#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// OLED FeatherWing buttons map to different pins depending on board.
// The I2C (Wire) bus may also be different.


// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);
#define C_X 63
#define C_Y 31
float a=45;
float theta_r,x,y;
float x1,y11,x2,y2,t;
int i;
int h=0,m=0;
void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3c); // Address 0x3C for 128x32
  display.display();
  delay(1000);
  display.clearDisplay();
  display.drawCircle(C_X,C_Y,31,SSD1306_WHITE);
  for (i=0;i<360;i+=5){
    t=90-i*6;
    theta_r=t*(PI/180.0);
    x1=C_X+23*cos(theta_r);
    y11=C_Y-23*sin(theta_r);
    x2=C_X+27*cos(theta_r);
    y2=C_Y-27*sin(theta_r);
    display.drawLine(x1,y11,x2,y2,SSD1306_WHITE);
  }
  display.display();
}

void loop(){
  //display.clearDisplay();
  display.drawCircle(C_X,C_Y,31,SSD1306_WHITE);
  for (i=0;i<360;i+=5){
    t=90-i*6;
    theta_r=t*(PI/180.0);
    x1=C_X+23*cos(theta_r);
    y11=C_Y-23*sin(theta_r);
    x2=C_X+27*cos(theta_r);
    y2=C_Y-27*sin(theta_r);
    display.drawLine(x1,y11,x2,y2,SSD1306_WHITE);
  }
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,30);
  display.print(h);
  display.print(":");
  display.print(m);
  //t=(15-h)*30+(15-h)*m/60.0;
  t=90-h*30-m*6/12.0;
  //draw_hours
  //算出度數
  theta_r=t*(PI/180.0);
  x=C_X+15*cos(theta_r);
  y=C_Y-15*sin(theta_r);
  display.drawLine(C_X,C_Y,x,y,SSD1306_WHITE);
  t=90-m*6;
  theta_r=t*(PI/180.0);
  x=C_X+25*cos(theta_r);
  y=C_Y-25*sin(theta_r);
  display.drawLine(C_X,C_Y,x,y,SSD1306_WHITE);
  display.display();
   if (m<59){
      m++;
   }else{
      m=0;
      if (h<12)
        h++;
      else
        h=0;
   }
 display.clearDisplay();
}