desktop: Move cpal audio backend to frontend-utils

Cargo.toml

@@ -52,6 +52,7 @@ naga = { version = "22.1.0", features = ["wgsl-out"] }
 wgpu = "22.1.0"
 egui = { git = "https://github.com/emilk/egui.git", rev = "f4697bc007447c6c2674beb4e25f599fb7afa093" }
 clap = { version = "4.5.17", features = ["derive"] }
+cpal = "0.15.3"
 anyhow = "1.0"
 slotmap = "1.0.7"
 async-channel = "2.3.1"

desktop/Cargo.toml

@@ -12,7 +12,7 @@ workspace = true
 
 [dependencies]
 clap = { workspace = true }
-cpal = "0.15.3"
+cpal = { workspace = true }
 egui = { workspace = true }
 egui_extras = { git = "https://github.com/emilk/egui.git", rev = "f4697bc007447c6c2674beb4e25f599fb7afa093", default-features = false, features = ["image"] }
 egui-wgpu = { git = "https://github.com/emilk/egui.git", rev = "f4697bc007447c6c2674beb4e25f599fb7afa093", features = ["winit"] }
@@ -24,7 +24,7 @@ ruffle_render = { path = "../render", features = ["clap"] }
 ruffle_render_wgpu = { path = "../render/wgpu", features = ["clap"] }
 ruffle_video_software = { path = "../video/software", optional = true }
 ruffle_video_external = { path = "../video/external", optional = true }
-ruffle_frontend_utils = { path = "../frontend-utils" }
+ruffle_frontend_utils = { path = "../frontend-utils", features = ["cpal"] }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 tracing-appender = "0.2.3"

desktop/src/backends.rs

@@ -1,10 +1,8 @@
-mod audio;
 mod external_interface;
 mod fscommand;
 mod navigator;
 mod ui;
 
-pub use audio::CpalAudioBackend;
 pub use external_interface::DesktopExternalInterfaceProvider;
 pub use fscommand::DesktopFSCommandProvider;
 pub use navigator::DesktopNavigatorInterface;

desktop/src/player.rs

@@ -1,6 +1,6 @@
 use crate::backends::{
-    CpalAudioBackend, DesktopExternalInterfaceProvider, DesktopFSCommandProvider,
-    DesktopNavigatorInterface, DesktopUiBackend,
+    DesktopExternalInterfaceProvider, DesktopFSCommandProvider, DesktopNavigatorInterface,
+    DesktopUiBackend,
 };
 use crate::custom_event::RuffleEvent;
 use crate::gui::{FilePicker, MovieView};
@@ -11,6 +11,7 @@ use ruffle_core::backend::navigator::{OpenURLMode, SocketMode};
 use ruffle_core::config::Letterbox;
 use ruffle_core::events::{GamepadButton, KeyCode};
 use ruffle_core::{DefaultFont, LoadBehavior, Player, PlayerBuilder, PlayerEvent};
+use ruffle_frontend_utils::backends::audio::CpalAudioBackend;
 use ruffle_frontend_utils::backends::executor::{AsyncExecutor, PollRequester};
 use ruffle_frontend_utils::backends::navigator::ExternalNavigatorBackend;
 use ruffle_frontend_utils::bundle::source::BundleSourceError;
@@ -134,7 +135,7 @@ impl ActivePlayer {
     ) -> Self {
         let mut builder = PlayerBuilder::new();
 
-        match CpalAudioBackend::new(&preferences) {
+        match CpalAudioBackend::new(preferences.output_device_name().as_deref()) {
             Ok(audio) => {
                 builder = builder.with_audio(audio);
             }

frontend-utils/Cargo.toml

@@ -10,21 +10,32 @@ version.workspace = true
 [lints]
 workspace = true
 
+[features]
+cpal = ["dep:cpal", "dep:bytemuck"]
+
 [dependencies]
 toml_edit = { version = "0.22.20", features = ["parse"] }
 url = { workspace = true }
 tracing = { workspace = true }
 thiserror = { workspace = true }
-zip = { version = "2.2.0", default-features = false, features = ["deflate"]}
+zip = { version = "2.2.0", default-features = false, features = ["deflate"] }
 urlencoding = "2.1.3"
 ruffle_core = { path = "../core", default-features = false }
 ruffle_render = { path = "../render", default-features = false }
 async-channel = { workspace = true }
 slotmap = { workspace = true }
 async-io = "2.3.4"
 futures-lite = "2.3.0"
-reqwest = { version = "0.12.7", default-features = false, features = ["rustls-tls", "cookies", "charset", "http2", "macos-system-configuration"] }
+reqwest = { version = "0.12.7", default-features = false, features = [
+    "rustls-tls",
+    "cookies",
+    "charset",
+    "http2",
+    "macos-system-configuration",
+] }
 tokio = { workspace = true, features = ["net"] }
+cpal = { workspace = true, optional = true }
+bytemuck = { workspace = true, optional = true }
 
 [dev-dependencies]
 tempfile = "3"

frontend-utils/src/backends.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "cpal")]
+pub mod audio;
 pub mod executor;
 pub mod navigator;
 pub mod storage;

desktop/src/backends/audio.rs → frontend-utils/src/backends/audio.rs

@@ -1,12 +1,29 @@
-use crate::preferences::GlobalPreferences;
-use anyhow::{anyhow, Context, Error};
 use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use cpal::SampleFormat;
 use ruffle_core::backend::audio::{
     swf, AudioBackend, AudioMixer, DecodeError, RegisterError, SoundHandle, SoundInstanceHandle,
     SoundStreamInfo, SoundTransform,
 };
 use ruffle_core::impl_audio_mixer_backend;
 
+#[derive(Debug, thiserror::Error)]
+pub enum CpalError {
+    #[error("No audio devices available")]
+    NoDevices,
+
+    #[error("Failed to get default output config")]
+    DefaultStream(#[from] cpal::DefaultStreamConfigError),
+
+    #[error("Unsupported sample format {0:?}")]
+    UnsupportedSampleFormat(SampleFormat),
+
+    #[error("Couldn't play the audio stream")]
+    Play(#[from] cpal::PlayStreamError),
+
+    #[error("Failed to construct audio stream")]
+    Build(#[from] cpal::BuildStreamError),
+}
+
 pub struct CpalAudioBackend {
     #[allow(dead_code)]
     device: cpal::Device,
@@ -17,16 +34,16 @@ pub struct CpalAudioBackend {
 }
 
 impl CpalAudioBackend {
-    pub fn new(preferences: &GlobalPreferences) -> Result<Self, Error> {
+    pub fn new(preferred_device_name: Option<&str>) -> Result<Self, CpalError> {
         // Create CPAL audio device.
         let host = cpal::default_host();
-        let device = get_suitable_output_device(preferences, &host)
-            .ok_or_else(|| anyhow!("No audio devices available"))?;
+        let device =
+            get_suitable_output_device(preferred_device_name, &host).ok_or(CpalError::NoDevices)?;
 
         // Create audio stream for device.
         let config = device
             .default_output_config()
-            .context("Failed to get default output config")?;
+            .map_err(CpalError::DefaultStream)?;
         let sample_format = config.sample_format();
         let config = cpal::StreamConfig::from(config);
         let mixer = AudioMixer::new(config.channels as u8, config.sample_rate.0);
@@ -63,11 +80,11 @@ impl CpalAudioBackend {
                     error_handler,
                     None,
                 ),
-                _ => anyhow::bail!("Unsupported sample format {sample_format:?}"),
+                _ => return Err(CpalError::UnsupportedSampleFormat(sample_format)),
             }?
         };
 
-        stream.play().context("Couldn't play the audio stream")?;
+        stream.play().map_err(CpalError::Play)?;
 
         Ok(Self {
             device,
@@ -91,14 +108,14 @@ impl AudioBackend for CpalAudioBackend {
 }
 
 fn get_suitable_output_device(
-    preferences: &GlobalPreferences,
+    preferred_device_name: Option<&str>,
     host: &cpal::Host,
 ) -> Option<cpal::Device> {
     // First let's check for any user preference...
-    if let Some(preferred_device_name) = preferences.output_device_name() {
+    if let Some(preferred_device_name) = preferred_device_name {
         if let Ok(mut devices) = host.output_devices() {
             if let Some(device) =
-                devices.find(|device| device.name().ok().as_deref() == Some(&preferred_device_name))
+                devices.find(|device| device.name().ok().as_deref() == Some(preferred_device_name))
             {
                 return Some(device);
             }