all of the alternatives suck. you can complain about egui in particular but immediate-mode libraries have an overwhelming set of advantages and actually scale better with more complex ui.

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ben-schaaf 3 hours ago | parent | next [-]

I work on a GUI toolkit professionally. Immediate-mode libraries are cool, but they absolutely in no way shape or form scale better. Having to evaluate and layout the entire UI for every state change is fundamentally not scalable. Doubly so if you need to do this multiple times to reach a steady-state layout like you do in some cases with egui.

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slopinthebag 3 hours ago | parent [-]

you can cache layouts with immediate mode libraries. in terms of scaling, it really depends - if you have many components updating at once, the benefits of retained mode libraries are diminished if not reversed. when people create demos of 10,000 list elements and updating a single one, it's basically designed as a best case scenario for retained mode. try updating the entire list...

but i can make strong claims about the benefits of not needing to duplicate your state inside of your ui framework. that alone removes an entire category of work, and i would argue scales better from a conceptual/dev standpoint.

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ben-schaaf an hour ago | parent [-]

> you can cache layouts with immediate mode libraries

There's all sorts of caching you can do with immediate mode; like you said, caching the layout in a large list. The end result is the same as retained mode, with all the same complexities. Might as well skip reinventing the thing.

> try updating the entire list...

If you're comparing like-for-like, whether you're doing layout for the entire UI in immediate mode or retained mode shouldn't make a big difference. You're doing the same calculations after all.

> but i can make strong claims about the benefits of not needing to duplicate your state inside of your ui framework

I've found it's often not necessary to duplicate state in the UI framework; you can frequently make UI controls the owner of the state.

	▲	slopinthebag 14 minutes ago \| parent [-]
		to some extent retained mode is a cache invalidation problem. imgui's sidestep this, except for a constrained set of cases where building the ui requires doing a lot of work, in which case a simple, bespoke cache can be used - to me this is far simpler than trying to wrangle your entire application through a generalized state cache abstraction. especially since doing so generally requires you to deeply adopt the UI framework's abstractions into your application code, regardless if it's a good fit or not - like you said, you can avoid duplication, but the tradeoff is massive coupling. i think a glaring red flag with retained mode ui's is how slow they are. there is a reason they put so much effort into granular reactive updates - they're just way too slow otherwise. resize retained mode ui windows and the fps drops to like 2. meanwhile in an imgui, it doesn't matter if you're rendering 1000 buttons and then need to render 1000 dropdowns, the work is roughly identical. this means big problems for a retained mode system. this seems like a massive issue to me - the system is so slow, it's only considered "faster" than imgui (debatable) when it doesn't actually do much. but we want ui's to scale with interactions, not depend on minimal changes in order to recover acceptable performance.

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codedokode 2 hours ago | parent | prev [-]

They are slow and inefficient especially in a VM where there is no GPU. It doesn't make sense to redraw all screen if only one button has changed.

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slopinthebag 2 hours ago | parent [-]

retained mode frameworks still redraw the whole frame typically, unless they're doing some type of partial rendering - that still has a cost though, and all modern ui frameworks retained or not will suffer without a gpu.

in practice rendering a frame of imgui or whatever is so fast and efficient that it's not an issue. we're talking a few thousand triangles and typically a small handful of shaders & draw calls.

	▲	codedokode 2 hours ago \| parent [-]
		How fast are shaders on CPU? Shaders are garbage. I remember many years ago I tried Ubuntu in a VM and it decided to use llvmpipe for rendering. There was a 30-second lag between clicking on anything and seeing the result. Since then I hate GPU-based GUIs.