#include <U8g2lib.h>
#include <Wire.h> // library requires for IIC communication

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // initialization for the used OLED display


void setup() {
  // put your setup code here, to run once:
  pinMode(A0,INPUT);
  pinMode(A1,INPUT);
  pinMode(A2,INPUT);
  pinMode(A3,INPUT);
  Serial.begin(115200);

  u8g2.begin(); // start the u8g2 library
}

void loop() {
  // put your main code here, to run repeatedly:
  int hall_value_0 = analogRead(A0); // 0 - 1023
  int hall_value_1 = analogRead(A1); // 0 - 1023
  int hall_value_2 = analogRead(A2); // 0 - 1023
  int hall_value_3 = analogRead(A3); // 0 - 1023
  //int percentage_value = (hall_value - 512) / 5.12;
  //int percentage_value = abs(hall_value - 512) / 5.12;
  int percentage_value_0 = round(abs(hall_value_0 - 512) / 5.12);
  int percentage_value_1 = round(abs(hall_value_1 - 512) / 5.12);
  int percentage_value_2 = round(abs(hall_value_2 - 512) / 5.12);
  int percentage_value_3 = round(abs(hall_value_3 - 512) / 5.12);
  //Serial.println(percentage_value);


  //delay(50);

  u8g2.clearBuffer();					// clear the internal memory
  //u8g2.drawXBMP(0, 0, 128, 64, epd_bitmap_image_to_oled); // draw fullscreen image generated by image2cpp website

  //u8g2.drawCircle(16, 16, percentage_value, U8G2_DRAW_ALL); 
  u8g2.drawCircle(16, 16, round(percentage_value_0 * 0.16), U8G2_DRAW_ALL);
  u8g2.drawCircle(16, 16+32, round(percentage_value_1 * 0.16), U8G2_DRAW_ALL);
  u8g2.drawCircle(16+32, 16+32, round(percentage_value_2 * 0.16), U8G2_DRAW_ALL);
  u8g2.drawCircle(16+32, 16, round(percentage_value_3 * 0.16), U8G2_DRAW_ALL);
  //u8g2.setFont(u8g2_font_ncenB14_tr);
  u8g2.setFont(u8g2_font_pressstart2p_8u);

  u8g2.setCursor(0, 20);
  u8g2.print(percentage_value_0);

  u8g2.setCursor(0, 20+32);
  u8g2.print(percentage_value_1);

  u8g2.setCursor(0+32, 20+32);
  u8g2.print(percentage_value_2);

  u8g2.setCursor(0+32, 20);
  u8g2.print(percentage_value_3);

  u8g2.sendBuffer();					// transfer internal memory to the display
  
}