 'UP',
      39: 'RIGHT',
      40: 'DOWN'
    };
    return named[code] || (code >= 65 && code <= 90 ? String.fromCharCode(code) : null);
  }
docs: ### Automatic keyboard state  The current keyboard state is stored in `GL.keys`, a map of integer key codes to booleans indicating whether that key is currently pressed. Certain keys also have named identifiers that can be used directly, such as `GL.keys.SPACE`. Values in `GL.keys` are initially undefined until that key is pressed for the first time. If you need a boolean value, you can cast the value to boolean by applying the not operator twice (as in `!!GL.keys.SPACE`).