ebiten/internal/audio/audio.go

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// 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.
package audio
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var audioEnabled = false
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const SampleRate = 44100
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type channel struct {
buffer []byte
nextInsertionPosition int
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}
const MaxChannel = 32
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var channels = make([]*channel, MaxChannel)
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func init() {
for i, _ := range channels {
channels[i] = &channel{
buffer: []byte{},
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}
}
}
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func Init() {
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initialize()
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}
func isPlaying(channel int) bool {
ch := channels[channel]
return ch.nextInsertionPosition < len(ch.buffer)
}
func channelAt(i int) *channel {
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if i == -1 {
for i, _ := range channels {
if !isPlaying(i) {
return channels[i]
}
}
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return nil
}
if !isPlaying(i) {
return channels[i]
}
return nil
}
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func Queue(channel int, data []byte) bool {
result := true
withChannels(func() {
if !audioEnabled {
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result = false
return
}
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ch := channelAt(channel)
if ch == nil {
result = false
return
}
ch.buffer = append(ch.buffer, data...)
})
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return result
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}
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func Tick() {
for _, ch := range channels {
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ch.nextInsertionPosition += SampleRate * 4 / 60
}
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}
func min(a, b int) int {
if a < b {
return a
}
return b
}
func isChannelsEmpty() bool {
result := false
withChannels(func() {
if !audioEnabled {
result = true
return
}
for _, ch := range channels {
if 0 < len(ch.buffer) {
return
}
}
result = true
return
})
return result
}
func loadChannelBuffer(channel int, bufferSize int) []byte {
var r []byte
withChannels(func() {
if !audioEnabled {
return
}
ch := channels[channel]
length := min(len(ch.buffer), bufferSize)
input := ch.buffer[:length]
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ch.buffer = ch.buffer[length:]
ch.nextInsertionPosition -= bufferSize
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if ch.nextInsertionPosition < 0 {
ch.nextInsertionPosition = 0
}
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r = input
})
return r
}
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func IsPlaying(channel int) bool {
result := false
withChannels(func() {
if !audioEnabled {
return
}
result = isPlaying(channel)
})
return result
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}