mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
103 lines
2.6 KiB
Go
103 lines
2.6 KiB
Go
// Copyright 2015 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build js
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package audio
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import (
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"github.com/gopherjs/gopherjs/js"
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)
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func withChannels(f func()) {
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f()
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}
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// Keep this so as not to be destroyed by GC.
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var (
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nodes = []*js.Object{}
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dummies = []*js.Object{} // Dummy source nodes for iOS.
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context *js.Object
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)
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const bufferSize = 1024
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type audioProcessor struct {
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channel int
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}
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func toLR(data []byte) ([]int16, []int16) {
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l := make([]int16, len(data)/4)
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r := make([]int16, len(data)/4)
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for i := 0; i < len(data)/4; i++ {
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l[i] = int16(data[4*i]) | int16(data[4*i+1])<<8
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r[i] = int16(data[4*i+2]) | int16(data[4*i+3])<<8
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}
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return l, r
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}
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func (a *audioProcessor) Process(e *js.Object) {
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// Can't use 'go' here. Probably it may cause race conditions.
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b := e.Get("outputBuffer")
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l := b.Call("getChannelData", 0)
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r := b.Call("getChannelData", 1)
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inputL, inputR := toLR(loadChannelBuffer(a.channel, bufferSize*4))
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const max = 1 << 15
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for i := 0; i < len(inputL); i++ {
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// TODO: Use copyToChannel?
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l.SetIndex(i, float64(inputL[i])/max)
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r.SetIndex(i, float64(inputR[i])/max)
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}
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}
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func initialize() {
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// Do nothing in node.js.
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if js.Global.Get("require") != js.Undefined {
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return
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}
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class := js.Global.Get("AudioContext")
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if class == js.Undefined {
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class = js.Global.Get("webkitAudioContext")
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}
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if class == js.Undefined {
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return
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}
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context = class.New()
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// TODO: ScriptProcessorNode will be replaced with Audio WebWorker.
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// https://developer.mozilla.org/ja/docs/Web/API/ScriptProcessorNode
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for i := 0; i < MaxChannel; i++ {
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node := context.Call("createScriptProcessor", bufferSize, 0, 2)
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processor := &audioProcessor{i}
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node.Call("addEventListener", "audioprocess", processor.Process)
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nodes = append(nodes, node)
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dummy := context.Call("createBufferSource")
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dummies = append(dummies, dummy)
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}
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audioEnabled = true
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// Do nothing in node.js.
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if js.Global.Get("require") != js.Undefined {
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return
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}
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destination := context.Get("destination")
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for i, node := range nodes {
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dummy := dummies[i]
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dummy.Call("connect", node)
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node.Call("connect", destination)
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}
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}
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