func (a *Audio) AppendSample(s int16) {
a.samples[a.sampleIndex] = s
a.sampleIndex++
if a.sampleIndex == SampleSize {
sdl_audio.SendAudio_int16(a.samples)
a.sampleIndex = 0
}
}
func (audio *SDLAudio) Run() {
i := 0
for {
select {
case s := <-audio.input:
audio.samples[i] = s
if i++; i == len(audio.samples) {
sdl_audio.SendAudio_int16(audio.samples)
i = 0
}
}
}
}
func (audio *SDLAudio) render(audioData *spectrum.AudioData) {
var events []spectrum.BeeperEvent
if len(audioData.BeeperEvents) > 0 {
var firstEvent *spectrum.BeeperEvent = &audioData.BeeperEvents[0]
spectrum.Assert(firstEvent.TState == 0)
var lastEvent *spectrum.BeeperEvent = &audioData.BeeperEvents[len(audioData.BeeperEvents)-1]
spectrum.Assert(lastEvent.TState == spectrum.TStatesPerFrame)
events = audioData.BeeperEvents
} else {
events = make([]spectrum.BeeperEvent, 2)
events[0] = spectrum.BeeperEvent{TState: 0, Level: 0}
events[1] = spectrum.BeeperEvent{TState: spectrum.TStatesPerFrame, Level: 0}
}
/*
// A test signal
const D = spectrum.TStatesPerFrame/128
events = make([]spectrum.BeeperEvent, spectrum.TStatesPerFrame/D+1)
for i:=uint(0); i<128; i++ {
events[i] = spectrum.BeeperEvent{TState: i*D, Level: uint8(i%2)}
}
events[len(events)-1] = spectrum.BeeperEvent{TState: spectrum.TStatesPerFrame, Level: 0}
*/
numEvents := len(events)
spread := float64(audio.freq) / RESPONSE_FREQUENCY
spread1 := 1 / spread
var numSamples int
var samples []float64
var samples_int16 []int16
var overflow []float64
{
audio.mutex.Lock()
numSamples_float := float32(audio.virtualFreq) / audioData.FPS
numSamples = int(numSamples_float)
len_overflow := int(math.Ceil(spread)) + 2
audio.numSamples_cummulativeFraction += numSamples_float - float32(numSamples)
if audio.numSamples_cummulativeFraction >= 1.0 {
numSamples += 1
audio.numSamples_cummulativeFraction -= 1.0
}
if len(audio.samples) < numSamples+len_overflow {
audio.samples = make([]float64, numSamples+len_overflow)
}
samples = audio.samples
if len(audio.samples_int16) < numSamples {
audio.samples_int16 = make([]int16, numSamples)
}
samples_int16 = audio.samples_int16
if len(audio.overflow) < len_overflow {
new_overflow := make([]float64, len_overflow)
copy(new_overflow, overflow)
audio.overflow = new_overflow
}
overflow = audio.overflow
audio.mutex.Unlock()
}
var k float64 = float64(numSamples) / spectrum.TStatesPerFrame
{
for i := 0; i < len(samples); i++ {
samples[i] = 0
}
copy(samples[:], overflow[:])
for i := 0; i < numEvents-1; i++ {
start := events[i]
end := events[i+1]
level := float64(spectrum.Audio16_Table[start.Level])
var position0 float64 = float64(start.TState) * k
var position1 float64 = float64(end.TState) * k
if audio.hqAudio {
add_hq(samples, position0+1, position1-position0, level, spread, spread1)
} else {
add_lq(samples, position0+1, position1-position0, level)
}
}
copy(overflow[:], samples[numSamples:])
}
for i := 0; i < numSamples; i++ {
const VOLUME_ADJUSTMENT = 0.5
samples_int16[i] = int16(VOLUME_ADJUSTMENT * samples[i])
}
audio.frame++
sdl_audio.SendAudio_int16(samples_int16[0:numSamples])
}