khodowany
56 lines
1.9 KiB
Python
56 lines
1.9 KiB
Python
"""Sounding-register references and hard solo instrument domains."""
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from __future__ import annotations
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import dataclasses
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from fractions import Fraction as F
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import generator.fretboard
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@dataclasses.dataclass(frozen=True)
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class Instrument:
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part: str = ''
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strings: tuple[int, ...] = (1, 2, 3, 4, 5, 6)
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reference: int | None = None
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melody_range: tuple[int, int] | None = None
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@property
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def register(self):
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tuning = [p for s, p in generator.fretboard.STANDARD_TUNING if s in self.strings]
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return min(tuning) + 1, max(tuning) + 12
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def permits(self, number):
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return any(p.string_number in self.strings for p in generator.fretboard.single_positions_for_pitch(F(number)))
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def cost(self, number):
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return min(1., max(0, abs(number - self.reference) - 4) / 12) if self.reference is not None else 0.
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UNRESTRICTED = Instrument()
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def weighted_center(notes):
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values = sorted((n.pitch.number(), n.end - n.start) for n in notes)
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total = sum((d for _, d in values), F())
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elapsed = F()
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for number, duration in values:
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elapsed += duration
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if elapsed >= total / 2:
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return number
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return 60
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def for_part(part, analysis=None):
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if part not in ('acoustic', 'electric'):
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raise ValueError('unknown solo instrument: ' + part)
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strings = (2, 3, 4, 5, 6) if part == 'acoustic' else (1, 2, 3, 4)
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if analysis is None or not analysis.melody:
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return Instrument(part, strings)
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# Analysis contains the prepared concert source. Electric melody is written
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# two octaves up and sounds one down (parts.build_measure), hence +12.
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# Use the source voice, never the highest added harmonization voice.
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shift = 12 if part == 'electric' else 0
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notes = tuple(n for n in analysis.melody if n.end > analysis.body_offset)
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return Instrument(part, strings, weighted_center(notes) + shift,
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(min(n.pitch.number() for n in notes) + shift, max(n.pitch.number() for n in notes) + shift))
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