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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: r614 · Revision: 10d36974ca0a · 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.

Mirrorwarfare

Mirror’s Edge Catalyst parkour with Call of Duty: Modern Warfare 2 (2009) guns, in a
free-for-all with bots. Mirrorwarfare is a fork of iw4L,
an open-source MW2 runtime written in Rust with Bevy. It reads both
games from installations you already own: nothing from either game is in this repository.

What’s in it

  • Catalyst movement (crates/movement_mec): sprint momentum, wallrun and wallrun
    chains, wall jumps, wallclimb and ledge grabs, the wall turn (quickturn on the wall and
    kick off), vaults, springboards, slides, coil, landing rolls and hard-landing tiers. Speeds,
    heights and timings come from Faith’s animation state graph decoded from Catalyst’s own
    data; each tuning value records where it came from.
  • MW2 combat: weapons, classes, killstreaks, the FFA game mode and bots from iw4L, with
    per-move weapon rules (hip fire during wallruns, weapon lowered while climbing, vaulting
    and rolling).
  • Faith’s third-person animations, decoded from Catalyst and retargeted onto the MW2
    body, so other players and bots run, wallrun, vault and roll like Catalyst.
  • The Parkour Playground (testbox): an 80 × 80 m arena built for the move set, with
    four chained set-pieces, a 12 m tower, 14 spawns and collision that matches what you see.
    Arenas can also be cut from Catalyst’s city with the extractor in tools/mec.
  • A deterministic autopilot and test harness: routes are generated from the arena
    geometry, an in-engine autopilot drives them from game state, repeated runs are
    tick-identical, and the harness checks movement, load, performance, bots and stability.

Catalyst movement also runs on stock MW2 maps with IW4L_MOVEMENT=mec.

Requirements

Windows, with:

  • Call of Duty: Modern Warfare 2 (2009) multiplayer, installed through Steam.
  • Mirror’s Edge Catalyst, installed through Steam or the EA app. Only needed for Catalyst’s
    third-person animations and for cutting city arenas; the Parkour Playground does not need it.
  • Rust with the MSVC build tools, uv and git.
  • About 45 GB free next to the checkout if you extract Catalyst data.

Quick start

cargo build --profile play -p launcher         # ~15 min the first time, ~2 min after
uv run scripts/mec-testbox.py                  # writes the Parkour Playground to ..\mec-arenas\testbox
.\Mirrorwarfare.cmd -Arena testbox -Bots 0     # practise on your own
.\Mirrorwarfare.cmd -Arena testbox -Bots 7     # FFA with bots

Mirrorwarfare.cmd runs this checkout’s own build (target\play\iw4l.exe, or -Exe),
finds MW2 through Steam and starts a match. -NoSound, -Spawn (skip class select),
-Menu and -List are also available. From the game’s menu: Private Match → Game Setup
→ Change Map → CATALYST, with a BOTS row in Game Setup.

Catalyst data (optional): powershell -ExecutionPolicy Bypass -File tools\mec\setup.ps1
finds Catalyst, dumps its data next to the checkout, decodes Faith’s animations into
..\mec-anims and cuts the city arenas. It is resumable; -DryRun shows the plan. Without
the animation pack the game falls back to stock MW2 animations.

Controls

Input Action
W Run; speed builds up over about 3 s (there is no sprint key)
Space Up: jump, wallrun (into a wall at an angle), wallclimb (straight at a wall), ledge grab, vault, springboard
C Down: slide while running, coil in the air, landing roll when held at touchdown
Q 180° quickturn, also on a wall during a wallclimb to kick off backwards
Mouse MW2 weapons: fire, aim (not during wallruns), reload R, melee V, grenades F / G

Type thirdperson in the console (~) to watch the body animations.

How it was built

  • Engine: iw4L provides MW2 asset loading, rendering, netcode with server authority and
    client prediction, the game scripts (GSC) and bots. Mirrorwarfare adds arena packages
    (crates/asset_mec) grafted onto a stock map for its sky, sun and materials.
  • Catalyst data: Frostbite superbundles are dumped and parsed (EBX, mesh sets,
    textures, Havok and world placement) by the Python tools in tools/mec. The ANT
    animation banks are decoded by tools/mec/antbank.py and antanim.py: the state graph,
    timing windows, root motion and clips.
  • Movement and animation: movement_mec implements Faith’s move set from the decoded
    data, runs inside the simulation step and travels in snapshots. mec_anim and
    render_anim retarget and play Catalyst clips on remote bodies.
  • Testing: tools/harness (run.py, showcase.py, determinism.py) drives the game
    with the autopilot console command. See MIRRORWARFARE.md for the
    movement details, data provenance and limitations, and docs/RUN.md for
    console commands.

This project is written almost entirely by an LLM, like the iw4L it builds on.

Known limitations

  • Third person is not fully 1:1: quickturn and the long vault use stand-ins (their clips
    use a codec that is not decoded yet), there is no hand or foot IK, and the rifle swings
    with the hand during full-body moves.
  • Catalyst’s city arenas carry base colour, normal and specular maps with baked light only;
    Catalyst’s own materials, glass and global illumination are approximated.
  • Only free-for-all is tuned. Bots find parkour routes by trial rather than planning them.
  • Online play between machines is untested; all peers must run the same build.

Mirrorwarfare is an unofficial fan project. It is not affiliated with or endorsed by
Electronic Arts, DICE, Activision or Infinity Ward. Mirror’s Edge, Call of Duty and Modern
Warfare are trademarks of their owners. You need your own copies of both games; this
repository contains no game code, assets or extracted data, and the tools read your
installations without modifying them. Catalyst data is read from installed files only; no
DRM is bypassed or modified.

Credits and license

Built on iw4L, which credits
OpenAssetTools and its iw4x-x64
fork, IW4x,
KisakCOD and
Ghidra. The Catalyst tooling builds on
Frostbite-Scripts (MIT),
FrostyToolsuite,
AssetBankPlugin and
IceBloc.

Licensed under Apache 2.0 like iw4L, except where a file states otherwise:
tools/mec/antanim.py and tools/mec/antbank.py are GPL-3.0-only
(tools/mec/LICENSE-GPL-3.0) because the animation decoder is
ported from AssetBankPlugin, and tools/mec/fbebx.py is MIT, derived from Frostbite-Scripts.
These are standalone Python tools; the game itself does not include them. Preserve required
attribution and bundled font license texts when redistributing; see NOTICE.

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.

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--------------------------------------------------------------------------------
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.

---

Mirrorwarfare additions

tools/mec/antanim.py and tools/mec/antbank.py are licensed GPL-3.0-only (see
tools/mec/LICENSE-GPL-3.0); the Dct animation decoder is a port of
marv7000/AssetBankPlugin and the AssetBank layout follows it.

tools/mec/fbebx.py is derived from Frostbite-Scripts, under the following license:

MIT License

Copyright (c) 2019 NicknineTheEagle
Portions Copyright (c) 2012-2017 Frankelstner
Portions Copyright (c) 2016 NoFaTe

Licenses for third party libraries are provided in the corresponding individual files.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.