Classic BMS Mode

(formerly “Grouped BGM Lanes”)

For songs whose samples are already cut (often hundreds of one-shot keysound channels) — the classic BMS way of charting — the normal one-column-per-channel layout becomes unusably wide. Classic BMS Mode reorganizes those channels into compact, name-grouped background lanes so you can read the whole song and chart from it.

Enable: View → Classic BMS Mode (persisted).

What it does

Name grouping. Channels are grouped by the leading part of their name before a trailing number — piano_03, piano_04 → one piano lane; key_0348 → key. Each group is one background lane.
Overlap sub-lanes. Notes within a group that overlap in time are split into the minimum number of side-by-side sub-lanes so nothing collides; a group widens only as much as it needs to.
Editor-native look. Same dark background, bar/beat/fine gridlines, per-channel colors (with custom-color overrides), time cursor line, and hover outlines as the rest of the editor. A label strip at the top names each group; the current sample's group is tinted and its label highlighted, just like the current channel's column in the standard view.
Live. The grouping rebuilds automatically as you edit, and the right-edge minimap (whole-chart scroll overview) stays available.

Working in this view

Hover → the standard time cursor and status-bar readout (measure / beat / real time); hovering a note outlines it and shows its info, exactly like the standard lanes.
Click a note → selects that sample as the current channel and auditions it (so you hear the keysound without opening the channel tab).
Right-click a lane → the same channel context menu as a standard column: preview, move left/right, select notes, set/clear color, delete.
Write a key note (write mode, on the playfield) → keys the sample the music actually has at that time, not the last-selected one. Because a channel holds one note per time, the existing sample note is moved onto the key lane — the music is preserved, only what triggers it changes. As you move down the timeline each note grabs the correct sample automatically.
Delete a keyed note → un-keys it: the sample returns to the BGM lane rather than being deleted, so deleting a chart note never deletes the music.
Right-click on the playfield (write mode, empty spot) → splits the sounding sample at that tick: the remainder returns to the background as a continuation note, so a keyed note above the split only triggers the first part — the total audio stays identical. Right-click an existing split to heal it. (Right-clicking a legacy x_stop marker clears the stop, un-silencing the remainder.)
Draw a long note → the sample is split automatically at the LN's release: the long note keys the head slice, the remainder returns to the background — no manual right-click needed. (Skipped if another note already sits at the release tick, if the sample has ended by then, or for up notes.) Right-click the split to heal it.
Reading the lanes: every continuation/cut note carries a red cross at its trigger tick — the previous sound is cut there and the marker under the cross is its remainder. A marker without a cross is a genuinely new keysound.
No Shift needed. In this view a freshly placed note defaults to a new-sample trigger (normally Shift); Shift instead requests a continuation.
Snap to Sample. The magnet (Snap to Grid, Ctrl+T) changes function in this mode: instead of locking the cursor to BPM fractions, it locks to the nearest sample in the currently selected lane (the highlighted name-group). Select a sample in a group, then chart on the playfield — the cursor jumps from sample to sample, so every written note lands exactly on a keysound even when the song is off-grid. With no sample selected (or an empty group) the magnet falls back to the normal grid.
Moving notes between lanes is still done in Edit mode (write mode no longer shows a misleading move cursor).

Pairs with

The Keysounds panel — list/add/remove/reorder the shared keysound list and jump to a sample.
Channel Find (Channel → Find) — filter the channels by name.

Notes & limitations

Sample matching on write is by the exact (snapped) time. With the magnet on, snapping targets the selected lane's samples directly, so off-grid keysounds are matched exactly; only with the magnet off (or nothing selected) can a click miss a sample and fall back to the sounding channel.
Group/lane widths are fixed (14 px per sub-lane) in this first version.

This page is synced from docs/Classic-BMS-Mode.md in the BmsTWO repo.