Getting Started

Welcome to modding minecraft! We modders have a lot of control over Minecraft, but there's a lot of code and beginning can be overwhelming. But still, creating your own blocks and adding your own functionality to Minecraft is quite a liberating experience! If you don't like a facet of the game, change it! If you want more content, you can add it! These tutorials are meant to ease you into modding Minecraft by teaching basic concepts that are useful for most modders.

If you are more of a visual learner, here is a playlist of video tutorials that follow this series: http://www.youtube.com/playlist?list=PLrnh7I7rzm5zvPDCW6eGWhTVQh3BPh2bu

Goals

• To understand how to find Minecraft code you care about.
• How to create packages and classes in Eclipse
• To have and understand the boilerplate for a Minecraft mod

Prerequisites

• Have Installed your Forge development environment
• Know how to program in Java. If you don't, start learning Java. You can probably pick it up while writing mods, but don't ask for Java help in Minecraft communication channels. There are entire books on learning Java, along with online tutorials.

Credits

This tutorial is a more descriptive form of Wuppy's third and fourth tutorial. The tutorials have code, but does not explain why the code exists in a satisfactory manner. A lot of these tutorials also have analogs to Wuppy's tutorials.

For another location of source code, the master source for the Generic mod can be found on GitHub including all resources. If you cannot get the master source to work, file a bug on GitHub. If you think that the master source and the wiki source are out of sync, also file a bug.

The Generic Mod is made by Havvy, so if you have questions you want answered in real time, you might find him in the MinecraftForge IRC channel, amongst other places. He's friendly most of the time, but if you ask basic Java questions, be prepared to be told to go learn Java.

Case Matters

When you see a name, its capitalization matters. If it's all lowercase, it's all lowercase for a reason. Same for whether it starts with an Uppercase or if its is camelCase.

Most of the time, its to follow Java's capitalization standards which makes sharing readable code easier. If you throw code up in public and it doesn't follow Java's capitalization standards, I, Havvy, will look at you strangely. Mostly this happens when classes are camalCase instead of TitleCase.

Eclipse

These tutorials assume you are using Eclipse. While you don't need Eclipse, and you could use IntelliJ, NetBeans, Emacs, Vim, or something more primitive, the people who make Minecraft modding actually possible for the majority of programmers have set up special support for getting started in Eclipse. So, if you have not done so yet, download Eclipse. Unfortunately, it is a huge program, and also requires quite a lot of system memory. But what it eats in system resources, it gives back in awesome Java tools. When you first run Eclipse, it'll ask for a workspace. Make sure that you point it to /forge/mcp/eclipse. For Forge 1.7 use "/forge/eclipse".

When you do so, Eclipse will start with one project "Minecraft" already in its Package Explorer on the left side of the screen. Expand the project, and you will see a source directory named 'src'. Expand it, and you'll see quite a lot of packages that make of Minecraft and Minecraft Forge. While you will not be editing any of these classes, feel free to read these classes to figure out what you can do or to see how Minecraft works.

Creating Packages and Classes

Modding with Forge means that all modifications are done via adding new classes. At no point, unless you are making a coremod and have a really good reason, should you be editing any other class. The classes you add should be in their own package.

To create packages and classes in Eclipse, we right click the containing context in the Package Explorer we want the package or class to be in. For packages, this is the src directory. For classes, this is the package the class belongs to. This context allows Eclipse to pre-fill in some required configuration. When we right click on the context, we select New -> Package or New -> Class.

For the Generic mod, we will use the package tutorial.generic. If you are following along with this tutorial exactly, create that package by selecting Package on the New menu. In the popup that opens, make sure the source folder is Minecraft/src and that the name is tutorial.generic. Once done, the package explorer should now show that an empty package tutorial.generic exists.

Next up, we shall create the first class of any mod: the Base Mod file. This class contains the hooks that Forge will use to bind your mod to Minecraft. As our mod for these tutorials is the Generic mod, this class will be called Generic.

Right click on the tutorials.generic package, and create a new class. The only things that matter on the dialog are the source folder, package, and name. The source folder is Minecraft/src. The package is tutorial.generic. The name is Generic.

At this point, you should have a class called Generic in the tutorial.generic package in the Minecraft/src directory. If you do not, please try again.

Source Location

You will find the packages and classes you created at /forge/mcp/src/Minecraft/.

Base Mod Class

The Base Mod class is the class that Forge loads. All your other classes will have to be registered to Forge from the base mod making it the central location for your mod. For this reason, I suggest naming the base mod class the same name as your mod. Since this tutorial series works on the Generic Mod, this class is named Generic.

In the last section, we created an empty class. Let's flesh this class out with the standard boilerplate of a mod. Replace whatever Eclipse generated with the following section.

This code does not work for 1.8. View the page source to see a 1.8 version that includes the correct SidedProxy include and needed CommonProxy setup.

Now that we've got that out of the way, you'll notice that there are a lot of @annotations and import statements (which will only get longer as you continue to mod and add more content to your mod); This is the absolute basis for creating a Mod for 1.8, But it won't do anything (at least, not yet).

Base Mod Annotations

This base mod class probably has you asking questions. Hopefully this section answers them. This section is a list of the annotations used in the Base Mod class and what they actually signify.

@Mod

Tells Forge that this is the Base Mod class. Takes three parameters.

• modid 

  A unique name for your mod. Should never be changed after your initial release.

  name 

  Human readable name for your mod.

  version 

  The version of your mod. Pick any versioning scheme you want.

@NetworkMod

Hat tip to Wuppy for this description.

Tells Forge how to handle what happens when the client xor the server has the client installed. Takes two parameters.

• clientSideRequired 

  Asks if you need this on the client to use this mod. This should be true.

  serverSideRequired 

  Asks if you need this on the server for the client to be able to connect. This should always be false, else you can't join a server if the server doesn't have the mod installed, but you do. It is false by default anyway.

  Deprecated as of 1.7

@Instance

Base Mod classes are Singletons. This is the object reference to your class that Forge uses. Make sure that the argument is the modid in @Mod. Otherwise, it'll default to the empty string, and cause problems with any mod that also does that.

@SidedProxy

This proxy is where Forge decides which class to load depending on whether or not the client or server is running. You can use this annotation on any field.

• clientSide 

  String containing the fully qualified name of the class to load for the client.

  serverSide 

  String containing the fully qualified name of the class to load for the server.

@EventHandler

This gets called on all the methods. It is 1.6.1's equivalent to @PreInit, @Init, and @PostInit. (Note that the FML events stay the same, only the annotations get changed)

For 1.6.X, need to add the following import cpw.mods.fml.common.Mod.EventHandler;

If you need help understanding this part, check out this video tutorial: http://www.youtube.com/watch?v=wClflouXP3U&list=PLrnh7I7rzm5zvPDCW6eGWhTVQh3BPh2bu&index=2

Finished

At this point, you should have the following in your Package Explorer (in addition to all the minecraft and minecraftforge packages):

• Minecraft
  • src
    • tutorial.generic

If so, you have successfully set up the boilerplate for a Forge mod, and are ready to start adding your own content.

To test your mod: Save your workspace, then press the green Run button. Minecraft should launch with your mod installed.

What's Next?

In future tutorials, there will not be as much copy pasting of entire classes. Instead, the class will be built up, with the final cleaned up result shown at the end.

• Crafting and Smelting - One of the easiest ways to allow access to new items.
• Basic items - The basics of item creation.
• Basic blocks - The basics of block creation.

• Log in / create account

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