/Stardust-WASM

DDR's Stardust is a falling sand game for the web.

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DDR's Stardust

A nacent falling sand game. This project has been closed due to extreme technical difficulty getting multithreaded Rust to work - for the most recent work, please see the multithreading-issue-reproduction-3 branch.

Some next steps to go on, should anyone feel like chasing them down:

All workers using the same section of linear memory for their stack could result in that bug.

I believe if you use wasm-bindgen, each worker is allocated and told to use a unique section of stack.

As you're not using wasm-bindgen you might have to do it manually yourself?

• https://rustwasm.github.io/2018/10/24/multithreading-rust-and-wasm.html - high level descriptions about what wasm-bindgen does for thread setup

• https://blog.stackblitz.com/posts/thread-destroyer/ - some low level details about $start, $stack_pointer, etc. in WAT (despite focusing on destruction)

(in an optimized build n might be a wasm local, but in an unoptimized debug build I would expect n to spill out to linear memory) —@MaulingMonkey from the Game Development In Rust Discord

A question has also been posted to SO. It seems wasm-bindgen does some Assembly Magic to make this work, so using that would be the next step should anyone like to take it.

I have made a blog post on my personal site, summing development up.

How to Run

Run ./example_server.py on the command line. This will serve the website, setting a few headers required to enable shared memory for the simulation.

Optionally, to rebuild the simulation core with Rust, you'll also need to:

  1. Install rustup.
    1. Optionally, install entr for automatic recompilation. (entr is often in your package manager.)
  2. In the worker directory, run ./compile.sh init. This will set up "nightly" Rust, which we need to build our WASM with imported shared memory.
  3. Run ./compile.sh.

Stardust Options

  • localStorage.devMode = true: Expose world in the global context, for debugging. (May affect other dev-y options too.)
  • localStorage.coreOverride = N: Set the number of processing cores used to N, where N >= 0. If N is 0, processing cores are calculated automatically based on navigator.hardwareConcurrency.