mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
143 lines
3.1 KiB
Go
143 lines
3.1 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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// Keep this so as not to be destroyed by GC.
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var node js.Object
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var context js.Object
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const bufferSize = 1024
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const SampleRate = 44100
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var nextInsertion = 0
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type channel struct {
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l []float32
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r []float32
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}
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var channels = make([]*channel, 16)
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func init() {
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for i, _ := range channels {
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channels[i] = &channel{
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l: []float32{},
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r: []float32{},
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}
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}
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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var currentBytes = 0
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func CurrentBytes() int {
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return currentBytes + nextInsertion
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}
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func Init() {
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context = js.Global.Get("AudioContext").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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node = context.Call("createScriptProcessor", bufferSize, 0, 2)
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node.Call("addEventListener", "audioprocess", func(e js.Object) {
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defer func() {
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currentBytes += bufferSize
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}()
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l := e.Get("outputBuffer").Call("getChannelData", 0)
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r := e.Get("outputBuffer").Call("getChannelData", 1)
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inputL := make([]float32, bufferSize)
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inputR := make([]float32, bufferSize)
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for _, ch := range channels {
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if len(ch.l) == 0 {
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continue
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}
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l := min(len(ch.l), bufferSize)
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for i := 0; i < l; i++ {
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inputL[i] += ch.l[i]
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inputR[i] += ch.r[i]
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}
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// TODO: Use copyFromChannel?
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usedLen := min(bufferSize, len(ch.l))
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ch.l = ch.l[usedLen:]
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ch.r = ch.r[usedLen:]
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}
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nextInsertion -= min(bufferSize, nextInsertion)
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for i := 0; i < bufferSize; i++ {
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// TODO: Use copyFromChannel?
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if len(inputL) <= i {
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l.SetIndex(i, 0)
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r.SetIndex(i, 0)
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continue
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}
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l.SetIndex(i, inputL[i])
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r.SetIndex(i, inputR[i])
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}
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})
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}
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func Update() {
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nextInsertion += SampleRate / 60
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}
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func Start() {
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// TODO: For iOS, node should be connected with a buffer node.
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node.Call("connect", context.Get("destination"))
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}
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func channelAt(i int) *channel {
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if i == -1 {
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for _, ch := range channels {
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if len(ch.l) <= nextInsertion {
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return ch
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}
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}
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return nil
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}
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ch := channels[i]
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if len(ch.l) <= nextInsertion {
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return ch
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}
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return nil
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}
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func Append(i int, l []float32, r []float32) bool {
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// TODO: Mutex (especially for OpenAL)
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if len(l) != len(r) {
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panic("len(l) must equal to len(r)")
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}
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ch := channelAt(i)
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if ch == nil {
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return false
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}
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ch.l = append(ch.l, make([]float32, nextInsertion-len(ch.l))...)
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ch.r = append(ch.r, make([]float32, nextInsertion-len(ch.r))...)
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ch.l = append(ch.l, l...)
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ch.r = append(ch.r, r...)
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return true
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}
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