Welcome to Creating a Minecraft Mod Using MinecraftForge. The purpose of this tutorial is to show you what is involved in setting up the environment and building a mod.
Creating a Minecraft mod requires the JDK, an SDK and/or a mod loader. There are a handful of options to create a mod for Minecraft, but for this tutorial, MinecraftForge and Eclipse will be used. One of the nice things about Java is that it's available on many platforms, so this tutorial is applicable to the platform you are working in. Windows 7+ or Mac OS X 10.8+ are recommended.
Install these first:
- Latest Minecraft launcher (Use the .jar under "Minecraft for Linux/Other" not .app on Mac to be able to use with JDK 1.8)
- Java JDK 8 (8u45 at time of writing)
- Eclipse IDE for Java Developers (Luna version at time of writing)
Download the recommended installer and src for MinecraftForge for Minecraft 1.8 (11.14.1.1334 at time of writing)
Prior to installing Forge, you will need to run Minecraft 1.8 at least once. Forge will also remind you of this if you forget.
Run the Minecraft launcher (NOTE: as a reminder, if you are on Mac OS X, it is recommended to use the minecraft.jar for this tutorial, which is the Linux/Other download of Minceraft. Not the .dmg and .app.)
Save Profile then click Play. Once Minecraft has fully launched, you can close it.
Now install Forge. Running the Forge installer, you will be prompted to install client, server, or extract. For the intents of this tutorial, only the client is needed.
Now that Forge is installed, extract the forge source zip file (not to be confused with the Extract option from the installer) to a desired location. This is where the majority of work on the mod will be done. Also feel free to rename the folder to the name of your mod. For this tutorial, forge-mod will be used.
The Forge SDK uses an open source build automation tool called gradle. If you are already familiar with gradle, great. If not, do not worry, it is fairly simple to use as long as you are comfortable using the command line.
Now on to generating the Eclipse workspace.
Open a command prompt (Cmd.exe or Terminal.app) and cd to the forge source folder from earlier.
$ cd forge-mod
To generate the workspace, use the gradlew build script (gradlew.bat on Windows):
$ ./gradlew setupDecompWorkspace eclipse
This command will link with Minecraft and create the appropriate Eclipse workspace files. You are now ready to begin work on your mod in Eclipse.
Launch Eclipse, and if this is the first time launching it, you will be prompted to select a workspace when it starts. If you don't get the workspace prompt, select File -> Switch Workspace -> Other... to bring up the dialog.
The Eclipse workspace is in the forge-mod/eclipse folder. You can either type in the path to it, or click Browse... and navigate to choose the eclipse folder that is in the root of forge-mod.
You should now see a window that looks something like this (expand the Minecraft node in Package Explorer):
Forge includes an ExampleMod class you may use as reference. It is not used in this tutorial, so you may remove it if you like.
Right-click on src/main/java in Package Explorer and choose New -> Package:
Java recommends using the reverse-domain naming convention, so call the package com.mymod.tutorial then click Finish.
You now have an empty package. This is where all the source code for the mod will go.
Create the main class for MyMod. Right-click on com.mymod.tutorial in the Package Explorer and choose New -> Class:
Java recommends camel-case naming for classes, so let's name the class MyMod then click Finish.
Your workspace should now look like this:
Now it's time to add strings to the MyMod class that will be used to register the mod with Forge. Add these to the MyMod class:
public class MyMod {
public static final String MODID = "mymod";
public static final String NAME = "My Minecraft mod";
public static final String VERSION = "1.0";An annotation to the MyMod class is needed to tell Forge this is the base mod class:
@Mod(modid = MyMod.MODID,
name = MyMod.NAME,
version = MyMod.VERSION)
public class MyMod {At this point, you'll probably notice errors building or if you have Build Automatically enabled by default in Eclipse. You can have Eclipse fix this by clicking on the icon in the margin and selecting the import 'Mod' option:
Next, add the rest of the boilerplate code for a mod:
// Tell Forge what instance to use.
@Instance(value = MyMod.MODID)
public static MyMod instance;
@EventHandler
public void preInit(FMLPreInitializationEvent event) {
}
@EventHandler
public void load(FMLInitializationEvent event) {
}
@EventHandler
public void postInit(FMLPostInitializationEvent event) {
}Your MyMod.java file should now look like this:
package com.mymod.tutorial;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.Mod.EventHandler;
import net.minecraftforge.fml.common.Mod.Instance;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;
import net.minecraftforge.fml.common.event.FMLPostInitializationEvent;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
@Mod(modid = MyMod.MODID,
name = MyMod.NAME,
version = MyMod.VERSION)
public class MyMod {
public static final String MODID = "mymod";
public static final String NAME = "My Minecraft mod";
public static final String VERSION = "1.0";
// Tell Forge what instance to use.
@Instance(value = MyMod.MODID)
public static MyMod instance;
@EventHandler
public void preInit(FMLPreInitializationEvent event) {
}
@EventHandler
public void load(FMLInitializationEvent event) {
}
@EventHandler
public void postInit(FMLPostInitializationEvent event) {
}
}Now that the main class is all set, modify the build.gradle file to match the main class's information.
Open up build.gradle and you should see these lines near the top:
version = "1.0"
group= "com.yourname.modid" // http://maven.apache.org/guides/mini/guide-naming-conventions.html
archivesBaseName = "modid"Change version, group, and archivesBaseName to match VERSION, package name, and MODID from before. So your build.gradle should now contain:
version = "1.0"
group= "com.mymod.tutorial"
archivesBaseName = "mymod"Now you can build the jar file and test it out.
In a cmd prompt, run the gradlew script with build and jar as arguments:
$ ./gradlew build jar
If there were no errors, you should now have a .jar file named mymod-1.0.jar in forge-mod/build/libs. In order for Forge to load the mod, it needs to be copied to the mods folder Forge creates in the .minecraft folder. The .minecraft folder location depends on your OS:
| OS | Path |
|---|---|
| Windows | %appdata%\.minecraft |
| Mac OS X | ~/Library/Application Support/minecraft |
(If there is no mods folder, create one.)
Once your .jar has been copied, launch Minecraft. Make sure you have the Forge profile selected before you click Play.
After you click Play and Minecraft launches, there should be a Mods button in the main menu. Clicking that will list the mods Forge has loaded. You should now see MyMod in that list:
Congratulations! You just created and ran a Forge mod.
SteelSeries Engine 3 GameSense™ events are formatted using JSON. So it is recommended to use the latest JSON library for Java. You can get the latest JSON.jar from the mvnrepository.
Put the JSON .jar file in a jars folder in the root of forge-mod:
Next, add the dependency to build.gradle and regenerate the Eclipse workspace.
Open up the build.gradle file again, and find the top-level section for dependencies (NOT dependencies under buildscript) :
dependencies {
// you may put jars on which you depend on in ./libs
// or you may define them like so..
//compile "some.group:artifact:version:classifier"
//compile "some.group:artifact:version"
...
}Add compile files('jars/json-20140107.jar') to the contents of dependencies:
dependencies {
// you may put jars on which you depend on in ./libs
// or you may define them like so..
//compile "some.group:artifact:version:classifier"
//compile "some.group:artifact:version"
compile files('jars/json-20140107.jar')
...
}Exit Eclipse if it's still running and regenerate the Eclipse workspace and build.
$ ./gradlew eclipse build
You will also need to copy the JSON jar to the mods folder in .minecraft. You will only have to do that once, unless you use a newer version of the JSON jar.
Now that you have a development environment set up, check out the Minecraft Meet SSE tutorial to learn how to create handlers and events for GameSense™.