Repo ↗ · Source README ↗ · Markdown & license bundle

Image reference (original game): Call of Duty: Modern Warfare 2 · original-game artwork, provided by IGDB. Image rights remain with their respective owners. This illustrates the referenced original game, not the actual visuals of this rewrite or mod.

Source maintainer: ixbh · Revision: d0b849e2f8a8 · Catalogued: 2026-10-12

Source license: Apache-2.0 · LICENSE · Article: Source README (format adapted)

The source README follows, with formatting adapted for this site and images replaced by source links. Feature, completion and testing claims belong to its authors and have not been independently playtested here. The Traditional Chinese translation was prepared with AI assistance.

IW4L + Apex (fork)

This is a fork of vladtrc/iw4L (branch
apex-movement) that replaces MW2’s movement and guns with Apex Legends
movement and weapon behaviour from
ApexRuntime: measured against
offline R5Flowstate and re-implemented from scratch. Optional Apex models,
sounds and HUD come from your own personal export; none are in this repo.

Install: clone this repo next to ApexRuntime and follow
ApexRuntime’s INSTALL.md.
Quick start once built: . un-apex.ps1.

Changes from upstream live mostly in crates/sim/src/apex*.rs,
crates/render_anim/src/anim/apex_*.rs, crates/render_gpu/src/drawsurf/apex_*,
crates/audio/src/apex_weapon_sfx.rs, crates/console/src/apex_*.rs,
crates/asset_game/src/apex_weapons.rs and run-apex.ps1. Not affiliated
with the upstream IW4L authors, Activision, EA or Respawn.

The original IW4L README follows.

IW4L

IW4L is an open-source runtime for Call of Duty: Modern Warfare 2 (2009), written in
Rust with Bevy. Point it at a copy of MW2 you already own and it
loads that installation’s maps, models, textures and weapons into its own engine. You
can try implemented movement and combat on multiplayer maps, then inspect or change how
those systems work.

README image：Bomb planting in IW4L
README image：Tanker explosion in IW4L

What you can try

Explore maps, fight bots, and record and replay demos. Gameplay remains incomplete;
expect missing behavior, bugs and desyncs. The asset readers also cover MW3 and Black
Ops.

Build from source. APIs, configuration, caches and the wire protocol change between
commits; multiplayer peers must run the same commit.

Build and run

Install Rust through rustup and GNU Make. Build dependencies cover
Linux’s C/C++ toolchain and system libraries, and macOS’s Xcode command line tools.
Windows instructions cover building and arranging a portable folder.

You need your own installed MW2 Multiplayer data, including common_mp.ff. IW4L
distributes no game assets and reads installations without patching or replacing their
files. Caches, demos and logs go under iw4l-artifacts/; Linux settings use a separate
configuration directory described in the run guide.

From the repository root:

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'

This builds the optimized play profile and starts a local match with three bots.
force_match_start skips the warmup that otherwise freezes movement.

Inside the engine

Area Implementation
Assets Native FastFile readers convert game data into a shared intermediate representation.
Shaders Retail Direct3D 9 Shader Model 3 bytecode is translated to WGSL.
Rendering World geometry, models and effects feed one sorted draw-surface list.
Simulation Server authority, client prediction and replay share one simulation step over explicit Bevy ECS state.
Networking Custom UDP traffic; a QUIC master provides browsing and relaying. The host simulates the match.

Where to go next

This whole project is written by an LLM.

Acknowledgements and license

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.

IW4L’s source is licensed under Apache 2.0. Preserve required attribution and
bundled font license texts when redistributing; see NOTICE. Original game
assets and trademarks belong to their owners. IW4L is unaffiliated with them.

License and provenance

The README and its translation retain Apache-2.0 terms. Changes comprise translation, links and formatting. Editable Markdown, the original README, LICENSE and NOTICE files are included in the linked bundle. This grants no rights to the original games, their assets or trademarks.

LICENSE

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IW4L

Copyright 2026 vladtrc

IW4L was originally developed by vladtrc.
https://github.com/vladtrc/iw4L

IW4L is licensed under the Apache License, Version 2.0; see LICENSE.

--------------------------------------------------------------------------------
Third-party material bundled with this repository
--------------------------------------------------------------------------------

Both fonts below are compiled into the IW4L binary with `include_bytes!`, so
they are redistributed with every build. Any archive that ships an IW4L binary
ships these two licence texts with it.

Oxanium (crates/ui/assets/Oxanium-Regular.ttf)
  Copyright 2019 The Oxanium Project Authors
  https://github.com/sevmeyer/oxanium
  SIL Open Font License 1.1 — full text in crates/ui/assets/OFL-Oxanium.txt

GNU FreeFont (crates/console/assets/FreeMono.otf)
  Copyright (C) 2002-2012 Free Software Foundation, Inc.
  https://www.gnu.org/software/freefont/
  GNU General Public License v3 or later, with the GNU font exception — full
  text in crates/console/assets/COPYING-FreeFont.txt. The exception is what
  makes embedding the font in an Apache-2.0 binary possible: a document or
  program that merely uses the font is not thereby covered by the GPL. The
  font itself is unmodified and remains under the GPL.

--------------------------------------------------------------------------------
Third-party source code
--------------------------------------------------------------------------------

No third-party source code is vendored in this repository, and the build links
no third-party project named below. IW4L's own dependencies are the crates
declared in Cargo.toml, under their own licences.

--------------------------------------------------------------------------------
References consulted during development
--------------------------------------------------------------------------------

These projects were read while working out how the original games behave. They
are named here because the reading happened, not because anything of theirs is
distributed: none of them is vendored, linked, bundled or otherwise shipped.

OpenAssetTools — https://github.com/Laupetin/OpenAssetTools
  Open-source modding tools for older Call of Duty games. Its asset-structure
  headers document the on-disk layouts IW4L reads. Licensed under GPLv3.

oat (iw4x-x64 fork of OpenAssetTools) — https://github.com/iw4x-x64/oat
  The x64 fork, at revision 3a7442dee5ce040cfdb8da23fdb9fb525b5f743e, is the
  tree whose IW4MS headers were read for the 64-bit FastFile layouts.
  Licensed under GPLv3, like its upstream. No file in this repository is
  compiled against, generated from or distributed with those headers.

IW4x — https://github.com/iw4x/iw4x-client
  A custom client for Call of Duty: Modern Warfare 2 (2009), with dedicated
  servers, security fixes and modding support. Read as a cross-reference for
  asset and protocol behaviour. Licensed under GPLv3.

KisakCOD — https://github.com/SwagSoftware/KisakCOD
  A Call of Duty 4 open-source reimplementation. Read as a cross-reference for
  engine structure. IW4L targets IW4, so this is a neighbouring generation of
  the same engine family, not the same codebase.

Ghidra — https://github.com/NationalSecurityAgency/ghidra
  The software reverse engineering framework the original game binaries were
  read with. A development tool: none of it, and none of its output, is
  committed here or distributed with IW4L. Licensed under Apache 2.0.

--------------------------------------------------------------------------------
Game content
--------------------------------------------------------------------------------

No Call of Duty game data is contained in this repository or in any IW4L
release archive. IW4L reads game data from a copy of the game the user already
owns and has installed. Call of Duty, Modern Warfare, Black Ops, related
trademarks and all original game assets belong to their respective owners.
IW4L is not affiliated with, endorsed by or supported by them.

This fork (apex-movement branch) modifies IW4L to run Apex Legends-style
movement and weapons from ApexRuntime; modified and added files are listed
in the git history and README.