Access to flash.display.stage in Starling

maru

Hi,

For my starling Stats class I need to get access to the flash.display.Stage::frameRate property, since there is no such property in the Starling stage...

I did a dirty trick to get access to native stage, but I don't really like it :

// dirty hack to access the flash.display.stage in Starling
dummy = new Shape();
Starling.current.nativeOverlay.addChild(dummy);
Starling.current.nativeOverlay.addEventListener(flash.events.Event.ADDED_TO_STAGE, onNativeOverlayAdded);

protected function onNativeOverlayAdded(event:flash.events.Event):void
{
	Starling.current.nativeOverlay.removeEventListener(flash.events.Event.ADDED_TO_STAGE, onNativeOverlayAdded);
        // now we can get access to Starling.current.nativeOverlay.stage
        var nativeStage:flash.display.Stage = Starling.current.nativeOverlay.stage;
        // clean
	Starling.current.nativeOverlay.removeChild(dummy);
	dummy = null;
}

// Here is the guilty one : see Starling.as, line 261
private function updateNativeOverlay():void
{
   mNativeOverlay.x = mViewPort.x;
   mNativeOverlay.y = mViewPort.y;
   mNativeOverlay.scaleX = mViewPort.width / mStage.stageWidth;
   mNativeOverlay.scaleY = mViewPort.height / mStage.stageHeight;

   // Having a native overlay on top of Stage3D content can cause a performance hit on
   // some environments. For that reason, we add it only to the stage while it's not empty.

   var numChildren:int = mNativeOverlay.numChildren;
   var parent:flash.display.DisplayObject = mNativeOverlay.parent;

// comment : these lines removes the nativeOverlay from display list
// when it has no children
   if (numChildren != 0 && parent == null)
       mNativeStage.addChild(mNativeOverlay);
   else if (numChildren == 0 && parent)
       mNativeStage.removeChild(mNativeOverlay);
}

It would great to have access to the nativeStage via the Starling.as class, which has already a private property mNativeStage:flash.display.Stage that can not be null (see the Starling.as constructor)... Maybe a static getter would be convenient !

Nicolas

Daniel

Ah, you're right, that property should have been there from the start. (BTW, brilliant workaround! *g*)

I just added the property to the latest GitHub version of Starling!

https://github.com/PrimaryFeather/Starling-Framework/issues/29

thibault.imbert

And I updated the mini-book, in revision 1.2, accessing the native stage through nativeStage is covered :

http://www.bytearray.org/wp-content/projects/starling/Introducing%20Starling%20-%20rev%201.2.pdf

Thibault

Daniel

Awesome, Thibault! Thx =)

maru

This is great guys ! Thank you for your quickness 😉

milo

Hi,

I'm writing an application where objects in a classic pathanimation trigger the movement
of a big map in Starling. What would be the best way of communication & layering.
Pushing the classic flash displayList into the nativeOverlay or in a layering the Starling
under the standard flash displayList. Without the nativeOverlay - how can the MainClass and the Starling rootClass communicate ?

Thanks,

-milo

Daniel

Hm, I'm not sure I understand your question correctly -- could you perhaps rephrase it?

If you want to access Starling from within your conventional Flash display objects (without the native overlay), then you need access to the Starling stage -- I just saw that that property was missing. I just added it:

https://github.com/PrimaryFeather/Starling-Framework/issues/31

Now you can access the Starling stage via

var stage:starling.display.Stage = Starling.current.stage;

(Available if you pull/download the head revision of the Starling repository.)

I hope that helps!

milo

Hey Daniel,
thanks for the quick answers allover the forum…

To rephrase it.
Top-layer: standard flash displayList / cpu - objects including video controlling the
Bottom-layer: Starling Stage3d level / gpu.

So the Application-MainClass (hosting the Starling instance) needs to call methods inside the Starling rootClass -
and the Starling rootClass needs to call methods in the MainClass (or bubble Events).

I hope I clarified my target.

Thanks,

-milo

Daniel

Ah, OK! Thanks for rephrasing it =)

In that case, you can now (with the head revision of the git repository) get the Starling stage from your standard flash classes:

var stage:starling.display.Stage = Starling.current.stage;

then you get your root game class: it will always be the first child of the stage.

var myGame:MyGame = stage.getChildAt(0) as MyGame;

With that instance, you should be able to do everything you need. To go the other direction, you can either add all your Flash content to the "nativeOverlay" object, which would allow you to access your Flash content from Starling; or you simply save an instance to your Flash sprite in the Starling game class manually, to access it later, e.g.

// somewhere in your Flash class
var stage:starling.display.Stage = Starling.current.stage;
var myGame:MyGame = stage.getChildAt(0) as MyGame;
myGame.flashRoot = this;

I hope that helps!
Daniel

jonny-starling

Hi Daniel,

I tried to reference the Starling game object from my Flash Class like you suggest:
var myGame:MyGame = stage.getChildAt(0) as MyGame;

But I get an invalid child index error. It seems to be a timing issue because I can see that myGame's numChildren is zero at this point. If I add an onenterframe this becomes 1 in the next frame.

I can do a hacky onenterframe fix for this but im wondering if there is a more elegant solution?

Thanks

Daniel

Mhm, your "MyGame" instance will only be initialized when Starling is done with all its internal setup procedures. That's also the reason why you don't pass a "MyGame" instance directly to Starling in its constructor, but only its class: you don't want any of your code to run before Starling is configured, and that way, Starling can take care of that.

So you can either use the enter frame event handler, as you're doing already -- because when it is called, Starling is guaranteed to be initialized. Or you can add an event listener to the Stage3D context, as Starling does:

stage3D.addEventListener(Event.CONTEXT3D_CREATE, onContextCreated);

If you add that event listener after creating the Starling object, it will be called immediately when Starling is ready!

Daniel

BTW, you get the stage3D object by calling

var stage3D:Stage3D = stage.stage3Ds[0];

("stage" being the conventional Flash stage, not that of Starling.)

jonny-starling

great - thanks!

Daniel

You're welcome! =)

nashnie

:-)thanks!

grit

I must say this did not really work for me. I use an 'old' trick to share some variables through flash classes which also worked in the starling communication:

I create a class GlobalVars:

package
{
public class GlobalVars
{
public static var vars:Object = {};
}
}

I put in the main Flash class some shizzle concerning stage init and such, when I'm sure the stage is there i copy it into the GlobalVars' vars-object:

GlobalVars.vars.mStage=this;

After that I can just call root functions from anywhere:

GlobalVars.vars.mStage.myFunction(<someparameter>);

Maybe a bit neater:
MovieClip(GlobalVars.vars.mStage).myFunction(<someparameter>);

but then be sure the starling movieclip does not interfere with the flash movieclip