I took a quicklook at your file. If I understand your question, you want the progress bar to respond to moving backwards through the slides as well as forward, and you want it to reset when you click Home to return to the intro slide.
Some issues I see:
First, on the master slide, SL_currentslide should probably be set to Project.SlideNumber instead of Project.SlidesViewed
Next, in the script on that same slide, in the updateSVGRectangle function:
Under if (isSlideExcluded(JS_currentSlide)) and if (currentProgress < maxProgress):
You reset currentProgress to maxProgress. Try commenting these out.
Since you reset currentProgress whenever it decreases, your progress bar never goes down.
Changing these 3 things causes your progress bar to track forward and backward, and reset when you click Home.
Finally, the only other issue is the backward animation. You're using gsap.fromTo(), so the bar is starting at the previously higher value and then decreasing. That may be fine to indicate that your going backward. If you don't want that, you will need to modify the animation function or logic to suit your needs.
A simple solution would be, at the end of the updateSVGRectangle function, to set SL_lastProgress to currentProgress instead of maxProgress. This way, the previous progress variable points to the last slide you visited, and you can animate from there.
That may or may not work for the rest of your needs.
I have attached a .story file with all of the above modifications (marked with a string of asterisks in the script).
Demo: https://360.articulate.com/review/content/db892958-dc47-450b-8a69-58e77017b0b7/review
