From e8cd2fc7275d0799115d6db57090c2f99d9a99a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois?= <mockersf@gmail.com>
Date: Fri, 8 Apr 2022 23:12:30 +0000
Subject: [PATCH] Audio control at start of playback (#4110)

# Objective

- While playing with volume, I noticed that when setting the volume just after playback start, I still get a few milliseconds at normal volume

## Solution

- Replace `play_in_loop` with `play_with_settings` that allows from more controls
- Adds a `PlaybackSettings` to specify the settings from start. Can be used: `PlaybackSettings::LOOP.with_volume(0.75)`
---
 crates/bevy_audio/src/audio.rs        | 79 ++++++++++++++++++++++++---
 crates/bevy_audio/src/audio_output.rs | 12 +++-
 crates/bevy_audio/src/lib.rs          |  2 +-
 3 files changed, 83 insertions(+), 10 deletions(-)

diff --git a/crates/bevy_audio/src/audio.rs b/crates/bevy_audio/src/audio.rs
index 4384175705..a7c3a614ba 100644
--- a/crates/bevy_audio/src/audio.rs
+++ b/crates/bevy_audio/src/audio.rs
@@ -78,7 +78,7 @@ where
     pub fn play(&self, audio_source: Handle<Source>) -> Handle<AudioSink> {
         let id = HandleId::random::<AudioSink>();
         let config = AudioToPlay {
-            repeat: false,
+            settings: PlaybackSettings::ONCE,
             sink_handle: id,
             source_handle: audio_source,
         };
@@ -86,13 +86,31 @@ where
         Handle::<AudioSink>::weak(id)
     }
 
-    /// Play audio from a [`Handle`] to the audio source in a loop
+    /// Play audio from a [`Handle`] to the audio source with [`PlaybackSettings`] that
+    /// allows looping or changing volume from the start.
     ///
-    /// See [`Self::play`] on how to control playback.
-    pub fn play_in_loop(&self, audio_source: Handle<Source>) -> Handle<AudioSink> {
+    /// ```
+    /// # use bevy_ecs::system::Res;
+    /// # use bevy_asset::AssetServer;
+    /// # use bevy_audio::Audio;
+    /// # use bevy_audio::PlaybackSettings;
+    /// fn play_audio_system(asset_server: Res<AssetServer>, audio: Res<Audio>) {
+    ///     audio.play_with_settings(
+    ///         asset_server.load("my_sound.ogg"),
+    ///         PlaybackSettings::LOOP.with_volume(0.75),
+    ///     );
+    /// }
+    /// ```
+    ///
+    /// See [`Self::play`] on how to control playback once it's started.
+    pub fn play_with_settings(
+        &self,
+        audio_source: Handle<Source>,
+        settings: PlaybackSettings,
+    ) -> Handle<AudioSink> {
         let id = HandleId::random::<AudioSink>();
         let config = AudioToPlay {
-            repeat: true,
+            settings,
             sink_handle: id,
             source_handle: audio_source,
         };
@@ -101,14 +119,59 @@ where
     }
 }
 
-#[derive(Clone, PartialEq, Eq)]
+/// Settings to control playback from the start.
+#[derive(Clone, Debug)]
+pub struct PlaybackSettings {
+    /// Play in repeat
+    pub repeat: bool,
+    /// Volume to play at.
+    pub volume: f32,
+    /// Speed to play at.
+    pub speed: f32,
+}
+
+impl Default for PlaybackSettings {
+    fn default() -> Self {
+        Self::ONCE
+    }
+}
+
+impl PlaybackSettings {
+    /// Will play the associate audio source once.
+    pub const ONCE: PlaybackSettings = PlaybackSettings {
+        repeat: false,
+        volume: 1.0,
+        speed: 1.0,
+    };
+
+    /// Will play the associate audio source in a loop.
+    pub const LOOP: PlaybackSettings = PlaybackSettings {
+        repeat: true,
+        volume: 1.0,
+        speed: 1.0,
+    };
+
+    /// Helper to set the volume from start of playback.
+    pub const fn with_volume(mut self, volume: f32) -> Self {
+        self.volume = volume;
+        self
+    }
+
+    /// Helper to set the speed from start of playback.
+    pub const fn with_speed(mut self, speed: f32) -> Self {
+        self.speed = speed;
+        self
+    }
+}
+
+#[derive(Clone)]
 pub(crate) struct AudioToPlay<Source>
 where
     Source: Asset + Decodable,
 {
     pub(crate) sink_handle: HandleId,
     pub(crate) source_handle: Handle<Source>,
-    pub(crate) repeat: bool,
+    pub(crate) settings: PlaybackSettings,
 }
 
 impl<Source> fmt::Debug for AudioToPlay<Source>
@@ -119,7 +182,7 @@ where
         f.debug_struct("AudioToPlay")
             .field("sink_handle", &self.sink_handle)
             .field("source_handle", &self.source_handle)
-            .field("repeat", &self.repeat)
+            .field("settings", &self.settings)
             .finish()
     }
 }
diff --git a/crates/bevy_audio/src/audio_output.rs b/crates/bevy_audio/src/audio_output.rs
index 598881a704..d0641dce7c 100644
--- a/crates/bevy_audio/src/audio_output.rs
+++ b/crates/bevy_audio/src/audio_output.rs
@@ -68,7 +68,10 @@ where
         while i < len {
             let config = queue.pop_front().unwrap();
             if let Some(audio_source) = audio_sources.get(&config.source_handle) {
-                if let Some(sink) = self.play_source(audio_source, config.repeat) {
+                if let Some(sink) = self.play_source(audio_source, config.settings.repeat) {
+                    sink.set_speed(config.settings.speed);
+                    sink.set_volume(config.settings.volume);
+
                     // don't keep the strong handle. there is no way to return it to the user here as it is async
                     let _ = sinks.set(config.sink_handle, AudioSink { sink: Some(sink) });
                 }
@@ -186,4 +189,11 @@ impl AudioSink {
     pub fn is_paused(&self) -> bool {
         self.sink.as_ref().unwrap().is_paused()
     }
+
+    /// Stops the sink.
+    ///
+    /// It won't be possible to restart it afterwards.
+    pub fn stop(&self) {
+        self.sink.as_ref().unwrap().stop();
+    }
 }
diff --git a/crates/bevy_audio/src/lib.rs b/crates/bevy_audio/src/lib.rs
index fc48a19013..5aa23f7aa5 100644
--- a/crates/bevy_audio/src/lib.rs
+++ b/crates/bevy_audio/src/lib.rs
@@ -35,7 +35,7 @@ mod audio_source;
 #[allow(missing_docs)]
 pub mod prelude {
     #[doc(hidden)]
-    pub use crate::{Audio, AudioOutput, AudioSource, Decodable};
+    pub use crate::{Audio, AudioOutput, AudioSource, Decodable, PlaybackSettings};
 }
 
 pub use audio::*;