WASM Experiments

Playing around with CPP -> WASM

How to get the smallest useful WASM bundle?

The goal here is to build the most lightweight .wasm module possible that does something useful. Emscripten while great, will add a lot of cruft to your wasm bundle if you attempt to use any sort of standard library(see https://github.com/WebAssembly/binaryen/issues/670). It will also generate a 2k+ line .js bundle to allow you to use things like printf from within your wasm code.

Instead you may use ONLY_MY_CODE=1 while compiling C/++ to wasm to avoid all that... But of course this gives up the ability to use anything useful in your C code. Or does it?

Here we experiment with building a purely number crunching wasm bundle, which will simulate a very basic physics engine. Import it into a Browser, run it inside a webworker and hook into some simple WebGL animations.

So far only a very simple counter example build and runs on Chrome 56. Tests on Chrome Canary and Firefox nightly fail as the binary wasm versions supported by these browsers are above that generated by emscripten.

Install

• Install emscripten, binaryen.
• npm install
• npm run build-object

There is a custom dep on a wasm utils repo of mine. It's needed for stack, logger and memory operations from wasm code. https://github.com/ballercat/wasm-utils

Run

• webpack-dev-server

The current working demo allocates a new object on the heap and is able to print out a custom struct from the allocated object into the JS console.

TODO

• Update wasm-utils. Better heap, better export managment
• Update build process, add makefile + sh script.