| """Difficulty constraints — enforce per-difficulty fret and chord rules.""" |
|
|
| from midmid.datatypes import NoteEvent |
|
|
| ALLOWED_FRETS = { |
| "easy": {0, 1, 2}, |
| "medium": {0, 1, 2, 3}, |
| "hard": {0, 1, 2, 3, 4}, |
| "expert": {0, 1, 2, 3, 4}, |
| } |
|
|
| MAX_CHORD_SIZE = { |
| "easy": 1, |
| "medium": 2, |
| "hard": 3, |
| "expert": 5, |
| } |
|
|
| MIN_NOTE_SPACING = { |
| "easy": 192, |
| "medium": 96, |
| "hard": 48, |
| "expert": 0, |
| } |
|
|
|
|
| def enforce_constraints( |
| notes: list[NoteEvent], difficulty: str, resolution: int = 192, |
| ) -> list[NoteEvent]: |
| allowed = ALLOWED_FRETS.get(difficulty, {0, 1, 2, 3, 4}) |
| max_chord = MAX_CHORD_SIZE.get(difficulty, 5) |
| min_spacing = MIN_NOTE_SPACING.get(difficulty, 0) |
|
|
| result = [] |
| for note in notes: |
| filtered = note.fret_set & allowed |
| if not filtered: |
| for fret in sorted(note.fret_set): |
| closest = min(allowed, key=lambda a: abs(a - fret)) |
| filtered.add(closest) |
| break |
| if not filtered: |
| continue |
|
|
| if len(filtered) > max_chord: |
| filtered = set(sorted(filtered)[:max_chord]) |
|
|
| if min_spacing > 0 and result: |
| if note.tick - result[-1].tick < min_spacing: |
| continue |
|
|
| if result and result[-1].sustain_ticks > 0: |
| prev_end = result[-1].tick + result[-1].sustain_ticks |
| if note.tick < prev_end: |
| continue |
|
|
| result.append(NoteEvent( |
| tick=note.tick, |
| fret_set=filtered, |
| sustain_ticks=note.sustain_ticks, |
| is_hopo=note.is_hopo, |
| )) |
|
|
| sixteenth = resolution // 4 |
| if len(result) >= 2 and result[-2].sustain_ticks > 0: |
| prev = result[-2] |
| max_sustain = note.tick - prev.tick - sixteenth |
| max_sustain = (max_sustain // sixteenth) * sixteenth |
| if max_sustain < sixteenth: |
| max_sustain = 0 |
| if prev.sustain_ticks > max_sustain: |
| result[-2] = NoteEvent( |
| tick=prev.tick, |
| fret_set=prev.fret_set, |
| sustain_ticks=max_sustain, |
| is_hopo=prev.is_hopo, |
| ) |
|
|
| return result |
|
|
