Spell amiga correctly

This commit is contained in:
Gwilym Inzani 2024-05-15 21:54:31 +01:00
parent dac17ec28e
commit b5fc27d243

View file

@ -472,7 +472,7 @@ fn note_to_speed(
FrequencyType::LinearFrequencies => { FrequencyType::LinearFrequencies => {
note_to_frequency_linear(note, fine_tune, relative_note) note_to_frequency_linear(note, fine_tune, relative_note)
} }
FrequencyType::AmigaFrequencies => note_to_frequency_amega(note, fine_tune, relative_note), FrequencyType::AmigaFrequencies => note_to_frequency_amiga(note, fine_tune, relative_note),
}; };
let gba_audio_frequency = 32768f64; let gba_audio_frequency = 32768f64;
@ -487,22 +487,22 @@ fn note_to_frequency_linear(note: Note, fine_tune: f64, relative_note: i8) -> f6
8363.0 * 2.0f64.powf((6.0 * 12.0 * 16.0 * 4.0 - period) / (12.0 * 16.0 * 4.0)) 8363.0 * 2.0f64.powf((6.0 * 12.0 * 16.0 * 4.0 - period) / (12.0 * 16.0 * 4.0))
} }
fn note_to_frequency_amega(note: Note, fine_tune: f64, relative_note: i8) -> f64 { fn note_to_frequency_amiga(note: Note, fine_tune: f64, relative_note: i8) -> f64 {
let note = (note as usize) let note = (note as usize)
.checked_add_signed(relative_note as isize) .checked_add_signed(relative_note as isize)
.expect("Note gone negative"); .expect("Note gone negative");
let pos = ((note % 12) * 8 + (fine_tune / 16.0) as usize).min(AMEGA_FREQUENCIES.len() - 2); let pos = ((note % 12) * 8 + (fine_tune / 16.0) as usize).min(AMIGA_FREQUENCIES.len() - 2);
let frac = (fine_tune / 16.0) - (fine_tune / 16.0).floor(); let frac = (fine_tune / 16.0) - (fine_tune / 16.0).floor();
let period = ((AMEGA_FREQUENCIES[pos] as f64 * (1.0 - frac)) let period = ((AMIGA_FREQUENCIES[pos] as f64 * (1.0 - frac))
+ AMEGA_FREQUENCIES[pos + 1] as f64 * frac) + AMIGA_FREQUENCIES[pos + 1] as f64 * frac)
* 32.0 // docs say 16 here, but for some reason I need 32 :/ * 32.0 // docs say 16 here, but for some reason I need 32 :/
/ (1 << ((note as i64) / 12)) as f64; / (1 << ((note as i64) / 12)) as f64;
8363.0 * 1712.0 / period 8363.0 * 1712.0 / period
} }
static AMEGA_FREQUENCIES: &[u32] = &[ static AMIGA_FREQUENCIES: &[u32] = &[
907, 900, 894, 887, 881, 875, 868, 862, 856, 850, 844, 838, 832, 826, 820, 814, 808, 802, 796, 907, 900, 894, 887, 881, 875, 868, 862, 856, 850, 844, 838, 832, 826, 820, 814, 808, 802, 796,
791, 785, 779, 774, 768, 762, 757, 752, 746, 741, 736, 730, 725, 720, 715, 709, 704, 699, 694, 791, 785, 779, 774, 768, 762, 757, 752, 746, 741, 736, 730, 725, 720, 715, 709, 704, 699, 694,
689, 684, 678, 675, 670, 665, 660, 655, 651, 646, 640, 636, 632, 628, 623, 619, 614, 610, 604, 689, 684, 678, 675, 670, 665, 660, 655, 651, 646, 640, 636, 632, 628, 623, 619, 614, 610, 604,