Split viewport (e.g. for showing UV layout side by side)

[jdumas]

Hi! I'd like to use polyscope to show UV layout in a 2D view next to a 3D view of the mesh (kinda like Blender). Looking at the doc it doesn't seem possible at the moment? How much of a lift would be required to support that?

[nmwsharp]

Hi! Not supported at the moment, but I would like this feature too :)

It's fairly simple in principle, but would require touching a lot of the core infrastructure. Off the top of my head: (a) some additions to the structure class to indicate what should be shown in which layout view, (b) generalization to the main rendering loop to render each view, and (c) added features to the rendering engine to viewport-composite the views together.

I exchanged messages with someone ~1 year ago who said they were working on it, but I haven't heard from them since so I presume no one is working on this.

[jdumas]

I'm kinda tempted to throw Claude at it based on your feedback, and open up a PR if I can make it work locally. Would that be acceptable?

[nmwsharp]

Fine by me! Let me know how it goes.

With the usual disclosure for AI PRs: please do significantly review the result if you want to open a PR! If there are big changes to huge chunks of the codebase that are difficult for me to review, I may not be willing to merge it; my time is very finite for this. Especially if it feels like it takes more time for me to review than it did for the author to generate :)

(I'm sure you are used to this yourself!)

[jdumas]

Yep, I probably do spend more time reviewing Claude's output than writing code these days 😅

[jdumas]

Alright after some iteration I got something that works, and opened a PR #388. It's missing the "per-viewport structure filtering" in order to implement the "UV Layout" visualization. But the changes in this first PR are minimized to facilitate review (new viewport.h/.cpp and unit test, other file changes are fairly small). Let me know if you'd like to focus on this minimal PR first, or would prefer something more complete in one PR.

I've reviewed the changes but not being familiar with polyscope's internals I'm sure you'll have more to say about potential edge cases. I've tested the demo app locally and I think it behaves correctly now (took some iterating to get there).