Last nuclide may not appear

[KatieWoe]

Test device
Samsung Chromebook and Dell
Operating System
ChromeOS and Win 11
Browser
Chrome
Problem description
For phetsims/qa#828
The last of a nuclide (either proton or neutron) may not appear before it is added to the nucleus. This happens if you are adding them individually or both at once from lower numbers. You can still add the last ones with the buttons, but not by dragging.

Visuals

Troubleshooting information:

!!!!! DO NOT EDIT !!!!!
Name: ‪Build a Nucleus‬
URL: https://phet-dev.colorado.edu/html/build-a-nucleus/1.0.0-rc.8/phet/build-a-nucleus_all_phet.html
Version: 1.0.0-rc.8 2022-08-25 22:49:47 UTC
Features missing: applicationcache, applicationcache, touch
Flags: pixelRatioScaling
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36
Language: en-US
Window: 1280x649
Pixel Ratio: 1.5/1
WebGL: WebGL 1.0 (OpenGL ES 2.0 Chromium)
GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.0 Chromium)
Vendor: WebKit (WebKit WebGL)
Vertex: attribs: 16 varying: 30 uniform: 4096
Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32)
Max viewport: 32767x32767
OES_texture_float: true
Dependencies JSON: {}

[KatieWoe]

Edit, should say last nuclide, not second to last.

[chrisklus]

Thanks @KatieWoe! @Luisav1 and I had some trouble fixing this initially - the problem was occurring because the total count of each nucleon was blipping to the max when it was one smaller than the max because they were being double counted momentarily when being moved from the "particles on their way to the atom" array into the atom itself.

When discussing with @ariel-phet, we had the idea to track these counts just based on "what is out in the play area", instead of worrying about where the nucleons specifically were when out in the play area. Turns out, we were already setup to do this nicely with the particles array on the BANModel.

@KatieWoe could you please confirm on phettest?

[KatieWoe]

This still seems to be happening on phettest.

[chrisklus]

@KatieWoe it's working on phettest for me, do you mind checking if it's a caching problem? thanks!

[KatieWoe]

It shouldn't be since I was in an incognito window, but I'll try one more time.

[KatieWoe]

Ok, it seems ok now, not sure why it wasn't working before, maybe I didn't pull correctly. Sorry about that.

[chrisklus]

For QA: Please close if this is fixed. Thanks!

[Nancy-Salpepi]

This looks good in 1.0.0-rc.10. Closing.

[Nancy-Salpepi]

Sorry I just saw this similar issue with mac + chrome/safari. After U-238 decays, the neutron disappears after a second but the arrow is still active and a neutron can be added.

neutron.disappears.mp4

[Luisav1]

Thanks @Nancy-Salpepi! @chrisklus and I ideally fixed this in the above commit. Could you please check? We also added the "protons=x" and "neutrons=x" query parameters that you can use to get to U-238 quickly.

[Nancy-Salpepi]

@Luisav1 @chrisklus I no longer see the neutron randomly disappearing 🎉 and I love the new proton= neutron = query parameters! Two things:

1. The decrease proton+neutron button size has shrunk

2. There is a delay for the proton at the bottom to disappear when any of the Pa isotopes undergoes beta minus decay (and in the case of Pa-237 it takes a while for the last neutron to appear).

protonneutron.mp4

[Luisav1]

Thanks @Nancy-Salpepi! @chrisklus and I refactored the way the creator node visibility is checked, which fixed the above cases but also changed a lot of other code. We would appreciate thorough testing again on the creator node visibility. Thanks again!

[Nancy-Salpepi]

@Luisav1 @chrisklus things are looking good to me. @KatieWoe is also going to take a look, so please hold off on closing.

[KatieWoe]

I didn't see anything on my end :)

[chrisklus]

Looks like this is good to close, thanks all!