Difficult to place particle on third energy level

[Nancy-Salpepi]

Test device MacBook Air M1 chip

Operating System 13.5.1

Browser Safari 16.6

Problem description For https://github.com/phetsims/qa/issues/977, on the Chart Intro screen when manually placing a neutron (or proton) on the third energy level, if I let go above the level it drops back to the collection area rather than falling to the third energy level. I don't see this same behavior with the first or second energy level.

Steps to reproduce

1. Press the Add Proton + Neutron button 8 times to fill the first 2 energy levels
2. Grab a neutron (or proton) and release it slightly above the third energy level

Visuals

https://github.com/phetsims/build-a-nucleus/assets/87318828/710bb0cc-b422-4939-b6e2-86a41268e910

Troubleshooting information: !!!!! DO NOT EDIT !!!!! Name: ‪Build a Nucleus‬ URL: https://phet-dev.colorado.edu/html/build-a-nucleus/1.0.0-dev.23/phet/build-a-nucleus_all_phet.html Version: 1.0.0-dev.23 2023-09-12 15:57:17 UTC Features missing: applicationcache, applicationcache, touch Flags: pixelRatioScaling User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15 Language: en-US Window: 1317x706 Pixel Ratio: 2/1 WebGL: WebGL 1.0 GLSL: WebGL GLSL ES 1.0 (1.0) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 30 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32) Max viewport: 16384x16384 OES_texture_float: true Dependencies JSON: {}

[zepumph]

@Luisav1, we have talked about this in the past. It is because the origin of particles is in the top left right? I feel like the dilation on the bottom side is not like this. We likely want to dilate some checking logic to account for an extra diameter on the top of the ShellNucleus lines.

[KatieWoe]

I was running in to this as well.

[zepumph]

I plotted the view bounds of the modelViewTransform, and things look REALLY great:

https://github.com/phetsims/build-a-nucleus/blob/f13d1442601da590917b2eaf02b6f0ba5709530e/js/chart-intro/model/ShellModelNucleus.ts#L50-L53

So this is more about the capture area logic when releasing mouse drag. I'll take a look.

[zepumph]

This is the new capture area:

@Nancy-Salpepi will you review main and feel free to close.

[Nancy-Salpepi]

@zepumph it is definitely better, but maybe the capture area still needs to be a teensy bit higher? @KatieWoe what do you think?

https://github.com/phetsims/build-a-nucleus/assets/87318828/82a952fe-1d97-4bcc-8cb1-853285b0261e

[KatieWoe]

It seemed ok to me using a mouse.

[zepumph]

Makes sense to me, here is another particle-radius's worth of increase. What do you think?

[Nancy-Salpepi]

Thanks @zepumph! I like it!