This forum is read only and just serves as an archive. If you have any questions, please post them on

1 decade ago by Bradley

Recently, Greensock released a JavaScript version of their popular ActionScript tweening suite. I have worked with the ActionScript version, and have been experimenting using the new release in Impact. It has worked out well.

I don't know how familiar the Impact community is with Greensock, or other tween engines, but I believe this new release should have a strong influence on Impact development.

There is a key difference in the way Impact and TweenLite handle time and updates. If I am understanding correctly, both handle frame dropping gracefully, but only Impact has a settable, maximum allowed dropped frames. This difference should be expected to cause the two engines to get out of sync, which may not be a problem for some things, but a solution should be worked out to allow for integration of these two great tools.

1 decade ago by Bradley

So I actually figured out how to get the Impact engine to trigger updates to TweenLite (or TweenMax), and for TweenLite to look to Impact for it's time code.

1. Change this:

_getTime = || function() {return new Date().getTime();};

to this;

_getTime = function () {
    return (ig.system) ? * 1000 :  0;

2. Comment out the two lines in TweenLite that look like this:

_id = _req( _self.tick );

3. In the run function for add this as the first line:


Please note that these mods worked for the beta (v12) version. Please shoot an email to bradley( at ) if you have any problems.

1 decade ago by solidgoldrobot

Has anyone had success using Greensock with Impact? Looking for some examples to use for guidance.

1 decade ago by y0ungb0b

I tried out the instructions above using TweenMax and got it to work. I ran into some problems.

On my title screen I create an ig,font object. I want the text to continuously fade in and out so I do this in Init and it works:, 1, {alpha: 0, ease:Power2.easeInOut, repeat: -1, yoyo: true})

I play some music and try this and it works:, 4, {volume: 0, ease:Power2.easeInOut, repeat: -1, yoyo: true})

In Init, I spawn an Entity and try this:, 1, {pos: {y:200}, ease:Power2.easeInOut, repeat: -1, yoyo: true})

This does not work. The entity doesnt draw. If I check out its pos.x and pos.y it shows NaN.

Could anyone please tell me what im doing wrong?

1 decade ago by y0ungb0b

After a re-freshed pair of eyes, solved:

Work on the pos object to get rid of the NaN., 1, {y: 200, ease:Power2.easeInOut, repeat: -1, yoyo: true})

Then make sure you override the update() for the entity so Impact doesnt do any physics stuff.

1 decade ago by y0ungb0b


It looks like the timing in GS has been updated since I last used it.

_id = _req( _self.tick );

This line doesn't exist anymore. Can anybody help to fix the latest version of GS to use impacts ticker?
Page 1 of 1
« first « previous next › last »