jgenesis-web

Minimal web frontend that compiles to WASM and runs in the browser. Requires a browser with WebGPU support.

Dependencies

Rust Nightly

The web frontend's audio implementation requires sharing memory between the main thread and the audio worklet thread, which is not supported in stable Rust when compiling to WASM. Even in nightly, this requires rebuilding the standard library with atomics support.

Assuming you already have the basic Rust toolchain installed:

rustup toolchain add nightly --component rust-src

wasm-pack

wasm-pack is used to build and package the WASM/JS files. Here it's used mainly just as a convenience wrapper around wasm-bindgen-cli and wasm-opt.

To install:

cargo install wasm-pack

Build

The following incantation builds the required WASM/JS files into the pkg directory:

rustup run nightly \
wasm-pack build --target web . -- -Z build-std=panic_abort,std

The provided build.sh script runs this command for you:

./build.sh

For development, the --dev flag can be used to disable LTOs and wasm-opt, which gives significantly shorter compile times at the cost of larger file size and worse performance:

./build.sh --dev

Run

Copy index.html, the js directory, and the pkg directory into the webserver of your choice.

The webserver must set the following HTTP headers on every request or the application may not work properly in some browsers:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

The provided webserver.py runs a local webserver that automatically sets these headers on every request.

# Binds to localhost:8080 by default
./webserver.py

# Binds to a specific address:port
./webserver.py localhost:9000