ebiten/internal/audio/audio_js.go

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2015-01-10 17:23:43 +01:00
// 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
import (
"github.com/gopherjs/gopherjs/js"
)
// Keep this so as not to be destroyed by GC.
var node js.Object
var context js.Object
const bufferSize = 1024
var (
bufferL = make([]float32, 0)
bufferR = make([]float32, 0)
)
func min(a, b int) int {
if a < b {
return a
}
return b
}
func Init() {
context = js.Global.Get("AudioContext").New()
// TODO: ScriptProcessorNode will be replaced Audio WebWorker.
// https://developer.mozilla.org/ja/docs/Web/API/ScriptProcessorNode
const bufLen = 1024
node = context.Call("createScriptProcessor", bufLen, 0, 2)
node.Call("addEventListener", "audioprocess", func(e js.Object) {
l := e.Get("outputBuffer").Call("getChannelData", 0)
r := e.Get("outputBuffer").Call("getChannelData", 1)
for i := 0; i < bufLen; i++ {
// TODO: Use copyFromChannel?
if len(bufferL) <= i {
l.SetIndex(i, 0)
r.SetIndex(i, 0)
continue
}
l.SetIndex(i, bufferL[i])
r.SetIndex(i, bufferR[i])
}
// TODO: Will the array heads be released properly on GopherJS?
usedLen := min(bufLen, len(bufferL))
bufferL = bufferL[usedLen:]
bufferR = bufferR[usedLen:]
})
}
func Start() {
// TODO: For iOS, node should be connected with a buffer node.
node.Call("connect", context.Get("destination"))
}
func Append(l []float32, r []float32) {
if len(l) != len(r) {
panic("len(l) must equal to len(r)")
}
bufferL = append(bufferL, l...)
bufferR = append(bufferR, r...)
}
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func Add(l []float32, r []float32) {
// TODO: Adjust timing for frame?
if len(l) != len(r) {
panic("len(l) must equal to len(r)")
}
m := min(len(l), len(bufferL))
for i := 0; i < m; i++ {
bufferL[i] += l[i]
bufferR[i] += r[i]
}
if m < len(l) {
bufferL = append(bufferL, l[m:]...)
bufferR = append(bufferR, r[m:]...)
}
}