Metronome class in processing (BPM, beat)

Metro.pde

class Metro {
  float bpm;
  float nextTime = 0;
  int mode = 0;
  int modeNum;
  
  Metro(float _bpm, int _modeNum) {
    bpm = _bpm;
    modeNum = _modeNum;
  }
  
  int metro() {
    float timer = bpm * 100/6; // interval of mode
    if (millis() > nextTime) {
      mode++;
      if (mode > (modeNum - 1)) {
        mode = 0;
      }
      nextTime = millis() + timer;
    }
    return mode;
  }
}

sketch_2_metro.pde

Metro metro1;

void setup() {
  size(300, 300);
  metro1 = new Metro(60, 3);
}

void draw() {
  background(210);
  int _mode = metro1.metro();  
  //println(mode);
  fill(0, 200);
  textSize(42);
  textAlign(CENTER);
  text(_mode, width/2, height/2);
  //saveFrame("frames/#####.tif");
}