osu2sm-NEXT

A reworked fork of osu2sm that decouples from the osu! install layout, produces StepMania-5.1-conformant simfiles, and ships a GUI front-end.

The conversion core (rekey / remap / rate / select / align / space / simultaneous / filter / pipe) is unchanged from upstream — every node still produces the same in-memory Simfile representation it always did. What changed is the edges: how simfiles get in, how they get out, and how the user drives the tool.

What's new

• Decoupled input. OsuLoad::fix_input defaults to false, and the auto-detect of an osu! install is opt-in. You can point the tool at any folder of .osu files — no need for a full osu! installation nearby.
• SmLoad source. A new SmLoad node reads existing .sm files (e.g. a StepMania song group) and feeds them through the same downstream pipeline. Useful for re-rating, re-keying or simply re-packing an existing collection.
• Decoupled output. SimfileWrite::in_place defaults to false, and the auto-detect of a StepMania install is opt-in. You can write to any folder.
• Standard StepMania layout. Simfiles are written as <group>/<song>/<title>.sm, matching the convention used by the reference packs under StepMania 5.1/Songs/<group>/<song>/<files>. A FlatInGroup layout is available for quick flat dumps.
• SM 5.1 field cleanup. The output drops the upstream-osu2sm attribution comment, normalises f64 precision (3 decimals, trailing zeros trimmed), clamps #SAMPLESTART to non-negative, fixes #SAMPLELENGTH to a 12-second preview instead of the full song length, and empties the *_TRANSLIT and CREDIT fields by default.
• Graphical front-end. cargo build --features gui produces osu2sm-gui. It is deliberately narrow: pick the osu! song folder, pick a StepMania song group, press 转换. The pipeline is pinned to 4K mania → dance-single (osu2sm::pipeline_4k); no RON editing.
• dry_run mode. Flip the toggle and the writer logs every file it would write without touching the filesystem.

Getting started

There are two binaries. Windows builds of both are attached to the latest release; the rest of this section builds from source.

CLI

cargo build --release
./target/release/osu2sm examples/default.config.txt

If no config path is supplied, the CLI looks for <exe-name>.config.txt next to the binary, falling back to a freshly written default.

GUI

cargo build --release --features gui
./target/release/osu2sm-gui

It does exactly one thing: osu! 4K mania → StepMania dance-single.

1. Pick the osu! song folder (e.g. D:\osu!\Songs) and the target song group (e.g. D:\StepMania 5.1\Songs\MyPack). Both rows accept drag-and-drop, and the input folder is scanned up front so you can see how many charts are 4K before converting.
2. Optionally tick 试运行 (resolve and log every path, write nothing), 跳过已存在 (leave an existing .sm untouched) or 复制音频/背景 (off = write .sm only).
3. Press ▶ 转换.

The status bar counts beatmapsets; conversion runs on a worker thread and can be cancelled between beatmapsets. Charts that are not 4K mania are skipped and reported in the log. On Windows the binary is linked with the windows subsystem, so no console window ever appears (debug or release); feedback goes to the log panel at the bottom of the window instead, panics are appended to %LOCALAPPDATA%\osu2sm\crash.log and shown in a dialog, and a failed start is reported in a dialog too. Paths and toggles are remembered in %LOCALAPPDATA%\osu2sm\gui-state.txt.

The GUI never reads or writes a RON config, does not expose standard, Remap, Align, Space, SmLoad, in_place or cleanup, and always writes the standard <group>/<song>/<title>.sm layout. For anything outside that shape, use the CLI.

Configuration

Config files are CLI-only — the GUI builds its Opts in code. The config is a RON document. See examples/default.config.txt for the full annotated example. The two source options are mutually exclusive at the top of the pipeline:

// Either:
OsuLoad((input: "C:/path/to/osu/Songs", ...)),
// ...or:
SmLoad((input: "C:/StepMania 5.1/Songs/ettgroup", recursive: true, ...)),

…and the sink is configured with:

SimfileWrite((
    output: "C:/StepMania 5.1/Songs/MyPack",
    layout: PerSongFolder,        // or FlatInGroup
    copy: [Copy, Symlink, AssertIdentical],
    in_place: false,
    cleanup: false,
    fix_output: false,
    dry_run: false,
)),

Output format

A converted .sm looks like this (key fields shown):

#TITLE:L0V3;
#SUBTITLE:;
#ARTIST:E0ri4;
#TITLETRANSLIT:;
#SUBTITLETRANSLIT:;
#ARTISTTRANSLIT:;
#CREDIT:;
#BACKGROUND:bg.jpg;
#MUSIC:audio.mp3;
#OFFSET:0.599;
#SAMPLESTART:0;
#SAMPLELENGTH:12.000;
#DISPLAYBPM:172;
#BPMS:0=172;
...
//---------------dance-single - Hard----------------
#NOTES:
    dance-single:
    ...

Compare against the reference pack under StepMania 5.1/Songs/ettgroup/<song>/<title>.sm for the conventions this codebase targets.

License

GPL-3.0 — see LICENSE.