Beispiel #1
0
func addNote() {
	size := audio.SampleRate() / 60
	notes := []float64{freqC, freqD, freqE, freqF, freqG, freqA * 2, freqB * 2}

	defer func() {
		scoreIndex++
		scoreIndex %= len(score)
	}()
	l := make([]int16, size*30)
	r := make([]int16, size*30)
	note := score[scoreIndex]
	for note == ' ' {
		scoreIndex++
		scoreIndex %= len(score)
		note = score[scoreIndex]
	}
	freq := 0.0
	switch {
	case note == 'R':
		freq = 0
	case note <= 'B':
		freq = notes[int(note)+len(notes)-int('C')]
	default:
		freq = notes[note-'C']
	}
	vol := 1.0 / 16.0
	square(l, vol, freq, 0.25)
	square(r, vol, freq, 0.25)
	audio.Play(0, toBytes(l, r))
}
Beispiel #2
0
func init() {
	s := float64(audio.SampleRate())
	amp := []float64{1.0, 0.8, 0.6, 0.4, 0.2}
	x := []float64{4.0, 2.0, 1.0, 0.5, 0.25}
	for i := 0; i < len(pcm); i++ {
		v := 0.0
		twoPiF := 2.0 * math.Pi * baseFreq
		for j := 0; j < len(amp); j++ {
			a := amp[j] * math.Exp(-5*float64(i)/(x[j]*s))
			v += a * math.Sin(float64(i)*twoPiF*float64(j+1)/s)
		}
		pcm[i] = v / 5.0
	}
}
Beispiel #3
0
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(audio.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
	}
}
Beispiel #4
0
	"image/color"
	"log"
	"math"

	"github.com/hajimehoshi/ebiten"
	"github.com/hajimehoshi/ebiten/ebitenutil"
	"github.com/hajimehoshi/ebiten/example/common"
	"github.com/hajimehoshi/ebiten/exp/audio"
)

const (
	screenWidth  = 320
	screenHeight = 240
)

var pcm = make([]float64, 4*audio.SampleRate())

const baseFreq = 220

func init() {
	s := float64(audio.SampleRate())
	amp := []float64{1.0, 0.8, 0.6, 0.4, 0.2}
	x := []float64{4.0, 2.0, 1.0, 0.5, 0.25}
	for i := 0; i < len(pcm); i++ {
		v := 0.0
		twoPiF := 2.0 * math.Pi * baseFreq
		for j := 0; j < len(amp); j++ {
			a := amp[j] * math.Exp(-5*float64(i)/(x[j]*s))
			v += a * math.Sin(float64(i)*twoPiF*float64(j+1)/s)
		}
		pcm[i] = v / 5.0