mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
109 lines
2.7 KiB
Go
109 lines
2.7 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 as global 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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type audioProcessor struct {
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channel int
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sampleRate int
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position float64
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}
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var audioProcessors [MaxChannel]*audioProcessor
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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) playChunk(buf []byte) {
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if len(buf) == 0 {
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return
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}
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const channelNum = 2
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const bytesPerSample = channelNum * 16 / 8
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b := context.Call("createBuffer", channelNum, len(buf)/bytesPerSample, a.sampleRate)
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l := b.Call("getChannelData", 0)
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r := b.Call("getChannelData", 1)
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il, ir := toLR(buf)
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const max = 1 << 15
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for i := 0; i < len(il); i++ {
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l.SetIndex(i, float64(il[i])/max)
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r.SetIndex(i, float64(ir[i])/max)
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}
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s := context.Call("createBufferSource")
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s.Set("buffer", b)
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s.Call("connect", context.Get("destination"))
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c := context.Get("currentTime").Float()
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if a.position < c {
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a.position = c
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}
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s.Call("start", a.position)
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a.position += float64(len(il)) / float64(a.sampleRate)
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}
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func isPlaying(channel int) bool {
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c := context.Get("currentTime").Float()
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return c < audioProcessors[channel].position
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}
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func tick() {
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const bufferSize = 1024
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for _, a := range audioProcessors {
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a.playChunk(loadChannelBuffer(a.channel, bufferSize*4))
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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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audioEnabled = true
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for i := 0; i < len(audioProcessors); i++ {
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audioProcessors[i] = &audioProcessor{
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channel: i,
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sampleRate: 44100, // TODO: Change this for each chunks
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position: 0,
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}
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}
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}
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