Adding upstream version 0.0~git20250520.a1d9079+dfsg.

Signed-off-by: Daniel Baumann <daniel@debian.org>

exp/audio/al/alc.go

@@ -0,0 +1,74 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin || linux || windows
+
+package al
+
+import (
+	"errors"
+	"sync"
+	"unsafe"
+)
+
+var (
+	mu      sync.Mutex
+	device  unsafe.Pointer
+	context unsafe.Pointer
+)
+
+// DeviceError returns the last known error from the current device.
+func DeviceError() int32 {
+	return alcGetError(device)
+}
+
+// TODO(jbd): Investigate the cases where multiple audio output
+// devices might be needed.
+
+// OpenDevice opens the default audio device.
+// Calls to OpenDevice are safe for concurrent use.
+func OpenDevice() error {
+	mu.Lock()
+	defer mu.Unlock()
+
+	// already opened
+	if device != nil {
+		return nil
+	}
+
+	dev := alcOpenDevice("")
+	if dev == nil {
+		return errors.New("al: cannot open the default audio device")
+	}
+	ctx := alcCreateContext(dev, nil)
+	if ctx == nil {
+		alcCloseDevice(dev)
+		return errors.New("al: cannot create a new context")
+	}
+	if !alcMakeContextCurrent(ctx) {
+		alcCloseDevice(dev)
+		return errors.New("al: cannot make context current")
+	}
+	device = dev
+	context = ctx
+	return nil
+}
+
+// CloseDevice closes the device and frees related resources.
+// Calls to CloseDevice are safe for concurrent use.
+func CloseDevice() {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if device == nil {
+		return
+	}
+
+	alcCloseDevice(device)
+	if context != nil {
+		alcDestroyContext(context)
+	}
+	device = nil
+	context = nil
+}