Minecraft Java McRegion to Anvil Converter Map Converter

This tool converts Minecraft Java Edition McRegion (Beta 1.3 - 1.2.5) worlds to Anvil format.

The project is based on the McRegion to Anvil Converter created by Jens Bergensten at Mojang in 2012. It has been modified to support parallel processing (multithreading) to speed up the conversion process.

About

This fork was created by RhysB for use on RetroMC to facilitate routine conversion of McRegion worlds to Anvil format, enabling modern tools like Overviewer to render the map.

Performance Improvements

Performance improvements observed when converting RetroMC (approximately 30gb) from McRegion to Anvil format on a AMD Ryzen 9 5950X:

Cores	Time (s)	Speedup
Best Sequential	5976	N/A
1	6156	0.97
2	2976	2.01
4	1497	3.99
8	774	7.72
16	441	13.55
32	318	18.79

Analysis

The performance data demonstrates significant improvements when increasing the number of threads for the conversion process. Key observations include:

• Sequential vs. Single Thread: The single-threaded conversion process is slower than the original sequential process. This is likely the result of additional overhead introduced by the multithreading implementation.

  • ExecutorService Optimization: The ExecutorService may incur some overhead even with a single thread, leading to a slight performance decrease.

• Overheads and Limits: Despite the impressive scaling, the speedup is slightly less than the ideal linear speedup at higher thread counts. Potential reasons include:

  • I/O Bottlenecks: Disk I/O operations might become a limiting factor, preventing perfect linear scaling.
  • CPU Saturation: As the CPU approaches full utilization, additional threads contribute less to overall performance improvement.

Usage

1. Download the latest release from the releases page.

2. Run the converter with the following command:

   java -jar AnvilConverter.jar <base folder> <world name> [thread count]

   • <base folder>: The full path to the folder containing Minecraft world folders.
   • <world name>: The folder name of the Minecraft world to be converted.
   • [thread count] (Optional): Number of threads to use for conversion. Defaults to 1 if not specified.

3. Examples:

   • Convert world using 1 thread:

     java -jar AnvilConverter.jar /home/jeb_/minecraft world

   • Convert world using 4 threads:

     java -jar AnvilConverter.jar /home/jeb_/minecraft world 4

Example Worlds/Datasets

Example worlds and datasets, such as historical RetroMC and BetaLands world downloads, can be found on archive.johnymuffin.com.

License

Modifications made to this project are licensed under the MIT License. See LICENSE for more information.

The original McRegion to Anvil Converter was created by Jens Bergensten at Mojang and includes the following notice:

 * Copyright Mojang AB.
 * 
 * Don't do evil.
 */