feat: add non-cgo linux pulseaudio driver

.github/workflows/test.yml

@@ -61,6 +61,9 @@ jobs:
           env GOOS=darwin GOARCH=amd64 go build -v ./...
           env GOOS=darwin GOARCH=arm64 go build -v ./...
 
+          # Check cross-compiling Linux binaries.
+          env GOOS=linux GOARCH=amd64 go build -v ./...
+          env GOOS=linux GOARCH=arm64 go build -v ./...
       - name: go mod vendor
         run: |
           mkdir /tmp/vendoring

README.md

@@ -10,8 +10,7 @@ A low-level library to play sound.
   - [Prerequisite](#prerequisite)
     - [macOS](#macos)
     - [iOS](#ios)
-    - [Linux](#linux)
-    - [FreeBSD, OpenBSD](#freebsd-openbsd)
+    - [Linux, FreeBSD, OpenBSD](#linux-freebsd-openbsd)
   - [Usage](#usage)
     - [Playing sounds from memory](#playing-sounds-from-memory)
     - [Playing sounds by file streaming](#playing-sounds-by-file-streaming)
@@ -20,14 +19,14 @@ A low-level library to play sound.
 
 ## Platforms
 
-- Windows (no Cgo required!)
-- macOS (no Cgo required!)
-- Linux
-- FreeBSD
-- OpenBSD
+- Windows (no Cgo required)
+- macOS (no Cgo required)
+- Linux (no Cgo required)
+- FreeBSD (no Cgo required)
+- OpenBSD (no Cgo required)
 - Android
 - iOS
-- WebAssembly
+- WebAssembly (no Cgo required)
 - Nintendo Switch
 - Xbox
 
@@ -37,7 +36,7 @@ On some platforms you will need a C/C++ compiler in your path that Go can use.
 
 - iOS: On newer macOS versions type `clang` on your terminal and a dialog with installation instructions will appear if you don't have it
   - If you get an error with clang use xcode instead `xcode-select --install`
-- Linux and other Unix systems: Should be installed by default, but if not try [GCC](https://gcc.gnu.org/) or [Clang](https://releases.llvm.org/download.html)
+- Console targets may still need a working C/C++ toolchain; if not installed, try [GCC](https://gcc.gnu.org/) or [Clang](https://releases.llvm.org/download.html)
 
 ### macOS
 
@@ -52,25 +51,12 @@ Oto requires these frameworks:
 
 Add them to "Linked Frameworks and Libraries" on your Xcode project.
 
-### Linux
+### Linux, FreeBSD, OpenBSD
 
-ALSA is required. On Ubuntu or Debian, run this command:
+Oto uses PulseAudio on Linux and BSD systems via the pure-Go package `github.com/jfreymuth/pulse`,
+though BSD systems are not tested well.
 
-```sh
-apt install libasound2-dev
-```
-
-On RedHat-based linux distributions, run:
-
-```sh
-dnf install alsa-lib-devel
-```
-
-In most cases this command must be run by root user or through `sudo` command.
-
-### FreeBSD, OpenBSD
-
-BSD systems are not tested well. If ALSA works, Oto should work.
+If the PulseAudio server is not discoverable automatically, set `PULSE_SERVER`.
 
 ## Usage
 
@@ -222,7 +208,8 @@ This works because players implement a `Player` interface and a `BufferSizeSette
 
 ## Crosscompiling
 
-Crosscompiling to macOS or Windows is as easy as setting `GOOS=darwin` or `GOOS=windows`, respectively.
+Crosscompiling to macOS, Windows, Linux or BSD is as easy as setting `GOOS=darwin`, `GOOS=windows`,
+`GOOS=linux` or `GOOS=freebsd` (or your particular BSD flavor) respectively.
 
 To crosscompile for other platforms, make sure the libraries for the target architecture are installed, and set 
 `CGO_ENABLED=1` as Go disables [Cgo](https://golang.org/cmd/cgo/#hdr-Using_cgo_with_the_go_command) on crosscompiles by default.

context.go

@@ -73,6 +73,10 @@ type NewContextOptions struct {
 	// Too big buffer size can increase the latency time.
 	// On the other hand, too small buffer size can cause glitch noises due to buffer shortage.
 	BufferSize time.Duration
+
+	// ApplicationName specifies the name of the client application.
+	// It is used for PulseAudio's volume control UI and so on.
+	ApplicationName string
 }
 
 // NewContext creates a new context with given options.
@@ -97,7 +101,7 @@ func NewContext(options *NewContextOptions) (*Context, chan struct{}, error) {
 		bufferSizeInBytes = int(int64(options.BufferSize) * int64(bytesPerSecond) / int64(time.Second))
 		bufferSizeInBytes = bufferSizeInBytes / bytesPerSample * bytesPerSample
 	}
-	ctx, ready, err := newContext(options.SampleRate, options.ChannelCount, mux.Format(options.Format), bufferSizeInBytes)
+	ctx, ready, err := newContext(options.SampleRate, options.ChannelCount, mux.Format(options.Format), bufferSizeInBytes, options.ApplicationName)
 	if err != nil {
 		return nil, nil, err
 	}

driver_android.go

@@ -23,7 +23,7 @@ type context struct {
 	mux *mux.Mux
 }
 
-func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int) (*context, chan struct{}, error) {
+func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int, _ string) (*context, chan struct{}, error) {
 	ready := make(chan struct{})
 	close(ready)
 

driver_console.go

@@ -46,7 +46,7 @@ type context struct {
 
 var theContext *context
 
-func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int) (*context, chan struct{}, error) {
+func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int, _ string) (*context, chan struct{}, error) {
 	ready := make(chan struct{})
 	close(ready)
 

driver_darwin.go

@@ -89,7 +89,7 @@ type context struct {
 
 var theContext *context
 
-func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int) (*context, chan struct{}, error) {
+func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int, _ string) (*context, chan struct{}, error) {
 	// defaultOneBufferSizeInBytes is the default buffer size in bytes.
 	//
 	// 12288 seems necessary at least on iPod touch (7th) and MacBook Pro 2020.

driver_js.go

@@ -33,7 +33,7 @@ type context struct {
 	mux *mux.Mux
 }
 
-func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int) (*context, chan struct{}, error) {
+func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int, _ string) (*context, chan struct{}, error) {
 	ready := make(chan struct{})
 
 	class := js.Global().Get("AudioContext")