mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 13:22:19 +02:00
108 lines
3.3 KiB
Go
108 lines
3.3 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 driver
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import (
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"errors"
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"github.com/gopherjs/gopherjs/js"
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)
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type Player struct {
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sampleRate int
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channelNum int
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bytesPerSample int
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positionInSamples int64
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bufferedData []byte
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context *js.Object
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bufferSource *js.Object
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}
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func NewPlayer(sampleRate, channelNum, bytesPerSample int) (*Player, error) {
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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 nil, errors.New("driver: audio couldn't be initialized")
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}
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p := &Player{
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sampleRate: sampleRate,
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channelNum: channelNum,
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bytesPerSample: bytesPerSample,
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bufferedData: []byte{},
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bufferSource: nil,
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context: class.New(),
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}
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p.positionInSamples = int64(p.context.Get("currentTime").Float() * float64(p.sampleRate))
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return p, nil
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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 (p *Player) Proceed(data []byte) error {
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p.bufferedData = append(p.bufferedData, data...)
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c := int64(p.context.Get("currentTime").Float() * float64(p.sampleRate))
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if p.positionInSamples < c {
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p.positionInSamples = c
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}
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// Looks like low sample rate (e.g. 22050) requires a quite long buffer (#205).
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// 4096 is not perfect but it reduce noise to some extent.
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const dataSize = 4096
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for dataSize <= len(p.bufferedData) {
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data := p.bufferedData[:dataSize]
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size := len(data) / p.bytesPerSample / p.channelNum
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// TODO: size must be const or you'll get noise (e.g. sample rate is 22050)
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buf := p.context.Call("createBuffer", p.channelNum, size, p.sampleRate)
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l := buf.Call("getChannelData", 0)
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r := buf.Call("getChannelData", 1)
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il, ir := toLR(data)
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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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p.bufferSource = p.context.Call("createBufferSource")
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p.bufferSource.Set("buffer", buf)
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p.bufferSource.Call("connect", p.context.Get("destination"))
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p.bufferSource.Call("start", float64(p.positionInSamples)/float64(p.sampleRate))
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// Call 'stop' or we'll get noisy sound especially on Chrome.
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//p.bufferSource.Call("stop", float64(p.positionInSamples+int64(len(il)))/float64(p.sampleRate))
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p.positionInSamples += int64(len(il))
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p.bufferedData = p.bufferedData[dataSize:]
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}
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return nil
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}
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func (p *Player) Close() error {
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if p.bufferSource == nil {
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return nil
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}
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p.bufferSource.Call("stop")
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p.bufferSource.Call("disconnect")
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p.bufferSource = nil
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return nil
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}
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