Suggestion: Time scale

[Tomucha]

Hi!

I would like to have "double timeScale" property in RenderLoop. I want player to be able to speed game up or slow it down. It seems to me that this would be pretty straight forward change. Right here:

https://github.com/bp74/StageXL/blob/master/lib/src/display/render_loop.dart#L47

Just multiply deltaTime by timeScale, IMHO.

[bp74]

Hi Tomas,

Do you use the Juggler? You could do something like this:

class TimeLapseJuggler extends Juggler {
  num speed = 2.0;
  bool advanceTime(num time) {
    super.advanceTime(time * speed);
  }
}

var myJuggler = new TimeLapseJuggler();
renderloop.juggler.add(myJuggler);

Now you use this juggler for all your animations. You can also change the the "speed" property to change the speed of the playback.

[bp74]

Btw. this is the prefered technique to implement a "pause" button. You use your own instance of Juggler and if you want to pause the game, you just remove your juggler from the main juggler.

// pause
renderloop.juggler.remove(myJuggler);

// continue
renderloop.juggler.add(myJuggler);

[Tomucha]

Good tip, thanks!

I don't like keeping my own reference to my specialised Juggler, because anyone can call "stage.juggler" and "escape my time scale". Please consider allowing me to create RenderLoop instance with my own "root" Juggler in constructor.

In my case I have overridden RenderLoop itself so I can have this "time scale" behaviour global. (My UI isn't in StageXL, so I don't need any exceptions from this global time scale, and I want to make sure that everything respect it.)

Anyway, thanks again!