Can't build for web about raycaster-rust

[elo-siema]

Update: I got it to compile and run the main loop in the browser by using the mechanism for starting emscripten main loop from here , but all I see is black rectangle on the page :/
The functions:

self.canvas.copy(&texture, None, None).unwrap();
self.canvas.present();

are being called, but there's no output on the canvas.
I'd really appreciate if you had some info on the tried & true toolkit.

[elo-siema]

Update: This branch: https://github.com/elo-siema/hyperbolic-raycaster-rust/tree/web-build
Manages to render the first frame, and then panics:

thread panicked while processing panic. aborting. raycaster.js:2351:16
exception thrown: RuntimeError: unreachable executed,std::panicking::rust_panic_with_hook::h4771cee0d781dbd0@http://localhost:6931/raycaster.wasm:wasm-function[685]:0x217ca

I'm almost certain this has something to do with Emscripten mishandling references captured in the main loop lambda, losing them from iteration to iteration. Main loop function called like

loop{
...
}

works fine and tries to render frames (just doesn't show them due to blocking of thread).

Once during experiments I saw this piece of code (called from main_loop in emscripten)

let width =window.view.canvas.window().size().0;
let height = window.view.canvas.window().size().1;
println!("{}, {}", width, height);

output "0, 0" and panic on a next line trying to manipulate the canvas.

This looks to me like a severe regression bug in Emscripten.

[elo-siema]

Update: Managed to solve it on my fork. Definitely an issue with Emscripten main loop.
https://elo-siema.github.io/hyperbolic-raycaster-rust/