How to call sceneManager from sub screen

nextgamevertex

Hi all,
I am using SceneManager to change between screen but i do not know how to call sceneManager:changeScene from sub screen. Currently I pass changeScene via userData:

local sceneManager = SceneManager.new({ ["Main"] = Main, ["MainMenu"] = MainMenu, ["ChooseYourDifficulty"] = ChooseYourDifficulty, ["ChooseYourType"] = ChooseYourType, ["Succeed"] = Succeed, ["HighScoreScreen"] = HighScoreScreen, })     stage:addChild(sceneManager)   -- load first scene   sceneManager:changeScene("MainMenu", 1, SceneManager.moveFromLeft, easing.outBounce, {userData = {sceneManager=sceneManager}})

And then in MainMenu I get sceneManager back:

function MainMenu:init(params) if params then sceneManager = params.sceneManager; end   //.... and then call btnFreePlay:addEventListener("click", function() sceneManager:changeScene("ChooseYourDifficulty", 1, SceneManager.moveFromLeft, easing.outBounce, {userData = {sceneManager=sceneManager}}) end )

Is this right approach?

Thanks!

bowerandy

@nextgamevertex, well you could do that but what I do is this...

I generally have a class that represents my overall game/program, and it is this that holds on to the scene manager. This game class, I make a singleton (i.e. a class that can only have one instance) and I hold onto this instance in a "sharedInstance" field of the class object itself.

It's probably easier to show you than explain. Here's a bit of a recent demo I wrote that uses scenes. This is the init() for my game class (called BhWaxSceneDemo):

function BhWaxSceneDemo:init() self.sceneManager=SceneManager.new({ ["scene1"]=DemoScene1, ["scene2"]=DemoScene2, })   self.sceneManager:changeScene("scene1") stage:addChild(self.sceneManager)   BhWaxSceneDemo.sharedInstance=self end

Now in my scene classes I can reference the scene manager like this:

function DemoScene2:onButtonClicked() BhWaxSceneDemo.sharedInstance.sceneManager:changeScene("scene1", 1, SceneManager.moveFromLeft) end

I find that in most games, you need to have a central place to store general stuff about the game; high scores, and other global stuff. It seems sensible to keep the scene manager in there too.

Purists sometimes complain about using the Singleton pattern because it effectively creates a global and globals are frowned upon. However, since we already have each class as a global in Gideros, I feel this is an acceptable and convenient approach.

BTW, use of the (rather lengthy) name "sharedInstance" is by no means mandatory. I only choose this because that's what people programming in IOS typically use. Another name might be "current".

best regards

zaniar

I always make sceneManager global

nextgamevertex

@bowerandy thanks so much! I will try this.

Edit: Please review this, is this acceptable?

main.lua

GameGlobal.new();

GameGlobal.lua

GameGlobal = Core.class();   function GameGlobal:init() self.sceneManager = SceneManager.new({ ["Main"] = Main, ["MainMenu"] = MainMenu, ["ChooseYourDifficulty"] = ChooseYourDifficulty, ["ChooseYourType"] = ChooseYourType, ["Succeed"] = Succeed, ["HighScoreScreen"] = HighScoreScreen, })   stage:addChild(self.sceneManager) -- load first scene self.sceneManager:changeScene("MainMenu", 1, SceneManager.moveFromLeft, easing.outBounce) GameGlobal.sharedInstance=self end

MainMenu.lua

// ..... btnFreePlay:addEventListener("click", function() GameGlobal.sharedInstance.sceneManager:changeScene("ChooseYourDifficulty", 1, SceneManager.moveFromLeft, easing.outBounce, {userData = {sceneManager=sceneManager}}) end )

bowerandy

@nextgamevertex, yes that looks how I'd do it.

best regards

anhtuank7c

Thank you.
It so helpful.