Experimenting with threading

[JensMunkHansen]

I tried building VTK with pthreads enabled. I got your example to build in development mode. One thing that is puzzling me is that the windows is not properly resized. Also, if I start adding widgets it seems like we have a lot of data races in the JS code.

I could try add a plane widget also in this branch to demonstrate this.

Please don't merge this. It was just to my way to show you the problems that I am facing.

It only runs using npx run dev. Vite is crashing during the production build

[jspanchu]

Hey! Sorry for the very late response here. I was working on enabling threads in a separate branch https://github.com/Kitware/vtkWasmBenchmarks/tree/conesviewer-web-worker but I see you've enabled it here.

[jspanchu]

-sPROXY_TO_PTHREAD and -lembind will not work. Proxying to pthread is only to be used when there is a int main(int, char**) function which performs a long running task. Your best bet is to reorganize the application to create separate threads for rendering and data processing and communicate things from JS to that thread. I don't have a complete example on how to achieve it, but the emscripten tests may have some clues - https://github.com/emscripten-core/emscripten/blob/main/test/gl_in_pthread.cpp

[jspanchu]

Repo has been renamed to vtk-wasm-demos.

And if you're still interested in enabling threads, please take a look at the new async examples in VTK repository. They illustrate both usecases when you use embind and without embind.

1. AsyncClipper - https://gitlab.kitware.com/vtk/vtk/-/tree/master/Examples/Emscripten/Cxx/AsyncClipper
2. WrappedAsyncClipper - https://gitlab.kitware.com/vtk/vtk/-/tree/master/Examples/Emscripten/Cxx/WrappedAsyncClipper