The code in this chapter

The code for GameManager.cs:

using UnityEngine;
using System.Collections;

public enum GameState {
  menu,
  inGame,
  gameOver
}

public class GameManager : MonoBehaviour {

  public static GameManager instance;
  public GameState currentGameState = GameState.menu;

  public Canvas menuCanvas;
  public Canvas inGameCanvas;
  public Canvas gameOverCanvas;


  void Awake() {
    instance = this;
  }

  void Start() {
    currentGameState = GameState.menu;
  }
  
  //called to start the game
  public void StartGame() {
    PlayerController.instance.StartGame();
    SetGameState(GameState.inGame);
  }
  
  //called when player die
  public void GameOver() {
    SetGameState(GameState.gameOver);
  }


  //called when player decide to go back to the menu
  public void BackToMenu() {
    SetGameState(GameState.menu);
  }

  void SetGameState (GameState newGameState) {
    
    if (newGameState == GameState.menu) {
      //setup Unity scene for menu state
      menuCanvas...