Merge pull request #523 from alexmoon/examples

Examples improvements

Author: est31

.github/workflows/cpal.yml

@@ -262,6 +262,8 @@ jobs:
         toolchain: stable
         override: true
         target: armv7-linux-androideabi
+    - name: Check android
+      run: cargo check --example android --target armv7-linux-androideabi --verbose
     - name: Check beep
       run: cargo check --example beep --target armv7-linux-androideabi --verbose
     - name: Check enumerate
@@ -284,4 +286,4 @@ jobs:
     - name: Install Cargo APK
       run: cargo install cargo-apk
     - name: Build APK
-      run: cargo apk build --example beep
+      run: cargo apk build --example android

Cargo.toml

@@ -18,6 +18,7 @@ thiserror = "1.0.2"
 anyhow = "1.0.12"
 hound = "3.4"
 ringbuf = "0.2"
+clap = { version = "2.33.3", default-features = false }
 
 [target.'cfg(target_os = "windows")'.dependencies]
 winapi = { version = "0.3", features = ["audiosessiontypes", "audioclient", "coml2api", "combaseapi", "debug", "devpkey", "handleapi", "ksmedia", "mmdeviceapi", "objbase", "profileapi", "std", "synchapi", "winbase", "winuser"] }
@@ -53,21 +54,18 @@ ndk-glue = "0.2"
 jni = "0.17"
 
 [[example]]
-name = "beep"
-path = "examples/beep.rs"
+name = "android"
+path = "examples/android.rs"
 crate-type = ["cdylib"]
 
+[[example]]
+name = "beep"
+
 [[example]]
 name = "enumerate"
-path = "examples/enumerate.rs"
-crate-type = ["cdylib"]
 
 [[example]]
 name = "feedback"
-path = "examples/feedback.rs"
-crate-type = ["cdylib"]
 
 [[example]]
 name = "record_wav"
-path = "examples/record_wav.rs"
-crate-type = ["cdylib"]

examples/android.rs

@@ -0,0 +1,65 @@
+#![allow(dead_code)]
+
+extern crate anyhow;
+extern crate cpal;
+
+use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+
+#[cfg_attr(target_os = "android", ndk_glue::main(backtrace = "full"))]
+fn main() {
+    let host = cpal::default_host();
+
+    let device = host
+        .default_output_device()
+        .expect("failed to find output device");
+
+    let config = device.default_output_config().unwrap();
+
+    match config.sample_format() {
+        cpal::SampleFormat::F32 => run::<f32>(&device, &config.into()).unwrap(),
+        cpal::SampleFormat::I16 => run::<i16>(&device, &config.into()).unwrap(),
+        cpal::SampleFormat::U16 => run::<u16>(&device, &config.into()).unwrap(),
+    }
+}
+
+fn run<T>(device: &cpal::Device, config: &cpal::StreamConfig) -> Result<(), anyhow::Error>
+where
+    T: cpal::Sample,
+{
+    let sample_rate = config.sample_rate.0 as f32;
+    let channels = config.channels as usize;
+
+    // Produce a sinusoid of maximum amplitude.
+    let mut sample_clock = 0f32;
+    let mut next_value = move || {
+        sample_clock = (sample_clock + 1.0) % sample_rate;
+        (sample_clock * 440.0 * 2.0 * std::f32::consts::PI / sample_rate).sin()
+    };
+
+    let err_fn = |err| eprintln!("an error occurred on stream: {}", err);
+
+    let stream = device.build_output_stream(
+        config,
+        move |data: &mut [T], _: &cpal::OutputCallbackInfo| {
+            write_data(data, channels, &mut next_value)
+        },
+        err_fn,
+    )?;
+    stream.play()?;
+
+    std::thread::sleep(std::time::Duration::from_millis(1000));
+
+    Ok(())
+}
+
+fn write_data<T>(output: &mut [T], channels: usize, next_sample: &mut dyn FnMut() -> f32)
+where
+    T: cpal::Sample,
+{
+    for frame in output.chunks_mut(channels) {
+        let value: T = cpal::Sample::from::<f32>(&next_sample());
+        for sample in frame.iter_mut() {
+            *sample = value;
+        }
+    }
+}

examples/beep.rs

@@ -1,21 +1,59 @@
 extern crate anyhow;
+extern crate clap;
 extern crate cpal;
 
 use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
 
-#[cfg_attr(target_os = "android", ndk_glue::main(backtrace = "full"))]
-fn main() {
+#[derive(Debug)]
+struct Opt {
+    #[cfg(all(
+        any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd"),
+        feature = "jack"
+    ))]
+    jack: bool,
+
+    device: String,
+}
+
+impl Opt {
+    fn from_args() -> Self {
+        let app = clap::App::new("beep").arg_from_usage("[DEVICE] 'The audio device to use'");
+        #[cfg(all(
+            any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd"),
+            feature = "jack"
+        ))]
+        let app = app.arg_from_usage("-j, --jack 'Use the JACK host");
+        let matches = app.get_matches();
+        let device = matches.value_of("DEVICE").unwrap_or("default").to_string();
+
+        #[cfg(all(
+            any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd"),
+            feature = "jack"
+        ))]
+        return Opt {
+            jack: matches.is_present("jack"),
+            device,
+        };
+
+        #[cfg(any(
+            not(any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd")),
+            not(feature = "jack")
+        ))]
+        Opt { device }
+    }
+}
+
+fn main() -> anyhow::Result<()> {
+    let opt = Opt::from_args();
+
     // Conditionally compile with jack if the feature is specified.
     #[cfg(all(
         any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd"),
         feature = "jack"
     ))]
     // Manually check for flags. Can be passed through cargo with -- e.g.
     // cargo run --release --example beep --features jack -- --jack
-    let host = if std::env::args()
-        .collect::<String>()
-        .contains(&String::from("--jack"))
-    {
+    let host = if opt.jack {
         cpal::host_from_id(cpal::available_hosts()
             .into_iter()
             .find(|id| *id == cpal::HostId::Jack)
@@ -32,19 +70,26 @@ fn main() {
     ))]
     let host = cpal::default_host();
 
-    let device = host
-        .default_output_device()
-        .expect("failed to find a default output device");
+    let device = if opt.device == "default" {
+        host.default_output_device()
+    } else {
+        host.output_devices()?
+            .find(|x| x.name().map(|y| y == opt.device).unwrap_or(false))
+    }
+    .expect("failed to find output device");
+    println!("Output device: {}", device.name()?);
+
     let config = device.default_output_config().unwrap();
+    println!("Default output config: {:?}", config);
 
     match config.sample_format() {
-        cpal::SampleFormat::F32 => run::<f32>(&device, &config.into()).unwrap(),
-        cpal::SampleFormat::I16 => run::<i16>(&device, &config.into()).unwrap(),
-        cpal::SampleFormat::U16 => run::<u16>(&device, &config.into()).unwrap(),
+        cpal::SampleFormat::F32 => run::<f32>(&device, &config.into()),
+        cpal::SampleFormat::I16 => run::<i16>(&device, &config.into()),
+        cpal::SampleFormat::U16 => run::<u16>(&device, &config.into()),
     }
 }
 
-fn run<T>(device: &cpal::Device, config: &cpal::StreamConfig) -> Result<(), anyhow::Error>
+pub fn run<T>(device: &cpal::Device, config: &cpal::StreamConfig) -> Result<(), anyhow::Error>
 where
     T: cpal::Sample,
 {
@@ -55,7 +100,7 @@ where
     let mut sample_clock = 0f32;
     let mut next_value = move || {
         sample_clock = (sample_clock + 1.0) % sample_rate;
-        (sample_clock * 440.0 * 2.0 * 3.141592 / sample_rate).sin()
+        (sample_clock * 440.0 * 2.0 * std::f32::consts::PI / sample_rate).sin()
     };
 
     let err_fn = |err| eprintln!("an error occurred on stream: {}", err);

examples/enumerate.rs

@@ -26,16 +26,16 @@ fn main() -> Result<(), anyhow::Error> {
             if let Ok(conf) = device.default_input_config() {
                 println!("    Default input stream config:\n      {:?}", conf);
             }
-            let mut input_configs = match device.supported_input_configs() {
-                Ok(f) => f.peekable(),
+            let input_configs = match device.supported_input_configs() {
+                Ok(f) => f.collect(),
                 Err(e) => {
-                    println!("Error: {:?}", e);
-                    continue;
+                    println!("    Error getting supported input configs: {:?}", e);
+                    Vec::new()
                 }
             };
-            if input_configs.peek().is_some() {
+            if !input_configs.is_empty() {
                 println!("    All supported input stream configs:");
-                for (config_index, config) in input_configs.enumerate() {
+                for (config_index, config) in input_configs.into_iter().enumerate() {
                     println!(
                         "      {}.{}. {:?}",
                         device_index + 1,
@@ -49,16 +49,16 @@ fn main() -> Result<(), anyhow::Error> {
             if let Ok(conf) = device.default_output_config() {
                 println!("    Default output stream config:\n      {:?}", conf);
             }
-            let mut output_configs = match device.supported_output_configs() {
-                Ok(f) => f.peekable(),
+            let output_configs = match device.supported_output_configs() {
+                Ok(f) => f.collect(),
                 Err(e) => {
-                    println!("Error: {:?}", e);
-                    continue;
+                    println!("    Error getting supported output configs: {:?}", e);
+                    Vec::new()
                 }
             };
-            if output_configs.peek().is_some() {
+            if !output_configs.is_empty() {
                 println!("    All supported output stream configs:");
-                for (config_index, config) in output_configs.enumerate() {
+                for (config_index, config) in output_configs.into_iter().enumerate() {
                     println!(
                         "      {}.{}. {:?}",
                         device_index + 1,