MXL audio sample player app

internal/sdl/sdl.go

@@ -20,19 +20,35 @@ const (
 
 	KeyEscape uint32 = 0x1B
 	KeyF      uint32 = 0x66
+
+	InitAudio                  uint32 = 0x00000010
+	AudioDeviceDefaultPlayback uint32 = 0xFFFFFFFF
+	AudioF32                   uint16 = 0x8120
 )
 
 var (
-	sdlInit                        func(flags uint32) bool
-	sdlQuit                        func()
-	sdlGetError                    func() uintptr
-	sdlCreateWindow                func(title *byte, w, h int32, flags uint64) uintptr
-	sdlDestroyWindow               func(window uintptr)
+	sdlInit     func(flags uint32) bool
+	sdlQuit     func()
+	sdlGetError func() uintptr
+
+	sdlCreateWindow  func(title *byte, w, h int32, flags uint64) uintptr
+	sdlDestroyWindow func(window uintptr)
+
 	sdlVulkanGetInstanceExtensions func(count *uint32) uintptr
 	sdlVulkanCreateSurface         func(window, instance, allocator uintptr, surface *uint64) bool
-	sdlPollEvent                   func(event unsafe.Pointer) bool
-	sdlGetWindowSizeInPixels       func(window uintptr, w, h *int32) bool
-	sdlSetWindowFullscreen         func(window uintptr, fullscreen bool) bool
+
+	sdlPollEvent func(event unsafe.Pointer) bool
+
+	sdlGetWindowSizeInPixels func(window uintptr, w, h *int32) bool
+	sdlSetWindowFullscreen   func(window uintptr, fullscreen bool) bool
+
+	sdlOpenAudioDeviceStream   func(devid uint32, spec unsafe.Pointer, callback uintptr, userdata uintptr) uintptr
+	sdlResumeAudioStreamDevice func(stream uintptr) bool
+	sdlPutAudioStreamData      func(stream uintptr, buf unsafe.Pointer, length int32) bool
+	sdlGetAudioStreamQueued    func(stream uintptr) int32
+	sdlDestroyAudioStream      func(stream uintptr)
+	sdlGetAudioPlaybackDevices func(count *int32) uintptr
+	sdlGetAudioDeviceName      func(devid uint32) uintptr
 )
 
 var loaded = false
@@ -55,6 +71,14 @@ func Load() error {
 	purego.RegisterLibFunc(&sdlPollEvent, h, "SDL_PollEvent")
 	purego.RegisterLibFunc(&sdlGetWindowSizeInPixels, h, "SDL_GetWindowSizeInPixels")
 	purego.RegisterLibFunc(&sdlSetWindowFullscreen, h, "SDL_SetWindowFullscreen")
+	// audio
+	purego.RegisterLibFunc(&sdlOpenAudioDeviceStream, h, "SDL_OpenAudioDeviceStream")
+	purego.RegisterLibFunc(&sdlResumeAudioStreamDevice, h, "SDL_ResumeAudioStreamDevice")
+	purego.RegisterLibFunc(&sdlPutAudioStreamData, h, "SDL_PutAudioStreamData")
+	purego.RegisterLibFunc(&sdlGetAudioStreamQueued, h, "SDL_GetAudioStreamQueued")
+	purego.RegisterLibFunc(&sdlDestroyAudioStream, h, "SDL_DestroyAudioStream")
+	purego.RegisterLibFunc(&sdlGetAudioPlaybackDevices, h, "SDL_GetAudioPlaybackDevices")
+	purego.RegisterLibFunc(&sdlGetAudioDeviceName, h, "SDL_GetAudioDeviceName")
 	loaded = true
 	return nil
 }
@@ -113,3 +137,40 @@ func cbytes(s string) *byte {
 	runtime.KeepAlive(b)
 	return &b[0]
 }
+
+type AudioSpec struct {
+	Format   uint16
+	Channels int32
+	Freq     int32
+}
+
+func OpenAudioDeviceStream(devid uint32, spec AudioSpec) uintptr {
+	return sdlOpenAudioDeviceStream(devid, unsafe.Pointer(&spec), 0, 0)
+}
+func ResumeAudioStreamDevice(stream uintptr) bool { return sdlResumeAudioStreamDevice(stream) }
+func DestroyAudioStream(stream uintptr)           { sdlDestroyAudioStream(stream) }
+func PutAudioStreamData(stream uintptr, buf []byte) bool {
+	return sdlPutAudioStreamData(stream, unsafe.Pointer(&buf[0]), int32(len(buf)))
+}
+func GetAudioStreamQueued(stream uintptr) int32 { return sdlGetAudioStreamQueued(stream) }
+
+// playback device
+type AudioDevice struct {
+	ID   uint32
+	Name string
+}
+
+func GetAudioPlaybackDevices() []AudioDevice {
+	var count int32
+	ptr := sdlGetAudioPlaybackDevices(&count)
+	if ptr == 0 || count == 0 {
+		return nil
+	}
+	ids := unsafe.Slice((*uint32)(unsafe.Pointer(ptr)), count)
+	devs := make([]AudioDevice, 0, count)
+	for _, id := range ids {
+		name := cstr(sdlGetAudioDeviceName(id))
+		devs = append(devs, AudioDevice{ID: id, Name: name})
+	}
+	return devs
+}