#include "U8glib.h"

/********** OLED parameters *******************************/

//U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE | U8G_I2C_OPT_DEV_0);
U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0 | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST); // Fast I2C / TWI

uint8_t screenWidth = 128;
uint8_t screenHeight = 64;
uint8_t strValue = 0;
uint8_t strIncre = 1;
float rad2grad=57.295779513;
/**********************************************************/

void u8g_prepare(void) {
  u8g.setFont(u8g_font_6x10);
  u8g.setFontRefHeightExtendedText();
  u8g.setDefaultForegroundColor();
  u8g.setFontPosTop();
}

void u8g_line(uint8_t a) {
  u8g.drawStr( 0, 0, "drawLine");
  u8g.drawLine(7+a, 10, 40, 55);
  u8g.drawLine(7+a*2, 10, 60, 55);
  u8g.drawLine(7+a*3, 10, 80, 55);
  u8g.drawLine(7+a*4, 10, 100, 55);
}

void draw(void) {
  u8g_prepare();

  u8g.drawStr( 0, 0, "Webinar 5:");
  u8g.drawFrame(0,10,screenWidth,10);
  u8g.drawBox(0,10,strValue,10);

  float ang_sec = ((strValue*2.8125)/rad2grad);
   
  u8g.drawCircle(screenWidth/2, (screenHeight/2)+10, 20, U8G_DRAW_ALL);
  
  byte xsec = ((screenWidth/2)+(sin(ang_sec)*19)); 
  byte ysec = (((screenHeight/2)+10)-(cos(ang_sec)*19));

  u8g.drawLine(screenWidth/2, (screenHeight/2)+10, xsec, ysec);
}

void setup(void) {
  Serial.begin(115200);

  // flip screen, if required
  //u8g.setRot180();

  //u8g.setFont(u8g_font_unifont);
  //u8g.setFont(u8g_font_ncenR08);
  u8g.setFont(u8g_font_profont12);
  u8g.setColorIndex(1);

  pinMode( A0, INPUT );
}

void loop(void) {
  
  // picture loop  
  u8g.firstPage();  
  do {
    draw();
  } while( u8g.nextPage() );

  strValue = (analogRead(A0)/8);
  if ( strValue >= screenWidth) { strValue = screenWidth; }

  delay(50);
}