diff options
Diffstat (limited to 'audio/src/channel.rs')
| -rw-r--r-- | audio/src/channel.rs | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/audio/src/channel.rs b/audio/src/channel.rs index b74792e..2b4be02 100644 --- a/audio/src/channel.rs +++ b/audio/src/channel.rs @@ -44,7 +44,21 @@ impl ChannelKind { Self::Noise { mode: false } } - fn sample(self, phase: f32, lsr_ptr: &mut i16) -> i16 { + const fn on_phase(self, lsr_ptr: &mut i16) { + if let Self::Noise { mode } = self { + let mut lsr = *lsr_ptr; + let feedback = if mode { + (lsr & 1) ^ ((lsr >> 1) & 1) + } else { + (lsr & 1) ^ ((lsr >> 6) & 1) + }; + lsr >>= 1; + lsr |= feedback << 14; + *lsr_ptr = lsr; + } + } + + fn sample(self, phase: f32, lsr: i16) -> i16 { match self { Self::Pulse { duty_cycle } => { let duty = duty_cycle as f32 / 100.0; @@ -57,17 +71,12 @@ impl ChannelKind { let value = ((step as f32 / (steps - 1) as f32) * 4.0) - 1.0; (value * i16::MAX as f32) as i16 } - Self::Noise { mode } => { - let mut lsr = *lsr_ptr; - let feedback = if mode { - (lsr & 1) ^ ((lsr >> 1) & 1) + Self::Noise { .. } => { + if (lsr & 0x1) == 1 { + i16::MAX } else { - (lsr & 1) ^ ((lsr >> 6) & 1) - }; - lsr >>= 1; - lsr |= feedback << 14; - *lsr_ptr = lsr; - lsr + i16::MIN + } } } } @@ -98,8 +107,9 @@ impl Channel { phase += step; if phase >= 1.0 { phase -= 1.0; + self.kind.on_phase(lsr_ptr); } - let real_note = self.kind.sample(phase, lsr_ptr); + let real_note = self.kind.sample(phase, *lsr_ptr); let note = (real_note as f32 * volume) as i16; *sample += note / 4; } @@ -113,7 +123,7 @@ struct RuntimeState { pulse_b_phase: f32, triangle_phase: f32, noise_phase: f32, - noise_lsfr: i16, + noise_lsr: i16, } impl RuntimeState { const fn new() -> Self { @@ -122,7 +132,7 @@ impl RuntimeState { pulse_b_phase: 0.0, triangle_phase: 0.0, noise_phase: 0.0, - noise_lsfr: 1, + noise_lsr: 1, } } } @@ -170,13 +180,13 @@ impl<'s> Device<'s> { set_audio_stream_callback(&stream, move |buffer| { let chan = cb_data.load(Ordering::Relaxed); chan.pulse_a - .sample(buffer, &mut state.pulse_a_phase, &mut state.noise_lsfr); + .sample(buffer, &mut state.pulse_a_phase, &mut state.noise_lsr); chan.pulse_b - .sample(buffer, &mut state.pulse_b_phase, &mut state.noise_lsfr); + .sample(buffer, &mut state.pulse_b_phase, &mut state.noise_lsr); chan.triangle - .sample(buffer, &mut state.triangle_phase, &mut state.noise_lsfr); + .sample(buffer, &mut state.triangle_phase, &mut state.noise_lsr); chan.noise - .sample(buffer, &mut state.noise_phase, &mut state.noise_lsfr); + .sample(buffer, &mut state.noise_phase, &mut state.noise_lsr); })?; stream.set_volume(1.0); stream.set_pitch(1.0); |