BmsTWO

BmsTWO is an editor for bmson files, the music-game format derived from BMS.

BmsTWO is a continuation fork of BmsONE. Its lineage is:

• excln/BmsONE — original upstream (last binary release: beta 0.2.1, Sept 2017).
• djkero/BmsONE — 2020 fork that added EZ2 (EZ2ON / EZ2AC) mode support and skins for both player sides, the 5K ONLY / 14K ANDROMEDA modes, and an updated mode_hint spec. This is the base of the present fork.
• This fork continues from djkero with compiler/deprecation cleanup, ASan-detected leak fixes, and ongoing stability work.

EZ2 support

The EZ2 mode support inherited from djkero is kept as-is in this fork:

• The default mode_hint on a new file is 5K STD.
• EZ2 skins are bundled, with player-side selection under Toolbar → View → Scratch → Player X.
• EZ2 modes ignore judge_rank and total (EZ2 handles timing/life its own way — see EZ2_INFO.txt for the judgement/life delta reference).
• EZ2_TEMPLATE.bmson is provided as a starting template.

What's new in BmsTWO

Everything below was added on top of the djkero/BmsONE base. End-user documentation for these lives in the project wiki (source under docs/).

Editing & navigation

• Copy / cut / paste of sound notes, pasting at the cursor and snapping to the grid when snap is on.
• Fill notes evenly between two selected notes.
• Custom bar division — toggle a bar line at the cursor to split/merge measures.
• BGA editing — a dockable editor for BGA headers and the base / layer / poor event lanes.
• STOP events — editable, and now honored by the time/playback engine (playback and WAV export pause at stops).
• Long notes — a one-key Toggle Long Note command, plus an optional keysound re-trigger at an LN's release (the up extension — see Format below).
• Keysound / lane lock — stop note drags from accidentally reassigning a note's lane (keysound).
• MIDI import — drop a MIDI file onto a channel to lay out slice notes.
• Go To — jump to a measure, pulse, or time.
• Richer selection — select every note in a channel, and inspect/sort the current selection in a dedicated panel.

Panels & workflow

• Classic BMS Mode — a usable layout and charting flow for pre-cut-sample songs (hundreds of keysound channels): channels are merged into name-grouped, overlap-packed background lanes; clicking a note auditions its sample, writing a key note keys the sample the music actually has at that time (or slices an ongoing one), deleting a keyed note un-keys it, and right-clicking splits a sample (the remainder returns to the background) — so charting never alters the music. Reset All Notes to BGM un-charts back to a blank canvas of samples.
• Statistics dock — note counts, average / peak NPS, per-lane distribution.
• Charts dock — list and switch between the charts in a song folder (sabun workflow).
• Keysounds panel — add / remove / reorder / replace the shared keysound list in one place.
• Selection dock — sortable list of the current selection; double-click to jump.
• Autosave & crash recovery — periodic snapshots of unsaved work, offered back after an abnormal exit.
• Configurable keyboard shortcuts — rebind any menu command, with conflict detection, in Preferences.
• Multi-track sample preview — preview several selected channels mixed together.

Appearance

• Modern dark theme (toggle in Preferences; Classic restores the original look): Fusion palette, tiered gridlines, alternating measure shading, rounded notes / long-note capsules, per-channel color-coding with custom overrides, monospace numeric fields, and crisp high-DPI rendering.

Format

• bmson extensions — a few optional non-standard fields (up LN-release re-trigger, x_stop keysound cutoff, x_color channel color) that degrade gracefully in other players. See docs/Bmson-Extensions.md.

Under the hood

• Qt 6 port, a dependency-free crash handler, numerous crash/UB/leak fixes, smart-pointer ownership refactors, faster bulk channel operations, a headless ASan/UBSan fuzz harness, and CI that produces Windows and Linux builds.

Building

This software is built with Qt 6 and C++17, using qmake (the qt5compat module is required for core5compat).

qmake6 src/bmstwo.pro
make

Or open src/bmstwo.pro in Qt Creator.

libogg and libvorbis are bundled in the source code (under src/libogg and src/libvorbis), so no external audio libraries are required.

AI development & transparency

In the interest of transparency, the BmsTWO fork was developed as a human-directed, AI-assisted project:

• The maintainer (Roganis) owns and directs the project: setting goals and priorities, making the design and scope decisions, reviewing the work, running and validating the application (interactive/GUI testing), and owning releases and overall responsibility for the project.
• An AI coding assistant (Anthropic's Claude, via Claude Code) did the hands-on implementation under that direction: writing the feature code, bug fixes, refactors, and this documentation, and verifying each change with compiler builds and the headless AddressSanitizer/UBSan test harness.

In short: the human decides what gets built and confirms it works in practice; the AI does most of the writing and automated checking. Automated verification (builds, sanitizer/fuzz harness) does not replace real-world use — please report anything that misbehaves.

License

BmsTWO is distributed under the GNU General Public License v3.0. See the LICENSE file for the full text.

Third-party components:

• Qt is used under the GNU LGPL.
• libogg and libvorbis are bundled and used under the Xiph.org BSD-style license. See the COPYING directory for their license texts.

Acknowledgments

• Original BmsONE by excln; EZ2 mode support by djkero.
• Qt — Copyright (C) The Qt Company Ltd and other contributors.
• libogg / libvorbis — Copyright (c) 2002–2015 Xiph.org Foundation, available at Xiph.org.

This page is synced from README.md in the BmsTWO repo.