sclass RenderFrequencySample_SquareWave extends Meta is RenderFrequencySample {
  public double get(Complex c, double frac) {
    double abs = c.abs();
    if (abs == 0) ret 0;
    frac = frac_nonNeg(frac + c.fracAngle());
    ret abs * (frac < .5 ? 1 : -1);
  }
  
  //@Override
  public void __subtractPeriodFrom(IAddPlateau audio, DoubleRange period, Complex intensity) {
    double goHigh = fracNonNeg(-intensity.fracAngle());
    double abs = intensity.abs();
    double goLow = fracNonNeg(goHigh+.5);
    double t1 = period.start, t2 = period.end, n = l(period);
    bool highFirst = goHigh < goLow;
    double min = min(goHigh, goLow), minPos = t1+min*n;
    double max = max(goHigh, goLow), maxPos = t1+max*n;
    double val = highFirst ? -abs : abs;
    if (metaGet("scaffolding") != null)
      printVars(+t1, +t2, +goHigh, +goLow, +abs, +minPos, +maxPos, +n);
    
    audio.subtractPlateau(t1, minPos,        val);
    audio.subtractPlateau(    minPos, maxPos, -val);
    audio.subtractPlateau(    maxPos, t2,    val);
  }
}