// this signal uses the mouseX and mouseY position to build a signal
  class MouseSaw implements AudioSignal
  {
    void generate(float[] samp)
    {
      float range = map(mouseX, 0, width, 0, 1);
      float peaks = map(mouseY, 0, height, 1, 20);
      float inter = float(samp.length) / peaks;
      for ( int i = 0; i < samp.length; i += inter )
      {
        for ( int j = 0; j < inter && (i+j) < samp.length; j++ )
        {
          samp[i + j] = map(j, 0, inter, -range, range);
        }
      }
    }
    
    // this is a stricly mono signal
    void generate(float[] left, float[] right)
    {
      generate(left);
      generate(right);
    }
  }