MW2WEB

Call of Duty: Modern Warfare 2 (2009) multiplayer in a browser tab. MW2WEB is a fork of IW4L, an open-source MW2 runtime written in Rust with Bevy, compiled to WebAssembly and drawn with WebGPU. The live site is play.mw2web.com; updates are posted on X @mw2web_.

This repository is code only. It contains no game files and no game art. To run it you need your own installed copy of MW2 Multiplayer; the engine reads that installation without patching or replacing its files.

What it adds to IW4L

Area	What
Browser build	The engine compiled to wasm32 with threads (Web Workers sharing memory) for Chrome and Edge, and a single-threaded build for Firefox. Rendering goes through WebGPU.
Threads	The game simulation runs on its own thread next to the renderer (pipelined), with worker pools for loading, render setup, skinning, effects and audio decode.
File streaming	Game files stream from the host in small blocks and are kept in the browser's private file system. Each load records which blocks a map reads, so the next player's download is prefetched in bulk.
Lobby	A web lobby (web/index.html) over the relay server in crates/iw4l-master (lan mode): a match list, hosting with passwords and map rotation, Create a Class, and accounts.
Counter-Strike maps	crates/source_map compiles Hammer .vmf maps into the engine's world, collision, lightmaps and entities; crates/cs2_textures pulls their textures, props and radar pictures from a Counter-Strike 2 install.
Performance	Frame pacing, automatic render resolution, capped pipeline compilation while loading, and many render and simulation optimizations. PERFORMANCE.md lists each one with its measured effect, and what is still left to do.

Build

You need Rust through rustup (the toolchain is pinned in rust-toolchain.toml), GNU Make, and your own MW2 Multiplayer install. See IW4L's build dependencies for the native toolchain.

Native, as upstream:

cp .env.example .env
# Edit .env: set IW4L_GAMES to the folder containing your game installations.
make map mp_boneyard CMDS='wait world; spawn 0; force_match_start; bot add 3'

Browser (also needs the wasm32-unknown-unknown target, clang for the C crates, and wasm-bindgen-cli matching Cargo.lock):

bash scripts/web/build.sh            # single-threaded bundle -> web/pkg
bash scripts/web/build-threads.sh    # threaded bundle (nightly + rust-src) -> web/pkg-exp

Run it locally: the relay serves the page, the lobby and your own game folder to your browser on this machine.

cargo run --release -p iw4l-master -- lan --bind 127.0.0.1:8444 --http 127.0.0.1:8481 \
  --web web --games "/path/to/Call of Duty Modern Warfare 2"
# then open http://127.0.0.1:8481/?lan=1

The page expects fonts and a few images under web/assets/, which are not in this repository; web/assets/README.md lists what goes there.

scripts/web/pack.sh packs a build for serving, and scripts/web/deploy-exp.sh uploads it to a server named in scripts/web/deploy.env (see scripts/web/deploy.env.example).

Layout

• crates/: the engine (asset readers, simulation, rendering, audio, networking) and the tools around it.
• web/: the lobby page, the docs page and the workers that host the engine.
• vendor/wgpu: wgpu with a deferred (createRenderPipelineAsync) pipeline path.
• scripts/web/: browser build, packing and deploy scripts.
• docs/: IW4L's engine documentation.

Acknowledgements and license

MW2WEB is built on IW4L by vladtrc and everyone who contributed to it, including ju1cedr1nker and silvernote03, who QA-tested weapons, maps, attachments and other gameplay features.

OpenAssetTools and its iw4x-x64 fork informed asset layouts; IW4x informed asset and protocol behavior; KisakCOD informed engine structure. Ghidra was used to inspect the original binaries. The Counter-Strike map layouts come from ReagentX/decompiled-csgo-maps.

The source is licensed under Apache 2.0. Preserve the attribution in NOTICE and the bundled font licence texts when redistributing. Original game assets and trademarks belong to their owners (Activision and Infinity Ward for Modern Warfare 2, Valve for Counter-Strike). MW2WEB is unaffiliated with them.