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Plugin Development

A good way to start developing plugins is to take a look at the source code of existing plugins to dive into Chunky's plugin API. Interfaces and methods that are considered stable for plugin use are annotated with the @PluginApi annotation in Chunky's code.

If you have questions about the API or need any help, the #tech channel on our Discord server is a good place to start.

Gradle configuration

To build a plugin for Chunky, you need, well, Chunky. More precisely, chunky-core is needed as a dependency1 in order to build the plugin (and also provide you code completion and javadoc). We recommend using Gradle, and a simple "build.gradle" config for a plugin could look like this:

apply plugin: 'java'

compileJava {
  sourceCompatibility = JavaVersion.VERSION_1_8
  targetCompatibility = JavaVersion.VERSION_1_8

repositories {
  maven {
    url ''

dependencies {
  compileOnly 'se.llbit:chunky-core:2.4.0'

Plugin manifest

Similar to Bukkit plugins, Chunky plugins contain a manifest file that contains information about the plugin name, version, and, most importantly, which class of it Chunky should load. This file must be named "plugin.json" and be located at the root of the plugin JAR file.

  "name": "Demo Plugin",
  "author": "You",
  "main": "com.example.chunkydemoplugin.DemoPlugin",
  "version": "1.0",
  "targetVersion": "2.4.0",
  "description": "A demo plugin."

The fields should be pretty self-explanatory. The targetVersion is the version of Chunky that your plugin supports.2 If any other Chunky version is used, a warning will be printed to the console to notify the user, but Chunky will still attempt to load the plugin.

The fully-qualified class name in main is the main class of your plugin, which must implement the se.llbit.chunky.Plugin interface.

Plugin entrypoint

For the demo plugin, the implementation could look like this. Note how the class name and package correspond to the main value from the manifest:

package com.example.chunkydemoplugin;

import se.llbit.chunky.Plugin;
import se.llbit.chunky.main.Chunky;
import se.llbit.chunky.main.ChunkyOptions;
import se.llbit.chunky.ui.ChunkyFx;

public class DemoPlugin implements Plugin {
  public void attach(Chunky chunky) {
    // TODO add your plugin functionality here

  public static void main(String[] args) throws Exception {
    // Start Chunky with this plugin attached
    Chunky chunky = new Chunky(ChunkyOptions.getDefaults());
    new DemoPlugin().attach(chunky);

About the main method

The main method is added only for convenience. This way, you can launch Chunky with this plugin enabled directly from within your IDE, which is also useful for attaching a debugger. When loading a plugin from a JAR, Chunky will create an instance of the plugin class and invoke the attach method. You should put all plugin initialization logic there.

Demo plugins

To demonstrate some features of the Plugin API, llbit created a few demo plugins.

The Ambient Occlusion plugin and the Depth Buffer plugin use a deprecated API to add renderers to Chunky. The Chunky AOV plugin adds these renderers using the new API.

  1. leMaik's Maven repository contains all release builds of Chunky starting with 2.3.0 as well as the nightly builds as maven snapshots. 

  2. Chunky doesn't support range checks yet but they may be added in the future. That would allow you to specify e.g. >= 2.4.0 for compatibility with 2.4.0 or later.