ChunkLoader

Admin-controlled circular chunk pre-generation plugin for Paper 1.21.x

What is ChunkLoader?

ChunkLoader lets server admins pre-generate chunks in a perfect circular area around their position — similar to Chunky, but simpler and focused on pure admin control.

No more lag spikes when players explore new areas. Pre-generate your world before opening the server.

Features

Circular selection — only chunks within exact Euclidean radius are processed (not a square)
Batch processing — chunks load in small configurable batches, no server freezes
TPS/MSPT throttling — automatically slows down when your server is under load
Boss bar progress — live progress bar shown to all online players
Persistent jobs — progress is saved after every batch; server restarts resume automatically
Console + chat feedback — percentage, ETA, speed, TPS shown in real time
Full command set — start, pause, resume, cancel, status, reload

Commands

Command	Description
`/chunkloader <radius>`	Start generation in a circular radius around you
`/chunkloader status`	Show current job progress
`/chunkloader pause`	Pause the job (progress saved)
`/chunkloader resume`	Resume a paused job
`/chunkloader cancel`	Cancel and discard the job
`/chunkloader reload`	Reload config.yml

Aliases: /cl, /cloader

Permissions

Permission	Description	Default
`chunkloader.use`	Use all `/chunkloader` subcommands	OP
`chunkloader.admin`	Includes use + config reload	OP

Configuration

chunks-per-batch: 10         # Chunks per batch (normal conditions)
batch-delay-ticks: 5         # Ticks between batches (normal)
tps-threshold: 18.0          # Switch to slow mode below this TPS
mspt-threshold: 45.0         # Switch to slow mode above this MSPT
slow-batch-size: 3           # Chunks per batch (stressed server)
slow-delay-ticks: 20         # Ticks between batches (stressed server)
progress-interval-seconds: 5 # How often to print progress (0 = disable)

How It Works

Stand where you want the center of generation to be
Run /chunkloader <radius> — e.g. /chunkloader 100
ChunkLoader computes every chunk within the circular radius (not a square)
Chunks are loaded in batches using Paper's async chunk API — zero main thread blocking
Progress is displayed on a boss bar visible to all players
If the server restarts, the job automatically resumes from where it left off

Circular Shape

/chunkloader 3 processes approximately:

      █ █ █
    █ █ █ █ █
  █ █ █ █ █ █ █
  █ █ █ █ █ █ █
  █ █ █ █ █ █ █
    █ █ █ █ █
      █ █ █

Only chunks whose distance from the center satisfies √(dx² + dz²) ≤ radius are included.

Requirements

Paper 1.21.x (1.21.4 recommended)
Java 21+

Spigot / Bukkit are not supported — this plugin uses Paper-specific async chunk loading APIs.

Installation

Download ChunkLoader-1.0.0.jar
Place it in your server's plugins/ folder
Restart the server
Configure plugins/ChunkLoader/config.yml as needed
Run /chunkloader <radius> in-game