Introduction

Generator API is a tool that automatically batch-generate files for datapack, resource pack, etc.

You might be confused, how does the Generator API know

• What to generate?
• When it should generate?
• Where to generate?
• Generator for what?
• How the generated files injected into the game?

Let's answer these questions.

Pack Handler

Pack handler creates & manages a file-pack that can be injected by the handler into the game. The file-pack is a directory (not a zip file) using same structure that can be a resource pack or a datapack, depending on the type of the pack handler.

The pack handler is defined and registered in the mod code. You only need to know where the file-pack is located so that you know where you put your generator definition files.

By default, Croparia IF provides 2 pack handlers:

• Resource Pack Handler: croparia:resourcepack, file-pack located at ${game}/croparia/resourcepack
• Datapack Handler: croparia:datapack, file-pack located at ${game}/croparia/datapack

Refer to the Pack Handler documentation for more details.

Generator

The generator can be defined from a file located at generators folder in the file-pack from a pack handler.

It contains a template that describes what to generate, specifies the entries that provide the information required to replace the placeholders in the template, and tells pack handler where to correctly place the generated files.

This is what you are going to create as a modpack developer.

Refer to the Generator documentation for more details.

Lifecycle

Here we talk about when the generator will generate files, and how it works in the game.

Lifecycle in Game

The generation will be triggered every time the game is trying to load resource pack or a datapack. Thus, we need to understand the Minecraft lifecycle first.

The resource pack will be loaded only in client when:

• The game is starting up. Resource pack handlers are injected here.
• When you join a world (integrated server starting).
• When manually reloading the resource pack in the game.

The datapack will be loaded in both client & server when:

• The game/server is starting up. But only the world-gen related features are loaded, no tags, recipes, etc. Datapack handlers are injected here.
• When joining a world (server preparing world), all features are loaded.
• When manually reloading the datapack in the game, all features are loaded.

As you can see, we don't have access to the tag system until the world is started, but something needs it to generate files, like Crops whose material might be defined by item tags. So, Croparia IF will launch an extra reload for datapack when the world is started, which will allow us to access the tag system and generate correct files.

Lifecycle per Process

In each generation process, the following things will happen:

1. Pack handlers rewrite the meta file of the file-pack to make sure it is a valid resource pack/datapack.
2. Pack handlers clear the previous generated files in the file-pack.
3. Pack handlers move built-in generators to the file-pack.
4. Pack handlers load the generators from generators folder under the file-pack folder.
5. Pack handlers trigger the generation for each loaded generator. The generated file are cached in memory.
6. Pack handlers dump the generated files into the file-pack, and clear the cache.
7. The injected file-packs are loaded by the game.

Next

Now you should have a basic understanding of how the generator works. Next, you can try to create your own generator following the Tutorial.