Musical scale: Difference between revisions
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72 bpm legato c3 eb3 g3 c4 ok
</pre>
=={{header|Go}}==
{{trans|Sparkling}}
<br>
As Go doesn't have any audio support in its standard library, we instead build a .wav file which can then be played using a utility such as SoX.
<lang go>package main
import (
"encoding/binary"
"log"
"math"
"os"
"strings"
)
func main() {
const (
sampleRate = 44100
duration = 8
dataLength = sampleRate * duration
hdrSize = 44
fileLen = dataLength + hdrSize - 8
)
// buffers
buf1 := make([]byte, 1)
buf2 := make([]byte, 2)
buf4 := make([]byte, 4)
// WAV header
var sb strings.Builder
sb.WriteString("RIFF")
binary.LittleEndian.PutUint32(buf4, fileLen)
sb.Write(buf4) // file size - 8
sb.WriteString("WAVE")
sb.WriteString("fmt ")
binary.LittleEndian.PutUint32(buf4, 16)
sb.Write(buf4) // length of format data (= 16)
binary.LittleEndian.PutUint16(buf2, 1)
sb.Write(buf2) // type of format (= 1 (PCM))
sb.Write(buf2) // number of channels (= 1)
binary.LittleEndian.PutUint32(buf4, sampleRate)
sb.Write(buf4) // sample rate
sb.Write(buf4) // sample rate * bps(8) * channels(1) / 8 (= sample rate)
sb.Write(buf2) // bps(8) * channels(1) / 8 (= 1)
binary.LittleEndian.PutUint16(buf2, 8)
sb.Write(buf2) // bits per sample (bps) (= 8)
sb.WriteString("data")
binary.LittleEndian.PutUint32(buf4, dataLength)
sb.Write(buf4) // size of data section
wavhdr := []byte(sb.String())
// write WAV header
f, err := os.Create("notes.wav")
if err != nil {
log.Fatal(err)
}
defer f.Close()
f.Write(wavhdr)
// compute and write actual data
freqs := [8]float64{261.6, 293.6, 329.6, 349.2, 392.0, 440.0, 493.9, 523.3}
for j := 0; j < duration; j++ {
freq := freqs[j]
omega := 2 * math.Pi * freq
for i := 0; i < dataLength/duration; i++ {
y := 32 * math.Sin(omega*float64(i)/float64(sampleRate))
buf1[0] = byte(math.Round(y))
f.Write(buf1)
}
}
}</lang>
=={{header|J}}==
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