MVC1 CROSS FEVER — FOUR-PLAYER V2.2 PREVIEW Four players in arcade Marvel vs. Capcom: ports 1 and 3 against ports 2 and 4, on one PC or online through RetroArch's netplay. It is separate from DHC and from XMvsSF 3v3 + DHC. WHAT V2.2 CHANGES - Online play works. v2.1's core named itself with 35 characters; RetroArch sends a core's name to the other players in 32 bytes, so every player who joined was refused as "a different core". The v2.2 core is named FBNeo (MVC1 Cross Fever 4P). - The core comes with its .info file, and PLAY.cmd (Windows) or play.py (macOS/Linux) installs both into RetroArch's own cores and info folders. RetroArch's Netplay host list only matches a room to an installed core that has an .info file. - PLAY.cmd finds RetroArch by itself in the usual folders and remembers it. - For online play it turns on RetroArch's relay server and the public room list, and asks your name once, in RetroArch's own settings (retroarch.cfg; the first time it keeps a copy as retroarch.cfg.before-cross-fever). v2.1 passed these as extra settings for one launch only; RetroArch drops those when a host starts or a player joins. - The game patch is the same as v2.1's (and v2's game). An mvsc4p.zip you already built with v2.1 is the same game; you can copy it into this package's output folder with its .receipt.json file, or build it again. WHAT YOU NEED - Your clean MVC1 Europe 980123 set, mvsc.zip, with its original mvsc.key. If you play MvC1 on Fightcade, it is in Fightcade's ROMs folder: Fightcade\emulator\fbneo\ROMs\mvsc.zip. Your file is only read. - RetroArch, free from https://www.retroarch.com. It is not included. Everyone in an online game should use the same RetroArch version. - Windows 10/11 x64, macOS 26+ on Apple silicon, or Linux x64. INSTALL (ONE TIME) 1. Extract this package into a new folder you can write to. 2. Windows: drag your mvsc.zip onto BUILD.cmd. No Python is needed. macOS/Linux: python3 install.py /path/to/your/mvsc.zip This makes output/mvsc4p.zip and its receipt. It refuses to overwrite an existing output; extract the package again to build again. Python needs a disk with hard links (APFS, ext4, NTFS), not exFAT/FAT or a network share. 3. Windows: double-click PLAY.cmd. macOS/Linux: python3 play.py If Windows says it protected your PC, choose More info, then Run anyway. The first time it asks your name for online play. It installs the core into RetroArch and starts the game; RetroArch's title bar names the core: FBNeo (MVC1 Cross Fever 4P). Use PLAY.cmd (or play.py) every time, with RetroArch closed. CONTROLLERS Online, each player sets up only their own controller, as Port 1: Settings > Input > RetroPad Binds > Port 1 Controls. On one PC, give four controllers different Device Index values for ports 1-4. Quick Menu > Controls shows this game's buttons. Default RetroPad buttons: Y = LP X = MP L = HP B = LK A = MK R = HK Start and Select/Coin do nothing in this game: it runs in free play. HP+HK join (at the title or character select), and tag QCF+HP+HK Team Hyper QCB+HP+HK Duo (at least two bars) P1 and P2 choose the first fighters; P3 and P4 choose the partners. Each fighter stays on its own player's controller. PLAY ONLINE WITH FOUR PEOPLE Everyone builds their own mvsc4p.zip from their own clean mvsc.zip and starts the game with PLAY.cmd (or play.py). In RetroArch, F1 opens and closes the menu and Backspace goes back. To change your name later: Settings > User > Username. Host (player 1): Main Menu > Netplay > Host. "Use Relay Server" is already on: pick the Relay Server Location closest to all four players, then Start Netplay Host. A Server Password is optional; the others then type it to join. If Windows asks whether RetroArch may use the network, allow it. Everyone else: Main Menu > Netplay > Refresh Netplay Host List, then pick the host's room, "Internet (Relay): ". RetroArch says "You have joined as player N". The first to join is player 2, the second player 3, the third player 4. Teams: player 1 and player 3 against player 2 and player 4. Then everyone presses HP+HK at the title. If the room is not listed, refresh again after a few seconds, and check that the host's Use Relay Server is on. If picking the room does nothing, that player's RetroArch was not started with PLAY.cmd: quit RetroArch and start it again with PLAY.cmd. "A netplay peer is running a different core" means someone is still on v2.1 or a stock core. WHAT WAS TESTED - RetroArch 1.22.2 (built for Linux) with this package's Linux core and play.py: four RetroArch users on one machine, each with their own package, game build and settings. The host used Netplay > Host > Start Netplay Host through a relay; the three others joined from Netplay > Refresh Netplay Host List and became players 2, 3 and 4. In the fight each player's controls moved only their own fighter, also after tags (3P and 4P markers). The lobby and relay ran locally (a stand-in for RetroArch's lobby server, and libretro's netplay-tunnel-server), not on the public servers. - v2.1's core in the same test: every joining player was refused. - The Windows DLL in a small libretro host under Wine 9: the same 3,000 frames of a scripted four-player start as the Linux core, picture for picture. - PLAY.cmd's script: 20 cases under PowerShell 7 (on Linux): finding RetroArch and its folders, the settings file, the name, and refusals. - Not tested: Windows itself (PowerShell 5.1, RetroArch for Windows), macOS, the public lobby and relay servers, internet latency, four physical controllers, real hardware. Please report what you find. Details: TEST_RESULTS.json. REPORT A RESULT Include the package version, operating system, RetroArch version, the player numbers RetroArch gave, and the exact message or action that failed. SOURCE AND CREDITS The core is FinalBurn Neo for libretro at commit aceeebed9e7edc8a28652365a064baee9a16e274 with this project's mvsc4p driver, its four-controller declaration (shared with XCOTA TAG) and the core name. FBNeo's license and the corresponding source download accompany this package. No game ROM, decryption key or save state is distributed. RetroArch guides: https://docs.libretro.com/guides/netplay-getting-started/ https://docs.libretro.com/guides/input-and-controls/