#include <Adafruit_SSD1306.h>

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire);

#define UP 2
#define DOWN 3
#define LEFT 4
#define RIGHT 5

int dx = 0;
int dy = 0;

void drawAxes() {
  display.clearDisplay();

  display.setTextColor(SSD1306_WHITE);

  display.drawLine(64 + dx, 0, 64 + dx, 64, SSD1306_WHITE);

  display.drawLine(0, 32 + dy, 128, 32 + dy, SSD1306_WHITE);

  display.display();
}

void drawPoint() {
  
  display.fillCircle(64, 32, 2, SSD1306_WHITE);
  
  display.display();
}


void moveAxes() {
  
  int up = digitalRead(UP);
  int down = digitalRead(DOWN);
  int left = digitalRead(LEFT);
  int right = digitalRead(RIGHT);

  if (up == HIGH && dy > -31)
    dy--;
  if (down == HIGH && dy < 32)
    dy++;
  if (left == HIGH && dx > -64)
    dx--;
  if (right == HIGH && dx < 64)
    dx++;
}


void showCoordinates() {

  int x = -dx;
  int y = -dy;

  display.setTextColor(SSD1306_WHITE);

  display.setCursor(0, 55);
  display.print("(");
  display.print(-x);
  display.print(", ");
  display.print(y);
  display.print(")");

  display.display();
}

void setup() {

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);

  pinMode(UP, INPUT);
  pinMode(DOWN, INPUT);
  pinMode(LEFT, INPUT);
  pinMode(RIGHT, INPUT);

  drawAxes();

  showCoordinates();
}

void loop() {

  moveAxes();

  drawAxes();

  showCoordinates();
}