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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,170 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "math" | ||
| "time" | ||
|
|
||
| "github.com/ivanizag/izapple2" | ||
|
|
||
| "github.com/hajimehoshi/ebiten/v2/audio" | ||
| ) | ||
|
|
||
| const ( | ||
| samplingHz = 48000 | ||
| //bufferSize = 1000 | ||
| // bufferSize/samplingHz will be the max delay of the sound | ||
| sampleDurationCycles = 1000000 * izapple2.CPUClockMhz / samplingHz | ||
| // each sample on the sound stream is 21.31 cpu cycles approx | ||
| maxOutOfSyncMs = 2000 | ||
| decayLevel = 0.0 | ||
| ) | ||
|
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| type ebitenSpeaker struct { | ||
| audioContext *audio.Context | ||
| audioPlayer *audio.Player | ||
|
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| clickChannel chan uint64 | ||
| pendingClicks []uint64 | ||
| lastCycle uint64 | ||
| lastState bool | ||
| lastLevel float32 | ||
| } | ||
|
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| func newEbitenSpeaker() *ebitenSpeaker { | ||
| var s ebitenSpeaker | ||
| s.clickChannel = make(chan uint64, 1000) | ||
| s.pendingClicks = make([]uint64, 0, 1000) | ||
| s.lastLevel = decayLevel // Mid position to avoid starting clicks. | ||
| return &s | ||
| } | ||
|
|
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| // Click receives a speaker click. The argument is the CPU cycle when it is generated | ||
| func (s *ebitenSpeaker) Click(cycle uint64) { | ||
| select { | ||
| case s.clickChannel <- cycle: | ||
| // Sent | ||
| default: | ||
| fmt.Printf("Speaker click dropped in channel.\n") | ||
| // The channel is full, the click is lost. | ||
| } | ||
| } | ||
|
|
||
| func stateToLevel(state bool) float32 { | ||
| if state { | ||
| return 1.0 | ||
| } | ||
| return -1.0 | ||
| } | ||
|
|
||
| // Read is io.Reader's Read | ||
| func (s *ebitenSpeaker) Read(buf []byte) (n int, err error) { | ||
| //Read queued clicks | ||
| done := false | ||
| for !done { | ||
| select { | ||
| case cycle := <-s.clickChannel: | ||
| s.pendingClicks = append(s.pendingClicks, cycle) | ||
| default: | ||
| done = true | ||
| } | ||
| } | ||
|
|
||
| // Verify that we are not too long behind | ||
| var maxOutOfSyncCyclesFloat = 1000 * izapple2.CPUClockMhz * maxOutOfSyncMs | ||
| var maxOutOfSyncCycles = uint64(maxOutOfSyncCyclesFloat) | ||
| for _, pc := range s.pendingClicks { | ||
| if pc-s.lastCycle > maxOutOfSyncCycles { | ||
| // Fast forward | ||
| s.lastCycle = pc | ||
| fmt.Printf("Speaker fast forward.\n") | ||
| } | ||
| } | ||
|
|
||
| // Build wave | ||
| const bytesPerSample = 8 // Two floats32, 4 bytes each, one for each channel | ||
| samples := len(buf) / bytesPerSample | ||
| //fmt.Printf("smples: %v\n", smples) | ||
|
|
||
| if len(s.pendingClicks) > 0 { | ||
| fmt.Printf("pendingClicks: %v\n", len(s.pendingClicks)) | ||
| } | ||
| var i, r int | ||
| level := s.lastLevel | ||
| for p := 0; p < len(s.pendingClicks); p++ { | ||
| cycle := s.pendingClicks[p] | ||
| if cycle < s.lastCycle { | ||
| // Too old, ignore | ||
| continue | ||
| } | ||
|
|
||
| // Fill with samples | ||
| level = stateToLevel(s.lastState) | ||
| samplesNeeded := int(float64(cycle-s.lastCycle) / sampleDurationCycles) | ||
| if samplesNeeded+i > samples { | ||
| // Partial fill, to be completed on the next callback | ||
| samplesNeeded = samples - i | ||
| s.lastCycle = cycle - uint64(float64(samplesNeeded)*sampleDurationCycles) | ||
| } else { | ||
| s.lastCycle = cycle | ||
| s.lastState = !s.lastState | ||
| r++ // Remove this pending click | ||
| } | ||
|
|
||
| for j := 0; j < samplesNeeded; j++ { | ||
| putFloat32InBuffer(buf, i, level) | ||
| i += 1 | ||
| } | ||
|
|
||
| if i == samples { | ||
| // Buffer is complete | ||
| break | ||
| } | ||
| } | ||
|
|
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| // If the buffer is empty lets stop the signal | ||
| if i == 0 && level != 0.0 { | ||
| level = 0.0 | ||
| fmt.Printf("Speaker buffer empty, to zero.\n") | ||
| } | ||
|
|
||
| // Complete the buffer if needed | ||
| for b := i; b < samples; b++ { | ||
| putFloat32InBuffer(buf, b, level) | ||
| } | ||
| s.lastLevel = level | ||
|
|
||
| // Remove processed clicks, store the rest for later | ||
| s.pendingClicks = s.pendingClicks[r:] | ||
|
|
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| return len(buf), nil | ||
| } | ||
|
|
||
| func putFloat32InBuffer(buf []byte, i int, f float32) { | ||
| v := math.Float32bits(f) | ||
| buf[i*8] = byte(v) | ||
| buf[i*8+1] = byte(v >> 8) | ||
| buf[i*8+2] = byte(v >> 16) | ||
| buf[i*8+3] = byte(v >> 24) | ||
| buf[i*8+4] = byte(v) | ||
| buf[i*8+5] = byte(v >> 8) | ||
| buf[i*8+6] = byte(v >> 16) | ||
| buf[i*8+7] = byte(v >> 24) | ||
| } | ||
|
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| func (s *ebitenSpeaker) update() error { | ||
| if s.audioContext == nil { | ||
| s.audioContext = audio.NewContext(samplingHz) | ||
| } | ||
| if s.audioPlayer == nil { | ||
| var err error | ||
| s.audioPlayer, err = s.audioContext.NewPlayerF32(s) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| //s.audioPlayer.SetVolume(1.0) | ||
| s.audioPlayer.SetBufferSize(time.Duration(100) * time.Millisecond) | ||
| s.audioPlayer.Play() | ||
| } | ||
| return nil | ||
| } |
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