audio: Refactoring

exp/audio/audio.go

@@ -22,10 +22,13 @@ func SampleRate() int {
 	return audio.SampleRate
 }
 
+// TODO: better name
 func AppendToBuffer(channel int, l []float32, r []float32) bool {
 	return audio.Append(channel, l, r)
 }
 
+// TODO: Add funciton to append samples to the buffer without adjusting.
+
 // TODO: better name
 func CurrentTime() int {
 	return audio.CurrentBytes()

internal/audio/audio.go

@@ -12,30 +12,101 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !js
-
 package audio
 
+const bufferSize = 1024
 const SampleRate = 44100
 
+var nextInsertion = 0
+var currentBytes = 0
+
+type channel struct {
+	l []float32
+	r []float32
+}
+
+var channels = make([]*channel, 16)
+
+func init() {
+	for i, _ := range channels {
+		channels[i] = &channel{
+			l: []float32{},
+			r: []float32{},
+		}
+	}
+}
+
 func Init() {
-	// TODO: Implement
+	initialize()
 }
 
 func Start() {
-	// TODO: Implement
+	start()
 }
 
 func Append(channel int, l []float32, r []float32) bool {
-	// TODO: Implement
-	return false
+	// TODO: Mutex (especially for OpenAL)
+	if len(l) != len(r) {
+		panic("len(l) must equal to len(r)")
+	}
+	ch := channelAt(channel)
+	if ch == nil {
+		return false
+	}
+	ch.l = append(ch.l, make([]float32, nextInsertion-len(ch.l))...)
+	ch.r = append(ch.r, make([]float32, nextInsertion-len(ch.r))...)
+	ch.l = append(ch.l, l...)
+	ch.r = append(ch.r, r...)
+	return true
 }
 
 func CurrentBytes() int {
-	// TODO: Implement
-	return 0
+	return currentBytes + nextInsertion
 }
 
 func Update() {
-	// TODO: Implement
+	nextInsertion += SampleRate / 60
+}
+
+func channelAt(i int) *channel {
+	if i == -1 {
+		for _, ch := range channels {
+			if len(ch.l) <= nextInsertion {
+				return ch
+			}
+		}
+		return nil
+	}
+	ch := channels[i]
+	if len(ch.l) <= nextInsertion {
+		return ch
+	}
+	return nil
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func loadChannelBuffers() (l, r []float32) {
+	inputL := make([]float32, bufferSize)
+	inputR := make([]float32, bufferSize)
+	for _, ch := range channels {
+		if len(ch.l) == 0 {
+			continue
+		}
+		l := min(len(ch.l), bufferSize)
+		for i := 0; i < l; i++ {
+			inputL[i] += ch.l[i]
+			inputR[i] += ch.r[i]
+		}
+		// TODO: Use copyFromChannel?
+		usedLen := min(bufferSize, len(ch.l))
+		ch.l = ch.l[usedLen:]
+		ch.r = ch.r[usedLen:]
+	}
+	return inputL, inputR
 }

internal/audio/audio_js.go

@@ -24,41 +24,7 @@ import (
 var node js.Object
 var context js.Object
 
-const bufferSize = 1024
-const SampleRate = 44100
-
-var nextInsertion = 0
-
-type channel struct {
-	l []float32
-	r []float32
-}
-
-var channels = make([]*channel, 16)
-
-func init() {
-	for i, _ := range channels {
-		channels[i] = &channel{
-			l: []float32{},
-			r: []float32{},
-		}
-	}
-}
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
-var currentBytes = 0
-
-func CurrentBytes() int {
-	return currentBytes + nextInsertion
-}
-
-func Init() {
+func initialize() {
 	context = js.Global.Get("AudioContext").New()
 	// TODO: ScriptProcessorNode will be replaced with Audio WebWorker.
 	// https://developer.mozilla.org/ja/docs/Web/API/ScriptProcessorNode
@@ -70,22 +36,7 @@ func Init() {
 
 		l := e.Get("outputBuffer").Call("getChannelData", 0)
 		r := e.Get("outputBuffer").Call("getChannelData", 1)
-		inputL := make([]float32, bufferSize)
-		inputR := make([]float32, bufferSize)
-		for _, ch := range channels {
-			if len(ch.l) == 0 {
-				continue
-			}
-			l := min(len(ch.l), bufferSize)
-			for i := 0; i < l; i++ {
-				inputL[i] += ch.l[i]
-				inputR[i] += ch.r[i]
-			}
-			// TODO: Use copyFromChannel?
-			usedLen := min(bufferSize, len(ch.l))
-			ch.l = ch.l[usedLen:]
-			ch.r = ch.r[usedLen:]
-		}
+		inputL, inputR := loadChannelBuffers()
 		nextInsertion -= min(bufferSize, nextInsertion)
 		for i := 0; i < bufferSize; i++ {
 			// TODO: Use copyFromChannel?
@@ -100,43 +51,7 @@ func Init() {
 	})
 }
 
-func Update() {
-	nextInsertion += SampleRate / 60
-}
-
-func Start() {
+func start() {
 	// TODO: For iOS, node should be connected with a buffer node.
 	node.Call("connect", context.Get("destination"))
 }
-
-func channelAt(i int) *channel {
-	if i == -1 {
-		for _, ch := range channels {
-			if len(ch.l) <= nextInsertion {
-				return ch
-			}
-		}
-		return nil
-	}
-	ch := channels[i]
-	if len(ch.l) <= nextInsertion {
-		return ch
-	}
-	return nil
-}
-
-func Append(i int, l []float32, r []float32) bool {
-	// TODO: Mutex (especially for OpenAL)
-	if len(l) != len(r) {
-		panic("len(l) must equal to len(r)")
-	}
-	ch := channelAt(i)
-	if ch == nil {
-		return false
-	}
-	ch.l = append(ch.l, make([]float32, nextInsertion-len(ch.l))...)
-	ch.r = append(ch.r, make([]float32, nextInsertion-len(ch.r))...)
-	ch.l = append(ch.l, l...)
-	ch.r = append(ch.r, r...)
-	return true
-}

internal/audio/audio_openal.go

@@ -0,0 +1,25 @@
+// Copyright 2015 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !js
+
+package audio
+
+func initialize() {
+	// TODO: Implement
+}
+
+func start() {
+	// TODO: Implement
+}