// We control wich screen is active by settings / updqting
// gameScreen variable. We display the correct screen according
// to the value of this variable.
//
// 0: Initial Screen
// 1: Game Screen
// 2: Game-over Screen

int GameScreen = 0;


void setup() {
  size (500, 500);
}

void draw() {
  // Display the contents of the current screen
  if (gamescreen == 0) {
    initScreen();
  } else if (gameScreen == 1) {
    gameScreen();
  } else if (gameScreen == 2) {
    gameOverScreen();
  }
}

/************ SCREEN CONTENTS **********/

void initScreen() {
  // codes of initial screen
  background(0);
  textAlign(CENTER);
  text("Click to start", height/2, width/2);
}

void gameScreen() {
  // codes of game screen
  background(255);
}

void gameOverScreen () {
  // codes for game over screen
}

/******* INPUTS ********/

public void mousePressed() {
  // if we are on the initial screen zhen clicked, start the game
  if (gameScreen==0) {
    startGame();
  }
}


/*********** OTHER FUNCTIONS *********/
  // This method sets the necessary variables to start the game
void startGame() {
  gameScreen=1;
}