#define LED_B 7
#define LED_G 8
#define LED_R 9
#define delay_ 100
int step = 5;
int i_r = 0;
int i_g = 0;
int i_b = 0;

void set_led(int r, int g, int b, int t)
{
  Serial.println(String(r) + ',' + String(g) + ',' + String(b));
  analogWrite(LED_R, r);
  analogWrite(LED_G, g);
  analogWrite(LED_B, b);
  delay(t);
}

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(LED_B, OUTPUT);
  pinMode(LED_G, OUTPUT);
  pinMode(LED_R, OUTPUT);
}

void loop() {
  while (i_r < 255) {
    set_led(i_r,i_g,i_b,delay_);
    i_r += step;
  }
  while (i_g < 255) {
    set_led(i_r,i_g,i_b,delay_);
    i_g += step;
  }
  while (i_b < 255) {
    set_led(i_r,i_g,i_b,delay_);
    i_b += step;
  }
  while (i_r > 0) {
    set_led(i_r,i_g,i_b,delay_);
    i_r -= step;
  }
  while (i_g > 0) {
    set_led(i_r,i_g,i_b,delay_);
    i_g -= step;
  }
  while (i_b > 0) {
    set_led(i_r,i_g,i_b,delay_);
    i_b -= step;
  }
  delay(delay_*10);
  delay(10); // this speeds up the simulation

}