interface RenderFrequencySample {

  public default double get aka renderFrequencySample(Complex c, double frac);

  default void subtractPeriodFrom(IAddPlateau audio, DoubleRange period, Frequency f, Complex intensity) {

    int i1 = ifloor(period.start), i2 = ifloor(period.end);

    new LPair<DoubleRange, Double> pairs;

    for (int i = i1; i < i2; i++)

      addPair(pairs, doubleRangeWithLength(i, 1),

        renderPeriodSample(period, f, intensity, i, false));

    for (DoubleRange r, double amplitude : unpair concatenateAdjacentDoubleRanges(pairs))

      audio.addPlateau(r.start, r.end, amplitude);

  }

  default double renderPeriodSample(DoubleRange period, Frequency f, Complex intensity, double t, bool shouldPrint) {

    double n = l(period);

    Complex c = div(intensity, n);

    double t2 = t-period.start;

    double frac = t2/n;

    if (shouldPrint)

      printVars(+f, +t, interval := n, +t, +t2, frac := formatDouble2(frac),

        c := renderComplexWithAngle(div(c, 32768)));

    /*if (realOnly) c = complex(c.re());

    else if (imagOnly) c = complex(0, c.im());*/

    ret renderFrequencySample(c, frac);

  }

  public default void addPeriodTo(double[] samples, DoubleRange period, Frequency f, Complex intensity) {

    if (samples == null) ret;

    subtractPeriodFrom(new IAddPlateau {

      public void addPlateau(double start, double end, double intensity) {

        int i1 = ifloor(start), i2 = ifloor(end);

        for (int i = i1; i < i2; i++)

          samples[i] += intensity;

      }

    }, period, f, minus(intensity));

  }

}