[update] audio to be an optional feature and create separate matrices for testing audio out (Will make a headless/game feature set to group certain features together in the future)

Author: vmarcella

.github/workflows/compile_lambda_rs.yml

@@ -23,12 +23,21 @@ jobs:
           - os: ubuntu-latest
             rustup-toolchain: "stable"
             features: "lambda-rs/with-vulkan"
+          - os: ubuntu-latest
+            rustup-toolchain: "stable"
+            features: "lambda-rs/with-vulkan,lambda-rs/audio-output-device"
           - os: windows-latest
             rustup-toolchain: "stable"
             features: "lambda-rs/with-dx12"
+          - os: windows-latest
+            rustup-toolchain: "stable"
+            features: "lambda-rs/with-dx12,lambda-rs/audio-output-device"
           - os: macos-latest
             rustup-toolchain: "stable"
             features: "lambda-rs/with-metal"
+          - os: macos-latest
+            rustup-toolchain: "stable"
+            features: "lambda-rs/with-metal,lambda-rs/audio-output-device"
 
     steps:
       - name: Checkout Repository
@@ -48,9 +57,15 @@ jobs:
             pkg-config libx11-dev libxcb1-dev libxcb-render0-dev \
             libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev \
             libwayland-dev libudev-dev \
-            libasound2-dev \
             libvulkan-dev libvulkan1 mesa-vulkan-drivers vulkan-tools
 
+      - name: Install Linux deps for audio
+        if: ${{ matrix.os == 'ubuntu-latest' && contains(matrix.features, 'lambda-rs/audio-output-device') }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            libasound2-dev
+
       - name: Configure Vulkan (Ubuntu)
         if: ${{ matrix.os == 'ubuntu-latest' }}
         run: |

crates/lambda-rs/Cargo.toml

@@ -20,7 +20,7 @@ cargo-audit = "0.16.0"
 mockall = "0.14.0"
 
 [features]
-default=["with-wgpu", "audio"]
+default=["with-wgpu"]
 with-vulkan=["with-wgpu", "lambda-rs-platform/wgpu-with-vulkan"]
 with-opengl=["with-wgpu", "lambda-rs-platform/wgpu-with-gl"]
 with-dx11=["with-wgpu"]

docs/features.md

@@ -3,13 +3,13 @@ title: "Cargo Features Overview"
 document_id: "features-2025-11-17"
 status: "living"
 created: "2025-11-17T23:59:00Z"
-last_updated: "2026-01-30T23:40:49Z"
-version: "0.1.10"
+last_updated: "2026-01-31T00:00:27Z"
+version: "0.1.11"
 engine_workspace_version: "2023.1.30"
 wgpu_version: "26.0.1"
 shader_backend_default: "naga"
 winit_version: "0.29.10"
-repo_commit: "df62c624ca869e0493a3a92297d1cebe94251e69"
+repo_commit: "2ae6419f001550adaa13a387b94fdf2bd86a882b"
 owners: ["lambda-sh"]
 reviewers: ["engine", "rendering"]
 tags: ["guide", "features", "validation", "cargo", "audio"]
@@ -31,11 +31,12 @@ relationships, and expected behavior in debug and release builds.
 - Workspace defaults prefer `wgpu` on supported platforms and `naga` for shader compilation.
 - Debug builds enable all validations unconditionally via `debug_assertions`.
 - Release builds enable only cheap safety checks by default; validation logs and per-draw checks MUST be enabled explicitly via features.
-- Audio support in `lambda-rs` is enabled by default and incurs runtime cost
-  only when an audio device is initialized and kept alive.
-  - Linux builds that include the default audio backend MUST provide ALSA
-    development headers and `pkg-config` (for example, `libasound2-dev` on
-    Debian/Ubuntu).
+- Audio support in `lambda-rs` is opt-in (disabled by default) and incurs
+  runtime cost only when an audio device is initialized and kept alive.
+  - Linux builds that enable audio output devices MUST provide ALSA development
+    headers and `pkg-config` (for example, `libasound2-dev` on Debian/Ubuntu).
+- To minimize dependencies in headless or minimal environments, prefer
+  `--no-default-features` and enable only the required features explicitly.
 
 ## lambda-rs
 
@@ -59,9 +60,9 @@ Rendering backends
   - `with-dx11`: alias for `with-wgpu`.
 
 Audio
-- `audio` (umbrella, enabled by default): enables audio support by composing
+- `audio` (umbrella, disabled by default): enables audio support by composing
   granular audio features. This umbrella includes `audio-output-device`.
-- `audio-output-device` (granular, enabled by default): enables audio output
+- `audio-output-device` (granular, disabled by default): enables audio output
   device enumeration and callback-based audio output via `lambda::audio`. This
   feature enables `lambda-rs-platform/audio-device` internally. Expected
   runtime cost is proportional to the output callback workload and buffer size;
@@ -135,6 +136,7 @@ Audio
   backend module `lambda_platform::cpal` backed by `cpal =0.17.1`.
 
 ## Changelog
+- 0.1.11 (2026-01-30): Make `lambda-rs` audio features opt-in by default.
 - 0.1.10 (2026-01-30): Document Linux system dependencies required by the
   default audio backend.
 - 0.1.9 (2026-01-30): Clarify workspace default audio behavior after enabling

docs/specs/audio-devices.md

@@ -3,13 +3,13 @@ title: "Audio Device Abstraction"
 document_id: "audio-device-abstraction-2026-01-28"
 status: "draft"
 created: "2026-01-28T22:59:00Z"
-last_updated: "2026-01-30T23:40:49Z"
-version: "0.1.13"
+last_updated: "2026-01-31T00:00:27Z"
+version: "0.1.15"
 engine_workspace_version: "2023.1.30"
 wgpu_version: "26.0.1"
 shader_backend_default: "naga"
 winit_version: "0.29.10"
-repo_commit: "df62c624ca869e0493a3a92297d1cebe94251e69"
+repo_commit: "2ae6419f001550adaa13a387b94fdf2bd86a882b"
 owners: ["lambda-sh"]
 reviewers: ["engine", "rendering"]
 tags: ["spec", "audio", "lambda-rs", "platform", "cpal"]
@@ -326,10 +326,10 @@ Implementation rules
 
 Features
 
-- `lambda-rs` granular feature: `audio-output-device` (default: enabled)
+- `lambda-rs` granular feature: `audio-output-device` (default: disabled)
   - Enables the `lambda::audio` output device surface.
   - Enables `lambda-rs-platform` `audio-device` internally.
-- `lambda-rs` umbrella feature: `audio` (default: enabled)
+- `lambda-rs` umbrella feature: `audio` (default: disabled)
   - Composes `audio-output-device` only.
 
 ### Application Interaction
@@ -522,10 +522,10 @@ Validation rules
 Features introduced by this spec
 
 - Crate: `lambda-rs`
-  - Granular feature: `audio-output-device` (default: enabled)
+  - Granular feature: `audio-output-device` (default: disabled)
     - Enables `lambda::audio` output device APIs.
     - Enables `lambda-rs-platform` `audio-device` internally.
-  - Umbrella feature: `audio` (default: enabled)
+  - Umbrella feature: `audio` (default: disabled)
     - Composes `audio-output-device` only.
 - Crate: `lambda-rs-platform`
   - Granular feature: `audio-device` (default: disabled)
@@ -625,7 +625,7 @@ Example (lambda-rs facade)
 This example is the primary application-facing reference.
 
 - Add `crates/lambda-rs/examples/audio_sine_wave.rs` (feature:
-  `audio-output-device`, enabled by default) that:
+  `audio-output-device`, disabled by default) that:
   - Prints `lambda::audio::enumerate_output_devices()` output.
   - Builds the default output device via the facade builder and plays a
     deterministic 440 Hz tone for at least 2 seconds.
@@ -648,14 +648,18 @@ Manual checks
 
 - Run the `lambda-rs` facade example and confirm audible playback for at least
   2 seconds.
-  - `cargo run -p lambda-rs --example audio_sine_wave`
+  - `cargo run -p lambda-rs --example audio_sine_wave --features audio-output-device`
 
 ## Compatibility and Migration
 
 - None. No existing audio APIs exist in the workspace.
 
 ## Changelog
 
+- 2026-01-31 (v0.1.15) — Update verification command to include
+  `audio-output-device`.
+- 2026-01-30 (v0.1.14) — Make `lambda-rs` audio features opt-in by default and
+  update CI to test Linux audio builds explicitly.
 - 2026-01-30 (v0.1.13) — Document Linux system dependencies required by the
   default audio backend.
 - 2026-01-30 (v0.1.12) — Populate the requirements checklist with file