Henkan
By
@Kaanreal
- 4 Devlogs
- 39 Total hours
The reliable VSRG converter. (better doc on github)
Devlog — Countdown fix + WASM sync
Fixed countdown being on by default when converting Etterna to osu. Added
Countdown: 0 to the [General] section in the converter, the dummy diff
generator, and the TypeScript equivalent.
Discovered the web version was using a stale pre-built WASM binary that
didn’t have any of the Rust fixes. Created wasm-core/ — a new crate that
builds WASM from the same Rust source via #[path] references. No code
duplication.
Added npm run build:wasm for local rebuilds and a CI job that auto-rebuilds
WASM on push to main so it never goes stale again
Ship #1
Pending review
Hello, I made an osu!mania ↔ Etterna converter called Henkan (変換).
I started the project because I noticed that most existing converters didn’t preserve maps correctly. Timing would drift, BPM changes would be lost or simplified, and long notes would often break during conversion. I wanted to build a converter that focused on accuracy instead of quick conversions.
Henkan converts beatmaps between osu!mania (.osu / .osz) and Etterna/StepMania (.sm) while preserving the original chart as closely as possible. It keeps millisecond-accurate note timing, supports multiple BPM changes, correctly converts long notes, preserves metadata such as title, artist, creator, difficulty, and preview point, and keeps background references.
The application is written as a native desktop app using Rust, Tauri, and React, making it lightweight and fast on Windows, macOS, and Linux. It also supports converting entire packs, allowing users to process many maps at once instead of converting them individually.
One limitation is that scroll velocity (SV) is not converted from osu!mania to StepMania because the .sm format does not have an equivalent representation for osu!’s green-line SV changes.
My goal with Henkan is to provide a reliable converter that players can trust to preserve their charts accurately instead of introducing timing errors or losing important map information.
Hello, today I polished and finished the newest version of Henkan! This version is now the most stable version that also introduced an web based app.
Hello, today I fully worked on making my project available for the web via Vercel! I had to solve many issues like permission issues , timing issues , upload issues and more , I eventually fixed it and can say that it’s working stable now! Now I have to sleep…
Hello, this is my first log! I have to admit that my project is kinda niche but it fills the gaps of the rhythm game community. Short introduction : Im making an advanced osu!mania ↔ Etterna beatmap converter to simplify the mapping and playing of maps. I really depend on making it high performance and feature rich, for example: I had to go through many issues like fixing timing issues , conversion logic , or other things, but I learned from it and fixed them in a way that sets other converters in the ground. I started my project a few days before I found out about stardance hack club so im kinda sad that this time doesn’t count :(. Anyways, im happy to share my progress from now on. Today I focused on developing the CLI for my project and polishing some things, I think it turned out great
