examples/pcm/main.go
func square(out []int16, volume float64, freq float64, sequence float64) {
	if freq == 0 {
		for i := 0; i < len(out); i++ {
			out[i] = 0
		}
		return
	}
	length := int(float64(sampleRate) / freq)
	if length == 0 {
		panic("invalid freq")
	}
	for i := 0; i < len(out); i++ {
		a := int16(volume * math.MaxInt16)
		if i%length < int(float64(length)*sequence) {
			a = -a
		}
		out[i] = a
	}
}
func square(out []int16, volume float64, freq float64, sequence float64) {
	if freq == 0 {
		for i := 0; i < len(out); i++ {
			out[i] = 0
		}
		return
	}
	length := int(float64(sampleRate) / freq)
	if length == 0 {
		panic("invalid freq")
	}
	for i := 0; i < len(out); i++ {
		a := int16(volume * math.MaxInt16)
		if i%length < int(float64(length)*sequence) {
			a = -a
		}
		out[i] = a
	}
}
// square fills out with square wave values with the specified volume, frequency and sequence.