audio: make sounds! woah

2 files changed, 29 insertions, 19 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);
diff --git a/audio/src/program.rs b/audio/src/program.rs
index cd050e3..efda90b 100644
--- a/audio/src/program.rs
+++ b/audio/src/program.rs
@@ -246,6 +246,6 @@ impl PartialOrd for Program {
 }
 impl Ord for Program {
 	fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-		other.priority.cmp(&self.priority)
+		self.priority.cmp(&other.priority)
 	}
 }