[add] example which plays our slash sound.

Author: vmarcella

Cargo.lock

@@ -8,6 +8,7 @@ members = [
   "crates/lambda-rs-logging",
   "crates/lambda-rs-platform",
   "tools/obj_loader",
+  "tools/lambda_audio",
 ]
 
 default-members = [
@@ -16,4 +17,5 @@ default-members = [
   "crates/lambda-rs-logging",
   "crates/lambda-rs-platform",
   "tools/obj_loader",
+  "tools/lambda_audio",
 ]

Cargo.toml

@@ -0,0 +1,86 @@
+#![allow(clippy::needless_return)]
+
+use std::{
+  sync::{
+    atomic::{
+      AtomicUsize,
+      Ordering,
+    },
+    Arc,
+  },
+  time::Duration,
+};
+
+use lambda::audio::{
+  AudioOutputDeviceBuilder,
+  SoundBuffer,
+};
+
+#[cfg(all(
+  feature = "audio-output-device",
+  feature = "audio-sound-buffer-vorbis"
+))]
+fn main() {
+  const SLASH_VORBIS_STEREO_48000_OGG: &[u8] = include_bytes!(concat!(
+    env!("CARGO_MANIFEST_DIR"),
+    "/../lambda-rs-platform/assets/audio/slash_vorbis_stereo_48000.ogg"
+  ));
+
+  let buffer =
+    SoundBuffer::from_ogg_bytes(SLASH_VORBIS_STEREO_48000_OGG).unwrap();
+
+  let cursor = Arc::new(AtomicUsize::new(0));
+  let buffer = Arc::new(buffer);
+
+  let cursor_for_callback = cursor.clone();
+  let buffer_for_callback = buffer.clone();
+
+  let _device = AudioOutputDeviceBuilder::new()
+    .with_label("play-slash-sound")
+    .with_sample_rate(buffer.sample_rate())
+    .with_channels(buffer.channels())
+    .build_with_output_callback(move |writer, _info| {
+      let writer_channels = writer.channels() as usize;
+      let writer_frames = writer.frames();
+
+      writer.clear();
+
+      if writer_channels == 0 {
+        return;
+      }
+
+      let write_samples = writer_frames.saturating_mul(writer_channels);
+      let start =
+        cursor_for_callback.fetch_add(write_samples, Ordering::Relaxed);
+
+      let source_samples = buffer_for_callback.samples();
+
+      for frame in 0..writer_frames {
+        for channel in 0..writer_channels {
+          let sample_index = start
+            .saturating_add(frame.saturating_mul(writer_channels))
+            .saturating_add(channel);
+          let value = source_samples.get(sample_index).copied().unwrap_or(0.0);
+          writer.set_sample(frame, channel, value);
+        }
+      }
+
+      return;
+    })
+    .unwrap();
+
+  std::thread::sleep(Duration::from_secs_f32(buffer.duration_seconds() + 0.20));
+  drop(_device);
+  return;
+}
+
+#[cfg(not(all(
+  feature = "audio-output-device",
+  feature = "audio-sound-buffer-vorbis"
+)))]
+fn main() {
+  eprintln!(
+    "this example requires `audio-output-device` and `audio-sound-buffer-vorbis`"
+  );
+  return;
+}

crates/lambda-rs/examples/play_slash_sound.rs

@@ -83,6 +83,20 @@ impl SoundBuffer {
     return self.channels;
   }
 
+  /// Return interleaved `f32` samples in nominal range `[-1.0, 1.0]`.
+  pub fn samples(&self) -> &[f32] {
+    return self.samples.as_slice();
+  }
+
+  /// Return the number of frames in this buffer.
+  pub fn frames(&self) -> usize {
+    if self.channels == 0 {
+      return 0;
+    }
+
+    return self.samples.len() / self.channels as usize;
+  }
+
   pub fn duration_seconds(&self) -> f32 {
     if self.channels == 0 || self.sample_rate == 0 {
       return 0.0;

crates/lambda-rs/src/audio/buffer.rs

@@ -3,13 +3,13 @@ title: "Audio File Loading (SoundBuffer)"
 document_id: "audio-file-loading-2026-01-31"
 status: "draft"
 created: "2026-01-31T22:07:49Z"
-last_updated: "2026-01-31T23:03:17Z"
-version: "0.2.0"
+last_updated: "2026-02-02T17:40:16Z"
+version: "0.2.1"
 engine_workspace_version: "2023.1.30"
 wgpu_version: "26.0.1"
 shader_backend_default: "naga"
 winit_version: "0.29.10"
-repo_commit: "7cf8891f861a625b989f3751fd61674d072a53fe"
+repo_commit: "5d43a864febd72111671a4fab701cb0e5d2538b6"
 owners: ["lambda-sh"]
 reviewers: ["engine", "rendering"]
 tags: ["spec", "audio", "lambda-rs", "platform", "assets"]
@@ -175,6 +175,8 @@ impl SoundBuffer {
 
   pub fn sample_rate(&self) -> u32;
   pub fn channels(&self) -> u16;
+  pub fn samples(&self) -> &[f32];
+  pub fn frames(&self) -> usize;
   pub fn duration_seconds(&self) -> f32;
 }
 ```
@@ -296,7 +298,7 @@ Recommendations
 - Tests
   - [ ] Unit tests cover WAV mono and stereo
   - [ ] Unit tests cover OGG Vorbis mono and stereo
-  - [ ] Test assets are stored under `crates/lambda-rs/assets/`
+  - [ ] Test assets are stored under `crates/lambda-rs-platform/assets/audio/`
 
 For each checked item, include a reference to a commit, pull request, or file
 path that demonstrates the implementation.