#include <Adafruit_SH110X.h>

Adafruit_SH1106G display = Adafruit_SH1106G(128, 64, &Wire, -1);

#define BUTTON_PIN 3

bool buttonPressed = false;

void setup() {
  display.begin(0x3C);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
}

void loop() {
  display.clearDisplay();

  int buttonState = digitalRead(BUTTON_PIN);

  // LOW means button is pressed, HIGH means button is not pressed
  if (buttonState == LOW) {
    display.fillRect(0, 0, 128, 64, SH110X_WHITE);
  }

  /*
  // Alternate version without the variable:
  if (digitalRead(BUTTON_PIN) == LOW) {
    display.fillRect(0, 0, 128, 64, SH110X_WHITE);
  }
  */

  display.display();
}