nbnet provides two different WebRTC drivers, WASM and native. The WASM driver has to be compiled with emscripten and can be used to target web browsers or Node JS. The native driver can be compiled as a native application.
If you want to build an online game that can run in a web browser, I recommend using the WASM driver for the client and the native driver for the server.
Please refer to the echo example for a concrete demonstration of how to use these two drivers.
If you want to target WASM, you'll need to compile your code with emscripten. You can either use the emcc command directly or use CMake (refer to the examples to see how to set it up).
The following emscripten options are mandatory and must always be added to your compilation command line or CMake script.
emscripten does not provide a C API for WebRTC, only a JS one. nbnet provides a wrapper around it so you don't have to write any JS code (oof!). All you have to do is compile with:
--js-library "net_drivers/webrtc/js/api.js"
The nbnet JS API uses a bunch of asynchronous functions that you'll need to let emscripten know about:
-s ASYNCIFY
-s ASYNCIFY_IMPORTS="[\"__js_game_client_start\", \"__js_game_client_close\", \"__js_game_server_start\\"]"
nbnet network conditions simulation runs in a separate thread so if you want to use it you'll need to compile with:
-s USE_PTHREADS=1
If you want to run your code in a web browser, you'll also need to provide a shell file:
--shell-file <PATH TO YOUR SHELL FILE>
To learn more about shell files: https://emscripten.org/docs/tools_reference/emcc.html
You can also look at the shell.html from the raylib example.
For more information: https://emscripten.org/docs/tools_reference/emcc.html
The Native WebRTC driver depends on libdatachannel. Please follow the building instructions in the library repository.
If you decide to go with WASM for your server, you'll need to run it in a NodeJS server. You can get NodeJS from here.
Once it's installed, you'll need to create a package.json file. Check out the echo and raylib examples to see what this file should look like. (For more information: https://docs.npmjs.com/creating-a-package-json-file)
To run your server, you need to install the required NodeJS packages by running:
npm install
from the directory containing your package.json file.
Then to run your server:
node server.js
server.js is the JS file generated by emscripten.
Unless your client is a non-graphical application, you'll probably want your client to run in a web browser.
With the correct options emscripten will output an HTML file, from here, all you need to do is run an HTTP server that serves this file and open it in your web browser.
For testing purposes, I recommend using Python SimpleHTTPServer.
Just run:
python -m SimpleHTTPServer 8000
in the directory containing your HTML file; then, open http://localhost:8000 in your web browser and open your client HTML file.
One significant difference between running JS code in a web browser compared to running it in NodeJS is that you cannot use the NodeJS packaging system. nbnet's WebRTC code relies on NodeJS packages, so, for nbnet to run in a web browser we need to "bundle" those packages into something that can be used by a web browser.
I recommend using browserify.
To bundle packages with browserify, you need to first install the required NodeJS packages by running:
npm install
from the directory containing the same package.json file used by your server.
Then you can run:
browserify net_drivers/webrtc/js/nbnet.js -o nbnet_bundle.js
and include the generated nbnet_bundle.js script in your HTML shell file:
<script src="nbnet_bundle.js"></script>
See the raylib example to see how you can integrate this operation into a CMake script.