#include <SPI.h>           // Not needed with I2C
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// 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(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void show() { // Often used sequence - Function to simplify code
  display.display(); delay(2000); display.fillScreen(SSD1306_BLACK);
}
void setup() {
  Serial.begin(9600);
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Old Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  
// Initialise variables
  int x0 = 5; // 3 pairs of co-ordinates
  int y0 = 5;
  int x1 = 120;
  int y1 = 23;
  int x2 = 55;
  int y2 = 60;
  int w = 105; // width
  int h = 55;  // height
  int r = 30;  // radius
  int cw = SSD1306_WHITE; // colour white
  int cb = SSD1306_BLACK; // colour black
  int wait = 500; // 2 second delay
  
// Title screen
  display.clearDisplay();
  display.setTextSize(1);             // Normal 1:1 pixel scale
  display.setTextColor(cw);
  display.setCursor(28,25);
  display.println("Screen");
  display.setCursor(28,33);
  display.println("Primitives");
  display.fillScreen(cw);              // Fill screen WHITE
  display.display(); delay(wait); 
  display.fillScreen(cb);              // Fill screen BLACK
  display.display();
  
// Basic Draw & Fill
 
  show();
  display.drawCircle(63, 31, r, cw);
  show();
  display.fillCircle(63, 31, r, cw);
  show();
  display.drawCircle(31, 31, r, cw);
  show();

}

void loop() {
  // put your main code here, to run repeatedly:
}