Minecraft Forge API high level questions and clarification

[iirubixii]

question, new to PC Minecraft but not Java (i don't get to do any web app stuff at work though). I'd like to ask some clarifying questions about how MC and mods run at a high level view before diving in as I haven't modded anything before. I am looking to start playing/modding since I want a new project to work on here and there. Thanks to anyone who can help answer my questions / correct my understanding of the backend.

After reading docs, it seems that servers are just fat jars distributed from Mojang. Mods / plugins are distributed from users as jars. You can install Minecraft Forge using their installer. Does the MC Forge installer just give you a repackaged Mojang server jar that includes their API? 

After MC Forge is installed, you can include users jars into their mod directory that is now on your server, then you need to have the JRE restart the app to load the new dependencies. From what I can see, it seems like it is working like a glorified Maven build tool behind the scenes, as it is seems to be in charge of managing all the dependencies gracefully.

How are users creating their mods from scratch, are users decompiling mojangs servers fat jars and starting there for their mods? As in, if I wanted to create a mod that introduced a new custom mob, wouldn't I need to somehow look at how actual mobs are being built by decompiling then make a similar model and repackage the jar and rerun the app? 

If I didn't want to make it from scratch, I use MC Forge MDK and an API like https://maven.thiakil.com/forge-1.12-javadoc/net/minecraft/item/Item.html to create new item as an asset, register it, and upload jar to the MC Forge directory in the server and it should handle it all nicely between client/server, is that right? I am still going through the docs and just taking a browse before I buy the game and try to setup their hello world program they have for creating your first mod.

[warjort]

Quote

After reading docs, it seems that servers are just fat jars distributed from Mojang. Mods / plugins are distributed from users as jars. You can install Minecraft Forge using their installer. Does the MC Forge installer just give you a repackaged Mojang server jar that includes their API? 

It downloads the mojang jar(s) at installation and modifies them. You still need a minecraft license.

 

How are users creating their mods from scratch, are users decompiling mojangs servers fat jars and starting there for their mods? As in, if I wanted to create a mod that introduced a new custom mob, wouldn't I need to somehow look at how actual mobs are being built by decompiling then make a similar model and repackage the jar and rerun the app? 

The mdk is an example mod. You actually just need ForgeGradle that the mdk uses. Mods are gradle projects.

https://docs.minecraftforge.net/en/latest/gettingstarted/

 

Forge for 1.12 is old and no longer supported. Use 1.18.2 if you are getting started. 

[Ugdhar]

2 hours ago, iirubixii said:

Does the MC Forge installer just give you a repackaged Mojang server jar that includes their API?

Sort of, but they do not distribute the MC code, the installer decompiles/deobfuscates/patches/reobf/recompiles the MC code.

2 hours ago, iirubixii said:

How are users creating their mods from scratch, are users decompiling mojangs servers fat jars and starting there for their mods?

More or less, the problem here is that historically when it's done this way, mods aren't as likely to be compatible with one another as using an API like Forge.

2 hours ago, iirubixii said:

If I didn't want to make it from scratch, I use MC Forge MDK and an API like https://maven.thiakil.com/forge-1.12-javadoc/net/minecraft/item/Item.html to create new item as an asset, register it, and upload jar to the MC Forge directory in the server and it should handle it all nicely between client/server, is that right?

As someone above mentioned, I would use a modern version, as old versions aren't supported on here (manpower, pushing to use new stuff for features/bug fixes/security/etc). Using forge would make it easier for your mod to play well with other (Forge) mods. It is still up to the developer to make sure they're not running client-side code (i.e. models/sound/textures) on a dedicated server.

https://wiki.mcjty.eu/modding/index.php?title=Main_Page might give you some useful information, especially if you're already familiar with Java. I would also suggest browsing the forge docs https://docs.minecraftforge.net/en/latest/, the getting started section will get you up and running, and it explains other things such as registries and sides.

And if you run into issues, post your code to Github as a working repo (makes it easier for people to help debug), describe your problem in a support post on here, and chances are good someone will be able to help fix it.

Edited July 17, 2022 by Ugdhar

[iirubixii]

Thanks guys.