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examples/pcm: use NewPlayerF32FromBytes

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Updates #2160
This commit is contained in:
Hajime Hoshi 2024-07-22 23:20:56 +09:00
parent fd382d26ae
commit a12e32faf9
1 changed files with 21 additions and 15 deletions
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36
examples/pcm/main.go
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@ -51,20 +51,20 @@ var score = strings.Replace(
" ", "", -1) " ", "", -1)
// square fills out with square wave values with the specified volume, frequency and sequence. // square fills out with square wave values with the specified volume, frequency and sequence.
func square(out []int16, volume float64, freq float64, sequence float64) { func square(out []float32, volume float32, freq float32, sequence float32) {
if freq == 0 { if freq == 0 {
for i := 0; i < len(out); i++ { for i := 0; i < len(out); i++ {
out[i] = 0 out[i] = 0
} }
return return
} }
length := int(float64(sampleRate) / freq) length := int(sampleRate / freq)
if length == 0 { if length == 0 {
panic("invalid freq") panic("invalid freq")
} }
for i := 0; i < len(out); i++ { for i := 0; i < len(out); i++ {
a := int16(volume * math.MaxInt16) a := volume
if i%length < int(float64(length)*sequence) { if i%length < int(float32(length)*sequence) {
a = -a a = -a
} }
out[i] = a out[i] = a
@ -72,16 +72,22 @@ func square(out []int16, volume float64, freq float64, sequence float64) {
} }
// toBytes returns the 2ch little endian 16bit byte sequence with the given left/right sequence. // toBytes returns the 2ch little endian 16bit byte sequence with the given left/right sequence.
func toBytes(l, r []int16) []byte { func toBytes(l, r []float32) []byte {
if len(l) != len(r) { if len(l) != len(r) {
panic("len(l) must equal to len(r)") panic("len(l) must equal to len(r)")
} }
b := make([]byte, len(l)*4) b := make([]byte, len(l)*8)
for i := range l { for i := range l {
b[4*i] = byte(l[i]) lv := math.Float32bits(l[i])
b[4*i+1] = byte(l[i] >> 8) rv := math.Float32bits(r[i])
b[4*i+2] = byte(r[i]) b[8*i] = byte(lv)
b[4*i+3] = byte(r[i] >> 8) b[8*i+1] = byte(lv >> 8)
b[8*i+2] = byte(lv >> 16)
b[8*i+3] = byte(lv >> 24)
b[8*i+4] = byte(rv)
b[8*i+5] = byte(rv >> 8)
b[8*i+6] = byte(rv >> 16)
b[8*i+7] = byte(rv >> 24)
} }
return b return b
} }
@ -109,8 +115,8 @@ func (g *Game) playNote(scoreIndex int) rune {
return rune(note) return rune(note)
} }
freqs := []float64{freqC, freqD, freqE, freqF, freqG, freqA * 2, freqB * 2} freqs := []float32{freqC, freqD, freqE, freqF, freqG, freqA * 2, freqB * 2}
freq := 0.0 var freq float32
switch { switch {
case 'A' <= note && note <= 'B': case 'A' <= note && note <= 'B':
freq = freqs[int(note)+len(freqs)-int('C')] freq = freqs[int(note)+len(freqs)-int('C')]
@ -122,12 +128,12 @@ func (g *Game) playNote(scoreIndex int) rune {
const vol = 1.0 / 16.0 const vol = 1.0 / 16.0
size := (ebiten.TPS()/2 - 2) * sampleRate / ebiten.TPS() size := (ebiten.TPS()/2 - 2) * sampleRate / ebiten.TPS()
l := make([]int16, size) l := make([]float32, size)
r := make([]int16, size) r := make([]float32, size)
square(l, vol, freq, 0.25) square(l, vol, freq, 0.25)
square(r, vol, freq, 0.25) square(r, vol, freq, 0.25)
p := g.audioContext.NewPlayerFromBytes(toBytes(l, r)) p := g.audioContext.NewPlayerF32FromBytes(toBytes(l, r))
p.Play() p.Play()
return rune(note) return rune(note)