Your M.U.G.E.N game, unchanged, on a modern 64-bit engine.
Drop OMugen.exe into any MUGEN 1.1 folder and play: same characters, stages, screenpack and controls. Nothing to convert.

Why OMugen

• One file, any MUGEN game. Copy OMugen.exe next to data, chars and stages. The engine's own files live inside the exe; OMugen never changes the game's files and only adds a save folder.
• Your controls, as they are. Keys and pad buttons come from the game's mugen.cfg, with MUGEN 1.1's exact codes. Changes made in Options are written back to it.
• Plug-and-play controllers for up to 4 players. DualShock 4, DualSense and Xbox pads, over USB or Bluetooth, no DS4Windows needed. Players get the pads that send input, the light bar takes the player's color, and every menu shows who is selecting.
• Fast with huge rosters. A 1,580-character game reaches the menu in about 2 seconds.
• Smooth on 120-240 Hz monitors. The game still runs at 60 ticks per second and plays exactly the same; characters, camera and stages are drawn smoothly in between.
• Online and LAN play, delay-based or with rollback netcode.
• Nothing breaks the game. If a screenpack or lifebars fail to load, OMugen's own take over and say so. OMugen.exe -doctor checks every character and stage and writes a report.
• Make your own game. OMugen.exe -newgame "My Game" creates a playable game: a full template fighter, a stage, menus and lifebars, all in standard MUGEN formats.
• On your phone too. OMugen for Android plays the same game folders, with an on-screen DualShock 4 or Bluetooth controllers.

OMugen and MUGEN 1.1

	M.U.G.E.N 1.1	OMugen
Runs on	32-bit, Windows	64-bit, Windows and Android (Linux builds: early)
Your game folder	as is	as is (OMugen adds only save)
Controls	mugen.cfg	the same mugen.cfg and codes, plus pads assigned automatically for up to 4 players
Above 60 fps	the game itself speeds up	up to 240 fps or the monitor's rate, same gameplay (checked tick by tick)
Online	no	online and LAN (delay-based or rollback netcode)
A broken screenpack or lifebars	error	OMugen's built-in ones take over
Checking a big game	one character at a time	-doctor: a report on every character and stage
Starting a new game	from an empty folder	-newgame: a playable template

Getting started

1. Download OMugen.exe from Releases (or build it).
2. Copy it into your MUGEN 1.1 game folder, next to mugen.exe.
3. Run it.

Started outside a game folder, OMugen says where it belongs and offers to create a new game of your own there instead.

The first start unpacks the engine files once to %LOCALAPPDATA%\OMugen\engine\, never into the game folder. Settings, logs, replays and reports go to the game's save folder. Files in the game folder always win over OMugen's built-in copies.

On Android

1. Download OMugen-<version>-android.apk from Releases and install it (Android asks you to allow installing apps from your browser or file manager once). Android 8 or newer, on 64-bit phones with OpenGL ES 3.2 (most phones since 2017).
2. Copy your MUGEN game folder (the one with data, chars and stages) into a folder named OMugen in your phone's internal storage. Too big for the phone? Leave it on a USB drive or SD card (Android 11+): OMugen finds games in an OMugen folder there or at the top of the drive, and Add a game folder picks any other folder. Games are played where they are, nothing is copied.
3. Open OMugen, tap Allow file access, then your game.

The settings under the game list choose the on-screen controller (a DualShock 4 drawn over the game, with your pad layout) or Bluetooth controllers only, and the frame rate: 60 fps saves battery, more is smoother on 90-144 Hz screens. The Back button works as Escape (the pause menu in a fight, back in menus). If a game closes on an error, the app shows what went wrong the next time it opens, and can share it.

FAQ

Windows says the app is unrecognized. OMugen.exe isn't code-signed yet: click More info, then Run anyway.

Where are my settings, saves and logs? In the game's save folder: config.ini, replays, stats, and save/logs (crash logs, controllers.txt). OMugen's own files (its engine files, your pad layouts) are in %LOCALAPPDATA%\OMugen, never in a game folder.

The window is too big, or blurry. OMugen draws each frame at the window's own resolution, in your screen's real pixels (also with Windows' display scaling, 125% or 150%), and shrinks a window that wouldn't fit the screen. Alt+Enter switches to fullscreen. Options > Video Settings > Resolution sets the window's size and shape; Native Resolution off draws at that resolution instead and scales it (lighter on old PCs).

My controller does the wrong moves. A game's mugen.cfg is set up for one kind of controller. When it doesn't fit yours, OMugen uses your own layout for that kind of controller, or the standard one (see Features); save/logs/controllers.txt says which. Options > Input Settings changes it. Which button does a special or an ultimate is up to each character: many need a full power bar.

The game's menus look different. Its screenpack failed to load and OMugen's took over; the notice on the title screen says why. Options > Video Settings > OMugen Screenpack switches between them.

Android: the new version won't install over the old one. v0.1.3 was signed with a test key: uninstall it once. Later versions install over each other.

Android: my USB drive or SD card isn't listed. It needs Android 11 or newer and a format the phone reads (FAT32 or exFAT; most phones can't read NTFS). Tap Refresh, or Add a game folder to pick the game's folder.

Android: the phone gets warm. HD resolution (Options > Video Settings) and 60 fps run the coolest.

A game crashes or misbehaves. Please open an issue with the log: from save/logs on a PC; on a phone, the error report the app shows (or Send the last game's log in its settings).

Features

• Controls come straight from mugen.cfg: keyboard keys (SDL 1.2 key codes) and joystick codes decoded from MUGEN 1.1 itself, so every button matches. Options > Input Settings shows and edits them in MUGEN's own notation (A-17...). The pad's Start/Options button opens the pause menu.
• Controllers are read through SDL and laid out the way MUGEN numbers them, so mugen.cfg codes keep their meaning (OMUGEN_JOY=winmm reads them exactly like MUGEN). Players get the controllers that actually send input, in the order they are first pressed; a player keeps the pad their own codes name. Pads that send nothing, and copies that mirror another pad (DS4Windows), are skipped. Players without joystick codes of their own play with player 1's layout. Options > Input Settings > Reassign Controllers hands them out again. save/logs/controllers.txt lists what OMugen sees.
• Your pad layout follows you. A game's joystick codes are numbered for the controller they were set up on; on another kind they can land on its triggers (a menu that scrolls by itself). Then OMugen uses your own layout for that kind of controller: the first one you played with, or the last one saved in Options (kept in %LOCALAPPDATA%\OMugen\pad-layouts.ini), or else the standard layout: left stick and D-pad to move, A B C on Square Triangle Circle, X Y Z on Cross R1 R2, MUGEN's Start (energy charge in many games) on L1, the pause menu on Options (Xbox pads by position).
• Controller indicator: P1-P4 tags in the corner show who has a controller, a notice appears when one joins, and the highlighted menu item shows who is selecting.
• Sharp at any size. Every frame is drawn at the window's own resolution and reaches the screen 1:1: resize the window or go fullscreen and it stays sharp (MUGEN stretches a fixed resolution). It also respects Windows' display scaling and keeps windows on the screen.
• Screenpack, resolution, window and fullscreen come from mugen.cfg; changes made in Options are saved back to it (a backup goes to save/backups first).
• The game's own rules: the first start takes life, round time, difficulty, game speed, team, volume, arcade AI and stage-fit settings from mugen.cfg, so the game plays as it does in MUGEN. Changes made later in Options are saved to both.
• OMugen screenpack: Options > Video Settings > OMugen Screenpack (or -omugenui). A 1920x1080 interface that uses the game's characters, stages, lifebars, sounds and music, sizes the select grid to the roster and fits portraits of any size (cut like the game's own screenpack cuts them, for games that draw both sides' portraits in one picture).
• OMugen lifebars: used by new games and by any game whose lifebars fail to load. They bring the standard hit sparks and hit sounds MUGEN characters call by number.
• OMugen Doctor: OMugen.exe -doctor loads every character and stage in select.def the way a match does and writes save/doctor/report.html (errors, crashes, missing sprites, warnings). Options: -doctor chars|stages, -doctorlimit N, -doctorfilter name1,name2.
• Frame rate: Options > Video Settings > Frame Rate: 60 (default, like MUGEN), 120, 144, 165, 240 or Monitor.
• Glow: Options > Video Settings > Glow Effects (off by default, like MUGEN).
• Loading: the roster's files are read in parallel and the sprite file headers are cached in save/cache, so big games start in seconds, even right after a reboot.

Making your own game

OMugen.exe -newgame "My Game" creates a folder with everything a new fighting game needs, ready to play and to change:

• Proto, a complete template fighter (an armored android martial artist): 6 palettes, normals on the ground and in the air, a projectile, a super move, a move list for the pause menu, and every standard animation the common states use, with collision boxes.
• Proto Arena, a rooftop dojo at night above a neon city, in six parallax layers (1280x720).
• Editable copies of the OMugen screenpack and lifebars, data/select.def, and the game's name as its window title.
• GUIDE.txt: how the files fit together and how to make characters, stages and menus.

Everything uses the MUGEN 1.1 formats, so MUGEN tools and tutorials apply.

Made from code

Every image and sound OMugen ships is generated by its own tools, with no third-party art:

• tools/screenpackgen: the OMugen screenpack.
• tools/lifebarsgen: the lifebars, hit sparks, common sounds, engine effects and move list icons.
• tools/templategen: Proto and Proto Arena.
• tools/logogen: the logo and icons.

Other tools: tools/mugenjoytest shows the MUGEN joystick code of every button you press; tools/make_testgame.ps1 builds a zero-copy test folder from a MUGEN game; and -inputscript file plays scripted input and takes screenshots, for automated tests.

Building

See BUILDING.md. In short: on Windows (MSYS2 MINGW64) or Linux, run build/omugen_build.sh (Win64, Linux or, on Linux, Android). GitHub Actions builds all three; pushing a version tag publishes them as a Release.

Credits

OMugen's engine core comes from Ikemen GO by the Ikemen GO team and contributors (itself a rewrite of Suehiro's I.K.E.M.E.N); OMugen builds its MUGEN drop-in compatibility, interface, tools and art on top of it. M.U.G.E.N is by Elecbyte; OMugen is not affiliated with Elecbyte and contains none of its code.

License

MIT License: see LICENCE.txt, which keeps the copyright notices of everyone whose code OMugen builds on, as the license requires. Bundled third-party components keep their own licenses (Open Sans: Apache 2.0; FFmpeg: LGPL v2.1, dynamically linked, rebuildable with build/build.sh), listed in the same file.