rust-sdl2 VS piston

I don't think that SDL and WGPU are really comparable. You'd be better off comparing SDL to something like Notan or even the SDL bindings for Rust. That said, SDL will have vastly more learning resources than Wgpu or Notan or any Rust alternative. If you know and like rust you can probably use the resources with the Rust SDL bindings.

Those are 3 very different libraries. Are you looking for something in the middle, or do you want all of the features you described? For what it's worth, there's SLD2 bindings for Rust https://github.com/Rust-SDL2/rust-sdl2

There's already a Rust binding for SDL2. See https://crates.io/crates/sdl2

nope. https://github.com/Rust-SDL2/rust-sdl2/issues/884 emscripten target won't work yet either.

it seems like what you are looking for is sdl2 bindings

Dude. It's literally at most 50 lines of code, the entire project. What kind of documentation do you expect me to write? The library I'm using is this one. I don't know why you'd need to know anything about it since it's purely something that can appear literally anywhere, it's part of the language.

*and* SDL2-sys *and* Rust-SDL2

The SDL2 crate had something like this, and it's an option I'm considering. However, if possible, I'd prefer a different, simpler GUI library, so if there's an input-specialized crate out there that does this, I'd love it.

Well, it depends on how you use it; writing to an image buffer isn't much less efficient than writing to any normal buffer (in fact, although displaying your scene to a window efficiently is important, your main bottleneck will be the actual ray tracing loop). You may want to read this article for a practical example of using an ImageBuffer to create and draw a texture with Piston. Other window backends you could use, apart from pixels which was already mentioned in another comment, include minifb and Mini GL, though I haven't personally used them.

And I really like generic systems where you can create a lot of different things. A program that interested me is Piston (https://github.com/PistonDevelopers/piston), I haven't researched it in depth yet, but the concept of being able to create several things with a base and different modules is very interesting

Try Piston

I haven't seen too much on Piston. No idea how active or recent these projects are but I'm still interested in working with it.

Check out their homepage, https://piston.rs, they even show off some great examples of how their library has been used!

Before I could implement the display output, I needed something to draw the images onto. There are quite a few Rust crates available to create a GUI window and update it with 2D graphics. Most of these are of course intended for making games, and also include ways of getting key presses as input, which I'll also need. I looked at Piston, which I've used before on other projects, Macroquad, which also supports web assembly as well as desktop targets, Pixels, which is intended specifically for 2D games, and Minifb, which is also specifically for 2D applications, but is much simpler. I also tried out libretro, which is specifically made for video game emulation, but I found it much more restrictive than the others because of it's narrow focus.

Depends on my goals. I year ago I wanted to learn rust, so I used piston for a gamejam. (There are several rust engines including bevy, piston, amethyst. They probably vary in quality, features, and constraints.) Piston was a terrible experience because compilation is slow even on that tiny project.

Piston