ebiten/exp/audio/internal/audio_js.go
2015-02-16 02:23:04 +09:00

94 lines
2.3 KiB
Go

// 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 internal
import (
"github.com/gopherjs/gopherjs/js"
)
func withChannels(f func()) {
f()
}
// Keep this so as not to be destroyed by GC.
var (
nodes = []js.Object{}
dummies = []js.Object{} // Dummy source nodes for iOS.
context js.Object
)
const bufferSize = 1024
func audioProcess(channel int) func(e js.Object) {
return func(e js.Object) {
// Can't use 'go' here. Probably it may cause race conditions.
defer func() {
currentPosition += bufferSize
}()
b := e.Get("outputBuffer")
l := b.Call("getChannelData", 0)
r := b.Call("getChannelData", 1)
inputL, inputR := loadChannelBuffer(channel, bufferSize)
const max = 1 << 15
for i := 0; i < bufferSize; i++ {
// TODO: Use copyToChannel?
if len(inputL) <= i {
l.SetIndex(i, 0)
r.SetIndex(i, 0)
continue
}
l.SetIndex(i, float64(inputL[i])/max)
r.SetIndex(i, float64(inputR[i])/max)
}
}
}
func initialize() {
// Do nothing in node.js.
if js.Global.Get("require") != js.Undefined {
return
}
context = js.Global.Get("AudioContext").New()
// TODO: ScriptProcessorNode will be replaced with Audio WebWorker.
// https://developer.mozilla.org/ja/docs/Web/API/ScriptProcessorNode
for i := 0; i < MaxChannel; i++ {
node := context.Call("createScriptProcessor", bufferSize, 0, 2)
node.Call("addEventListener", "audioprocess", audioProcess(i))
nodes = append(nodes, node)
dummy := context.Call("createBufferSource")
dummies = append(dummies, dummy)
}
audioEnabled = true
}
func start() {
// Do nothing in node.js.
if js.Global.Get("require") != js.Undefined {
return
}
destination := context.Get("destination")
for i, node := range nodes {
dummy := dummies[i]
dummy.Call("connect", node)
node.Call("connect", destination)
}
}