Shipping

WebAssembly

The target that lets a patch run in a browser — and what the runtime learns from the manifest.

Anyone who wants a patch on a web page.

./build/polec fx.pole --emit=web --out=fx

An object targeting wasm32, plus a JSON manifest. Link the object with wasm-ld and the manifest tells the browser everything the C header would have told C.

This is what the runnable blocks on this site are. Press Run on an oscillator and the real compiler produces a real wasm module, which a real AudioWorklet runs.

Compile, link, then host#

There are three steps between a Pole file and sound from a web page:

Compile the patch into a wasm-targeted object and a manifest.
Link that object into a .wasm module, resolving its maths functions.
Host the module in an audio runtime that supplies memory, controls and an audio callback.

From tools/pole, with wasi-sdk available, the repository's linker helper performs the second step:

./build/polec examples/gain.pole --emit=web --out=/tmp/gain-web
python3 scripts/link_wasm.py /tmp/gain-web

File	Purpose
`gain-web.o`	Intermediate wasm object, not yet the browser-loadable module.
`gain-web.json`	Manifest describing symbols, storage and controls.
`gain-web.wasm`	Linked module loaded by the browser runtime.

Set POLE_WASI_SDK to your SDK directory if it is outside the helper's usual locations. Exporting these files does not create a finished web player. This site supplies that player through its AudioWorklet and the runtime in tools/pole/web/pole-runtime.mjs.

The manifest is the interface#

The browser runtime learns all of it from the manifest: entry symbols, parameter ranges, state size and seeds, per-node state offsets, externals, handlers, event routes and buffer offsets.

Nothing on the browser side parses the C header, and nothing should: a runtime that parsed C would break the day the header's formatting changed.

What it needs to build#

wasi-sdk, for wasm-ld and the wasm32 libm.

Two traps that cost real time:

wasi-libc merges libm into libc.a. Its libm.a is an empty stub, so linking the file whose name says libm fails with undefined symbol: expf.
Do not install Homebrew's lld for wasm-ld. It upgrades Homebrew's LLVM, which breaks Pole's version pin for everything on the machine. wasi-sdk carries its own and touches nothing.

How close is it to native?#

24 of 29 examples render bit-identically between the JIT and the browser runtime — see the C header for the five that do not and why.

What it cannot do yet#

Sample-accurate event timing. Events are applied at block boundaries, so a note lands within about 3 ms of where it was asked for rather than on the frame it was stamped at.
Graphs with feedback, which are rendered node by node rather than fused.
Show what is happening inside a patch. The scopes here analyse what comes out; the IDE's displays are fed by telemetry ports declared in the patch.