opsu! is an unofficial open-source client for the rhythm game osu!, written in Java using Slick2D and LWJGL (wrappers around OpenGL and OpenAL).

opsu! runs on Windows and Linux.

Take a look at the original project if you would like to do so:

• itdelatrisu/opsu
• fluddokt's Android port

Specially, you may hope to read relevant wiki articles as well.

Get a copy of opsu! from the releases page.

The minimum requirement for JRE isn't determined yet. But I recommend OpenJDK 21.0.2, because I'm using it on my own computer.

opsu! requires "beatmaps" to run, which contain the songs and gameplay data. These can be downloaded directly through opsu! in the downloads menu, or manually from the osu! website (needs an available osu! account) and mirror sites. Place any manually downloaded beatmaps (in .osz format) in the Import/ directory for opsu! to unpack them automatically. Currently opsu! only supports osu!(standard) mode beatmaps!

If osu! is installed, opsu! will attempt to read beatmaps from the osu! installation location. The beatmap directory can also be changed by setting the "BeatmapDirectory" value in the generated configuration file opsu.cfg.

opsu! will parse all beatmaps and update the database when launched, which can take a while for the first time. If no beatmaps are found, the game will prompt you to download some to get started.

Game settings can be changed in the options menu, accessed by clicking the "Other Options" button in the song menu. The "Music Offset" value will likely need to be adjusted initially, or whenever hit objects are out of sync with the music.

Then are you going to change the custom song? Yes you can, by doing the following:

• Put your favorite theme song under the Songs directory.
• Edit the .opsu.cfg file:
  • Key ThemeSong: theme.mp3,[Title],[Artist],[Total Length in Miliseconds]
  • Key ThemeSongTiming: [Time],[BeatLength],[Meter],[SampleSet],[SampleIndex],[Volume],0,0. Refer to the Timing wiki for further information.
• Run opsu! and enjoy!

The following files and folders will be created by opsu! as needed:

• .opsu.cfg: The configuration file. Most (but not all) of the settings can be changed through the options menu.
• .opsu.db: The beatmap cache database.
• .opsu_scores.db: The scores and player database.
• .opsu.log: The error log. All critical errors displayed in-game are also logged to this file, and other warnings not shown are logged as well.
• Songs/: The beatmap directory (not used if an osu! installation is detected). The parser searches all of its subdirectories for .osu files to load.
• Skins/: The skins directory. Each skin must be placed in a folder within this directory. Any game resource (in res/) can be skinned by placing a file with the same name in a skin folder. Skins can be selected in the options menu.
• Replays/: The replay directory. Replays of each completed game are saved as .osr files, and can be viewed at a later time or shared with others.
• Import/: The import directory. All beatmap packs (.osz) and skin packs (.osk) are unpacked to the proper location. All replays (.osr) are moved to the replay directory, and their scores saved to the scores database.
• Screenshots/: The screenshot directory. Screenshots can be taken by pressing the F12 key.
• Natives/: The native libraries directory. (If exists)
• Temp/: The temporary files directory. Deleted when opsu! exits. (If exists)

opsu! is distributed a Maven project.

Note: Due to technical reasons, the support for Gradle has been temporarily dropped. Chances are that we would add it back in the future.

Maven builds are built to the target directory.

• To run the project, execute the Maven goal compile. After compiling it will automatically show up.
• To create a single executable jar, execute the Maven goal package -Djar. This will compile a jar to target/opsu-${version}.jar with the libraries, resources and natives packed inside the jar.
  • Setting the "XDG" property (-DXDG=true) will make the application use XDG folders under Unix-like operating systems.
  • Setting the "exclude" property to "ffmpeg" (-Dexclude=ffmpeg) will exclude FFmpeg shared libraries from the jar.

See the contributing guidelines for details.

This software was originally created by Jeffrey Han (@itdelatrisu). All game concepts and designs are based on work by osu! developer Dean Herbert (@ppy). Other credits can be found here.

This software is licensed under GNU GPL version 3. You can find the full text of the license here.