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Sound improvements

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This commit is contained in:
Iván Izaguirre 2022-04-18 13:23:04 +02:00
parent 15c38b091d
commit 80977143de
2 changed files with 15 additions and 14 deletions
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27
frontend/a2sdl/sdlSpeaker.go
View File

@ -51,13 +51,14 @@ func (s *sdlSpeaker) Click(cycle uint64) {
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) C.Uint8 {
if state {
return 255
return 200
}
return 0
}
@ -91,13 +92,14 @@ func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
if pc-s.lastCycle > maxOutOfSyncCycles {
// Fast forward
s.lastCycle = pc
fmt.Printf("Speaker fast forward.\n")
}
}
// Build wave
var i, p int
var i, r int
level := s.lastLevel
for p = 0; p < len(s.pendingClicks); p++ {
for p := 0; p < len(s.pendingClicks); p++ {
cycle := s.pendingClicks[p]
if cycle < s.lastCycle {
// Too old, ignore
@ -105,20 +107,23 @@ func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
}
// Fill with samples
level = stateToLevel(s.lastState)
samplesNeeded := int(float64(cycle-s.lastCycle) / sampleDurationCycles)
if samplesNeeded+i > bufferSize {
// Partial fill, to be completed on the next callback
samplesNeeded = bufferSize - 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++ {
buf[i] = level
i++
}
// Update state
s.lastCycle = cycle
s.lastState = !s.lastState
level = stateToLevel(s.lastState)
if i == bufferSize {
// Buffer is complete
break
@ -147,11 +152,7 @@ func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
s.lastLevel = level
// Remove processed clicks, store the rest for later
remainingClicks := len(s.pendingClicks) - p
for r := 0; r < remainingClicks; r++ {
s.pendingClicks[r] = s.pendingClicks[p+r]
}
s.pendingClicks = s.pendingClicks[0:remainingClicks]
s.pendingClicks = s.pendingClicks[r:]
}
func (s *sdlSpeaker) start() {

2
softSwitches2.go
View File

@ -32,7 +32,7 @@ func addApple2SoftSwitches(io *ioC0Page) {
io.addSoftSwitchRW(0x00, keySoftSwitch, "KEYBOARD") // Keyboard
io.addSoftSwitchRW(0x10, strobeKeyboardSoftSwitch, "AKD") // Keyboard Strobe
io.addSoftSwitchR(0x20, notImplementedSoftSwitchR, "TAPEOUT") // Cassette Output
io.addSoftSwitchR(0x30, speakerSoftSwitch, "SPEAKER") // Speaker
io.addSoftSwitchRW(0x30, speakerSoftSwitch, "SPEAKER") // Speaker
io.addSoftSwitchR(0x40, notImplementedSoftSwitchR, "STROBE") // Game connector Strobe
// Note: Some sources indicate that all these cover 16 positions
// for read and write. But the Apple2e takes over some of them, with