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));
  }
}