Getting Started - GingerTeaOrg/Metrostroi-Coding-Wiki GitHub Wiki

To begin, it is best to start off with a sample script, to save you the trouble of having to establish the basic structure. I recommend taking the script for the Tatra tram, as it already includes all files and references necessary for a basic, movable train. As a basic requisit, I assume you already have downloaded and extracted the Metrostroi script addon.

Navigate to your Garry's Mod addon folder.

Create a new folder by whatever name you choose. This is going to be your work folder into which you copy all the files we're going to mention next.

Within your work folder, create a lua folder. And within that, create entities and metrostroi/systems.

The scripts can be found in the extracted Metrostroi addon folder under lua/entities/gmod_subway_tatra_t3.

Copy them into a new folder with the naming pattern gmod_subway_ followed by whatever name you desire and make sure the folder you create sits in [workfolder]/lua/entities. NOTE: Unless you're planning to write a hook that defines your train as a Metrostroi train, the folder name absolutely needs to start with gmod_subway_, as it defines the entity class name of your train. Metrostroi scans all possible entity classes on starting the game, and flags every entity with that prefix as a metro train. Without that flag, your train would not be reported by Metrostroi's pathing system, making it invisible to any built-in Metrostroi signalling.

We also need to go and fetch its systems file. From your metrostroi copy, go to lua/metrostroi/systems/ and copy sys_tatra_systems.lua into the same folder you're taking it from. Rename it sys_ followed by whatever name you choose.

Open the file in your preferred text editor (do NOT torture yourself by using a standard editor like Notepad, use a better one like Notepad++ or even VSCodium) and look for the line containing DefineSystem and change the string in the parentheses to anything you wish. It's probably best to make it relevant to your train though.

Next, to keep your train from erroring upon spawn, you need to go to the train script folder that you've created. Open shared.lua and look for a line containing LoadSystem. Replace the String within the parentheses with whatever you named your system in the line containing DefineSystem.

While we're in this file, feel free to change the name of your entity. You have to add a few instructions at the top in order to make that work. See here for a listing of those. You may change the category, author name, entity name, etc to your liking.

If that's all done, you should now see your new entity in the entity browser under the category you gave it. Huzzah!