move volume/panning application to the main process function

this will make the next change easier

crates/kira/src/sound/static_sound/sound.rs

@@ -115,19 +115,14 @@ impl StaticSound {
 
 	/// Updates the current frame index by 1 and pushes a new sample to the resampler.
 	fn update_position(&mut self) {
-		if !self.playback_state_manager.playback_state().is_advancing() {
-			self.resampler
-				.push_frame(Frame::ZERO, self.transport.position);
-			return;
-		}
 		self.push_frame_to_resampler();
 		if self.is_playing_backwards() {
 			self.transport.decrement_position();
 		} else {
 			self.transport
 				.increment_position(num_frames(&self.frames, self.slice));
 		}
-		if !self.transport.playing && self.resampler.outputting_silence() {
+		if !self.transport.playing && self.resampler.empty() {
 			self.playback_state_manager.mark_as_stopped();
 			self.update_shared_playback_state();
 		}
@@ -145,15 +140,12 @@ impl StaticSound {
 
 	fn push_frame_to_resampler(&mut self) {
 		let frame = if self.transport.playing {
-			let frame_index: usize = self.transport.position;
-			let fade_volume = self.playback_state_manager.fade_volume().as_amplitude();
-			let volume = self.volume.value().as_amplitude();
-			(frame_at_index(frame_index, &self.frames, self.slice).unwrap_or_default()
-				* fade_volume
-				* volume)
-				.panned(self.panning.value())
+			Some(
+				frame_at_index(self.transport.position, &self.frames, self.slice)
+					.unwrap_or_default(),
+			)
 		} else {
-			Frame::ZERO
+			None
 		};
 		self.resampler.push_frame(frame, self.transport.position);
 	}
@@ -229,6 +221,11 @@ impl Sound for StaticSound {
 			return;
 		}
 
+		if !self.playback_state_manager.playback_state().is_advancing() {
+			out.fill(Frame::ZERO);
+			return;
+		}
+
 		// play back audio
 		for frame in out {
 			let out = self.resampler.get(self.fractional_position as f32);
@@ -238,7 +235,10 @@ impl Sound for StaticSound {
 				self.fractional_position -= 1.0;
 				self.update_position();
 			}
-			*frame = out;
+			*frame = (out
+				* self.playback_state_manager.fade_volume().as_amplitude()
+				* self.volume.value().as_amplitude())
+			.panned(self.panning.value());
 		}
 	}
 

crates/kira/src/sound/static_sound/sound/resampler.rs

@@ -3,7 +3,7 @@ use crate::frame::{interpolate_frame, Frame};
 #[derive(Debug, Clone, Copy, PartialEq)]
 struct RecentFrame {
 	/// A frame of audio.
-	frame: Frame,
+	frame: Option<Frame>,
 	/// The current frame index of the source sound at the
 	/// time this frame was pushed to the resampler.
 	frame_index: usize,
@@ -18,13 +18,13 @@ impl Resampler {
 	pub fn new(starting_frame_index: usize) -> Self {
 		Self {
 			frames: [RecentFrame {
-				frame: Frame::ZERO,
+				frame: None,
 				frame_index: starting_frame_index,
 			}; 4],
 		}
 	}
 
-	pub fn push_frame(&mut self, frame: Frame, sample_index: usize) {
+	pub fn push_frame(&mut self, frame: Option<Frame>, sample_index: usize) {
 		for i in 0..self.frames.len() - 1 {
 			self.frames[i] = self.frames[i + 1];
 		}
@@ -37,10 +37,10 @@ impl Resampler {
 	#[must_use]
 	pub fn get(&self, fractional_position: f32) -> Frame {
 		interpolate_frame(
-			self.frames[0].frame,
-			self.frames[1].frame,
-			self.frames[2].frame,
-			self.frames[3].frame,
+			self.frames[0].frame.unwrap_or_default(),
+			self.frames[1].frame.unwrap_or_default(),
+			self.frames[2].frame.unwrap_or_default(),
+			self.frames[3].frame.unwrap_or_default(),
 			fractional_position,
 		)
 	}
@@ -59,9 +59,9 @@ impl Resampler {
 	}
 
 	#[must_use]
-	pub fn outputting_silence(&self) -> bool {
+	pub fn empty(&self) -> bool {
 		self.frames
 			.iter()
-			.all(|RecentFrame { frame, .. }| *frame == Frame::ZERO)
+			.all(|RecentFrame { frame, .. }| frame.is_none())
 	}
 }

crates/kira/src/sound/static_sound/sound/test.rs

@@ -172,23 +172,23 @@ fn pauses_and_resumes_with_fades() {
 	);
 	assert_eq!(
 		sound.playback_state_manager.playback_state(),
-		PlaybackState::Playing
+		PlaybackState::Resuming
 	);
 	assert_eq!(
 		sound.process_one(1.0, &MockInfoBuilder::new().build()),
 		Frame::from_mono(Decibels(-30.0).as_amplitude()).panned(Panning::CENTER)
 	);
 	assert_eq!(
 		sound.playback_state_manager.playback_state(),
-		PlaybackState::Playing
+		PlaybackState::Resuming
 	);
 	assert_eq!(
 		sound.process_one(1.0, &MockInfoBuilder::new().build()),
 		Frame::from_mono(Decibels(-15.0).as_amplitude()).panned(Panning::CENTER)
 	);
 	assert_eq!(
 		sound.playback_state_manager.playback_state(),
-		PlaybackState::Playing
+		PlaybackState::Resuming
 	);
 
 	for _ in 0..3 {