Time for action – creating a menu scene

Let's create a new file and add a menu scene to our game:

1. Right-click on the src folder and select New | Lua File; call the new file MenuScene.lua.
2. Let's create a class that extends a scene. We first load our own module of all the game's constants (this file already exists in the starter project):

   local constants = require ("constants")

3. Then we build our class:

   local MenuScene = class("MenuScene", function()
       return cc.Scene:create()
   end)
   
   function MenuScene.create()
       local scene = MenuScene.new()
       return scene
   end
   
   function MenuScene:ctor()
       self.visibleSize =  cc.Director:getInstance():getVisibleSize()
       self.middle = {x = self.visibleSize.width * 0.5,  y = self.visibleSize.height * 0.5}
       self.origin = cc.Director:getInstance():getVisibleOrigin()
       self:init()
   end
   return MenuScene

   We'll add the methods next, including the init method we called in the class constructor (always called ctor...