class BeatZone{
  FFT fft;
  AudioInput in;
  float [] zone;
  float [] threshold;
  int [] zoneStart;
  int [] zoneEnd;
  boolean [] beat;
  float decay = 0.005;
  BeatZone(FFT fft, AudioInput in, int numZone){
    this.fft = fft;
    this.in = in;
    zone = new float[numZone];
    threshold = new float[numZone];
    zoneStart = new int[numZone];
    zoneEnd = new int[numZone];
    beat = new boolean[numZone];
  }
  void read(){
    for(int i = 0; i < zone.length; i++){
      zone[i] = 0.0;
      beat[i] = false;
      for(int j = zoneStart[i]; j < zoneEnd[i]; j++){
        zone[i] += fft.spectrum[j];
      }
      zone[i] /= zoneEnd[i] - zoneStart[i];
      if(zone[i] > threshold[i]){
        threshold[i] = zone[i];
        beat[i] = true;
      } 
      else {
        threshold[i] = threshold[i] > 0.0 ? threshold[i] - decay : 0.0;
      }
    }
  }
  void setZone(int num, int start, int end){
    zoneStart[num] = start;
    zoneEnd[num] = end;
  }
}