#define clkPin 12
#define dataPin 13
#define latchPin 15

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  pinMode(latchPin, OUTPUT);
  pinMode(clkPin, OUTPUT);
  pinMode(dataPin, OUTPUT);

  digitalWrite(latchPin, LOW);

  shiftOut(dataPin, clkPin, MSBFIRST,  0);
  digitalWrite(latchPin, HIGH);
  digitalWrite(latchPin, LOW);
}

void loop() {
  delay(10);
  int8_t i, j;
  byte state = 0;
  for(i=7; i>=0; i--){
    for(j=0; j<i; j++){
      byte temp = state;
      bitWrite(temp, j, 1);
      shiftOut(dataPin, clkPin, MSBFIRST,  temp);
      digitalWrite(latchPin, HIGH);
      digitalWrite(latchPin, LOW);
      delay(50);
    }
    bitWrite(state, i, 1);
    shiftOut(dataPin, clkPin, MSBFIRST,  state);
    digitalWrite(latchPin, HIGH);
    digitalWrite(latchPin, LOW);
    delay(100);
  }
}