deliriumpulse/cardshopcoop

CardShopCoop is a mod for the game TCG Card Shop Simulator that adds true co-op multiplayer. Normally the game is single player, so this project lets two people run the same card shop together, sharing money, experience, the card collection, prices, stock, and customers, either over Steam or a local network. One player hosts the game and the other joins as a client. The host's simulation is treated as the single source of truth, while the joining player can still do real work: they can serve customers at the register, handle trade-ins, restock shelves, set prices, order new stock and furniture, hire staff, pay bills, and buy licenses, all of which is reflected back into the host's actual game. Customers and workers appear as smoothly animated characters for both players, and the day and night cycle and lighting stay in sync between them. Anything the joining player does happens in a temporary save slot, so their own save file is never touched or overwritten. The mod is built to work alongside other content mods for the game, such as PTCGO and Enhanced Prefab Loader. When two players join together, it checks that both are running the same plugin version and the same set of content mods, and gives a readable explanation if something does not match, rather than failing silently. Technically, it is a BepInEx plugin written in C# for Unity, and it uses two kinds of network communication: a reliable channel for important state changes and a faster, less strict channel for player and customer movement. The project's README also documents several tricky bugs the developers ran into while building this, which are recorded directly in the code. This is aimed at players of TCG Card Shop Simulator who want to run a shop with a friend, and at modders interested in how Unity game co-op mods are built. It is released under the MIT license, and does not redistribute any of the original game's files.