Generation

README.md

@@ -105,11 +105,13 @@ Identical notation bodies share layout and body rasterization even when titles o
 
 The build-time pipeline is Soundslice/MuseScore -> `.xml` -> musical model and rhythm plans -> part generation -> JSON, engraved PNG pages, generated-tone audio, Pico title artwork, and a read-only catalog database. Sources in `data/songs/` retain the seven-section performance form. Four-digit numbered sources in `data/practice/` (currently `0001.xml` through `0366.xml`; `0000.xml` is also valid) produce one pass each of **acoustic accompaniment**, **electric melody**, and **vocal melody**. Both categories use the authored musical key, with no key variants or key-selection menu. Duplicate titles never merge exercises.
 
-Accompaniment uses deterministic four-bar phrase cycles: a two-bar motif repeats with a one-beat variation in the fourth bar when a suitable candidate exists. Acoustic provides the foundation; electric accompaniment responds to the melody and acoustic attacks. Selection considers harmonic coverage, density, collisions, and available space, and restarts at section or meter changes. Rhythm snippets supply attacks, rests, and written durations; structured harmony supplies chord tones. N.C. and absent harmony remain silent. Authored melody, solo slashes, and the seven-section form retain their roles. Unsupported accompaniment meters and mid-measure meter changes fail explicitly.
+Accompaniment uses deterministic four-bar phrase cycles: a two-bar motif repeats with a one-beat variation in the fourth bar when a suitable candidate exists. Acoustic has independent bass and upper-chord rhythms, including simultaneous attacks, sharing a playable grip. Bass alternates root/fifth unless an explicit bass or playability requires otherwise. Electric accompaniment responds more sparsely with stabs lasting at most a quarter note. Rhythm snippets supply attacks and rests; structured harmony supplies chord tones. N.C. and absent harmony remain silent. Solo slashes and the seven-section form retain their roles. Unsupported accompaniment meters and mid-measure meter changes fail explicitly.
 
 There are no musical genre presets, genre defaults, or genre metadata. Obsolete `vamp:style` hints are rejected; visual styles, fonts, colors, and barline notation remain supported. Phrase cycles are written into the generated score and played once in reading order.
 
-Guitar parts share a theory-based voicing and proximity search over standard tuning, frets 0-20, and a maximum four-fret span excluding open strings. They render standard notation plus generated TAB. Practice sources provide a monophonic melody and optional chord symbols; the vocal part adds deterministic scat syllables without changing rhythm or written register. Acoustic, electric, and vocal parts all sound one octave below their notation, for both songs and practice. Explicit MusicXML instrument transposition is honored once; an unplayable passage fails rather than being shifted to fit.
+Guitar parts share a theory-based voicing and proximity search over standard tuning, frets 0-20, and a maximum four-fret span excluding open strings. Acoustic uses a bass on string 5 or 6 and two or three consecutive upper strings within 2-4, with zero or one unused string between them. Electric chords use strings 1-3 or 1-4 and may omit the root. Electric melody notes longer than a quarter note, including full tied runs, receive chords when playable; chord changes create fresh attacks even for short remaining fragments. Song electric melodies are raised one octave; practice and vocal registers stay unchanged. All parts still sound one octave below their generated notation, and explicit MusicXML transposition is honored once. Unplayable melody harmonizations remain single notes with a diagnostic; unplayable accompaniment fails generation.
+
+All parts use two music systems per page, with a single system only when the score ends on an odd system. Tall notation is scaled uniformly to fit the two rows; guitar notation and TAB stay together and aligned. TAB displays frets and ties without duplicate rests; standard notation retains the complete rhythm. The generated `.pages/*.png` files are the same page images displayed by the product.
 
 Write all music in reading order: repeat bars, numbered endings, navigation jumps, and pass-specific ties are rejected. The seven-section performance arrangements remain fully written out. Chord labels use `M`, `m`, `aug`, `dim`, `sus`, and `mM7`, including explicit major triads such as `CM`. Recognized Soundslice text-only harmonies are normalized into structured chords; parenthesized chords mark optional turnarounds omitted from the final arrangement ending.
 
@@ -121,7 +123,7 @@ Use American English in project-owned identifiers, filenames, messages, and docu
 
 See [Score Generation](TECHNICAL_GUIDE.md#score-generation) for supported MusicXML notation, Vamp properties, schema details, and diagnostics. There is no compact-JSON source format or legacy runtime adapter. Unsupported notation fails generation before existing assets are replaced.
 
-Build-time engraving is implemented in Python in `generator/engraving`, using the bundled Petaluma OTF fonts and SMuFL metadata. MuseScore is an optional authoring tool, not a build dependency or rendering backend. The managed image and CI install the pinned Python requirements automatically; direct host builds use `pip install -r generator/requirements.txt`. Exact musical timing is retained through layout, and dense measures can continue across systems without shrinking the notation. Missing glyphs, unrepresentable page geometry, and failed notation audits stop generation before replacing existing assets.
+Build-time engraving is implemented in Python in `generator/engraving`, using the bundled Petaluma OTF fonts and SMuFL metadata. MuseScore is an optional authoring tool, not a build dependency or rendering backend. The managed image and CI install the pinned Python requirements automatically; direct host builds use `pip install -r generator/requirements.txt`. Exact musical timing is retained through layout, and dense measures can continue across systems. Missing glyphs, unrepresentable page geometry, and failed notation audits stop generation before replacing existing assets.
 
 Petaluma is from Steinberg under the SIL Open Font License. Petaluma supplies music glyphs, and Petaluma Script supplies all visible text on score pages and both device interfaces. The Zero uses packaged `PetalumaScript.otf` for dynamic UI text; the Pico displays prerendered Petaluma Script artwork. Runtime packages retain `OFL.txt`; the music font and engraver stay build-only.