Update vars in fromTo()

[ginphreak]

Hi Forum!!

How can I update the "from" values in fromTo() dinamically? Es:

gsap.fromTo(modelCoords,{
  rotZ: -0.3,
  rotX: 0.25,
  rotY: rY,
}, {
  rotZ: 0.5,
  rotX: 0.8,
  rotY: 3,
  scrollTrigger:{
    ...
  }
 });

rotY is update in an animationFrame, so on trigger star I would that rotY starts from its instant value to 3.
Can you help me please?

[GSAP Helper]

Without a minimal demo, it's very difficult to troubleshoot; the issue could be caused by CSS, markup, a third party library, a 3rd party script, etc. Would you please provide a very simple CodePen or Stackblitz that illustrates the issue? 

 

Please don't include your whole project. Just some colored <div> elements and the GSAP code is best. See if you can recreate the issue with as few dependancies as possible. Start minimal and then incrementally add code bit by bit until it breaks. Usually people solve their own issues during this process! If not, at least we have a reduced test case which greatly increases your chances of getting a relevant answer.

 

See the Pen aYYOdN by GreenSock (@GreenSock) on CodePen

that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo: 

 

Using a framework/library like React, Vue, Next, etc.? 

CodePen isn't always ideal for these tools, so here are some Stackblitz starter templates that you can fork and import the gsap-trial NPM package for using any of the bonus plugins: 

• React (please read this article!)
• Next
• Svelte
• Sveltekit
• Vue
• Nuxt

 

Please share the StackBlitz link directly to the file in question (where you've put the GSAP code) so we don't need to hunt through all the files. 

 

Once we see an isolated demo, we'll do our best to jump in and help with your GSAP-specific questions. ✅

[ginphreak]

Thank you for the reply but i solved the problem with this code:

gsap.fromTo(modelCoords,{
  rotZ: -0.3,
  rotX: 0.25,
  rotY: function(){return rY},
}, {
  rotZ: 0.5,
  rotX: 0.8,
  rotY: 3,
  scrollTrigger:{
    ...
  }
 });

 

[ginphreak]

No, unfortunately the problem was only partially resolved. Unfortunately I don't have time to put together a demo. In any case I would only need to know how to update the fromVars at the start of the trigger.

[GreenSock]

Without a minimal demo, we can't do much to help, sorry. Did you set invalidateOnRefresh: true on your ScrollTrigger? 

[Rodrigo]

Hi,

 

The function based values should be a good start but if you want to use some specific value when the ScrollTrigger instance starts maybe you can use the onEnter callback to just create your tween there.

 

For optimization reasons GSAP instances vars are not writable, GSAP just gets the initial values of the element and then iterates between those and the values you passed in the configuration. In this particular case it'll iterate between the values in the from and to objects.

 

Hopefully this clear things up.

Happy Tweening!