Sun Motion sim: Add fixes for current version of three.js

There have been many three.js changes since this app was last built - these required some changes in our code to fix the scene up.

https://github.com/mrdoob/three.js/wiki/Migration-Guide

Don't know if we want to keep it but the shadowed area is missing from this update. Screenshots:

Oh weird, I thought the shadow was visible on my system. We definitely want to keep that - I will investigate.

So, my scene with these changes looks pretty different from yours - I've tested in Firefox and Chrome:

Another problem with your scene is overall lighting issue, which should have been addressed by these changes.

It could be a video card issue, with this webGL stuff. I am on a much older system, so it's possible it's behaving differently. But, are you sure you're running the right version of the code here? This PR includes the updated, compiled bundle.js and you shouldn't have to do any special build process here.

I just tried running it again, same issue. But maybe it is on my end. Do you want to push this out and see how it runs on the github page?

That's okay, there's no rush for these changes to go out. I'll see if I can reproduce this issue on other systems, like at home, or on a mac.

@ndittren I have rebased this branch and done another build on the current version of threejs this simulation is using (0.155.0). There were lighting changes in threejs before this that necessitate some of the changes in the code here - and things are looking on my system:

I'm curious how they look on your Mac on this branch.

@nikolas pretty much the same. There is this slight hiccup with the stick figure in the second screenshot

I think the original issue was the missing shading around the globe. But it looks fine without it really.

Cool! Yeah there is some weirdness with that shadow that has been introduced through three.js updates - it is also supposed to be in the shape of the stick figure instead of a block, but that's a minor thing. I think we can move forward with these changes and i can finally make an updated build for this sim as it looks like the last one was done in 2021.