How is the ENTER_FRAME event made?

#1

The ENTER_FRAME event is basically what handles openfl’s game loop. It can be useful for updateable instances and I wanna know how it was made.

#2

Its tied into the render loop for our sdl targets. Sdl implements it in that case.

Similarly, for html5 we use the browser api Window.requestAnimationFrame() Window: requestAnimationFrame() method - Web APIs | MDN

The event is created on each frame tick received from each backend implementation and flooded through the display list tree.

There are a few ways to simulate this in haxe like using a while true loop with system breaks. This is a blocking method, though you can leverage multiple threads. Alternatively Haxe provides EventLoop/MainLoop and Timer Apis that relevant here, although accuracy of timing intervals is not always reliable in my experience.

https://api.haxe.org/haxe/MainLoop.html

#3

I’m actually making a class for the event loop called “Updatable”. Where do I start?

#4

What are you actually trying to do?

#5

Trying to remove the old event listener ENTER_FRAME and replacing it with a new one that has a fixed delta.
(And the updatable will have a function named start, that starts the game loop. (I’m targeting it with FlxGame btw)

#6

@SomeGuyWhoLovesHaxe You might want to try using the Timer class: haxe.Timer - Haxe 4.3.3 API
It will let you run a function at any millisecond interval.

#7

It’s worth mentioning that Lime overrides haxe.Timer with its own custom implementation. I’ve found that this can prevent haxe.Timer from running faster than the frame rate in an OpenFL app.

#8

That’s what I’ve did

package fv;

class Updatable {
	public static function start():Void {
		@:privateAccess flixel.FlxG.game.onEnterFrame(new openfl.events.Event("enterFrame"));
		//trace('Tick');
		haxe.Timer.delay(start, Std.int(1000.0 / @:privateAccess Main.framerate));
	}
}
#9

You can instantiate a movieclip like this and add or remove ENTER_FRAME event.

var mc:MovieClip  = new MovieClip();
mc.addEventListener(Event.ENTER_FRAME, ef ) ;

function ef( e:Event )
{
trace ( "This function will loop at the set FPS ") ;
}

To remove :


mc.removeEventListener(Event.ENTER_FRAME, ef ) ;
2 Likes
#10

Ah yes, that’s another solution.