// drawFrequonsFourier draws the frequency-domain representation of Frequons.
func drawFrequonsFourier(pm nimble.PixMap) {
c := universe.Zoo
h := harmonicStorage[:len(c)]
var ampScale float32
if autoGain.Value {
// Compute L1 norm of amplitudes
norm := float32(0)
for i := range c {
norm += math32.Abs(c[i].Amplitude)
}
ampScale = 1 / norm
} else {
ampScale = 1 / float32(len(c))
}
fracX, fracY := universe.BoxFraction()
fracX *= zoomCompression
fracY *= zoomCompression
sizeX, sizeY := pm.Size()
// Set up harmonics
// (cx,cy) is center of fourier view
cx, cy := 0.5*float32(sizeX)*fracX, 0.5*float32(sizeY)*fracY
α, β := -0.5*cx, -0.5*cy
ωScale := 200. / float32(sizeX*sizeY)
for i := range h {
ωx := (c[i].Sx - cx) * ωScale
ωy := (c[i].Sy - cy) * ωScale
h[i].Ωx = ωx
h[i].Ωy = ωy
h[i].Phase = α*ωx + β*ωy + phaseRoll
// Scale amplitude so that DFT values fit within domain of color lookup table.
h[i].Amplitude = c[i].Amplitude * ampScale
}
marginX := int32(math32.Round(0.5 * float32(sizeX) * (1 - fracX)))
marginY := int32(math32.Round(0.5 * float32(sizeY) * (1 - fracY)))
fourier.Draw(pm.Intersect(nimble.Rect{
Left: marginX,
Right: sizeX - marginX,
Top: marginY,
Bottom: sizeY - marginY,
}), h, universe.Scheme())
if marginX != 0 || marginY != 0 {
pm.DrawRect(nimble.Rect{Left: 0, Right: sizeX, Top: 0, Bottom: marginY}, nimble.Black)
pm.DrawRect(nimble.Rect{Left: 0, Right: sizeX, Top: sizeY - marginY, Bottom: sizeY}, nimble.Black)
pm.DrawRect(nimble.Rect{Left: 0, Right: marginX, Top: marginY, Bottom: sizeY - marginY}, nimble.Black)
pm.DrawRect(nimble.Rect{Left: sizeX - marginX, Right: sizeX, Top: marginY, Bottom: sizeY - marginY}, nimble.Black)
}
}
func init() {
Twang = makeSound(44100, func(i float32) float32 {
const ω = 110 * 2 * π / nimble.SampleRate
const nharmonic = 32
sum := float32(0)
for h := float32(1); h <= nharmonic; h++ {
sum += math32.Sin(ω*h*i) * math32.Exp(-i*0.00004*h)
}
return sum / nharmonic
})
n := len(Twang)
AntiTwang = make([]float32, n)
for i := range AntiTwang {
AntiTwang[i] = Twang[n-1-i]
}
sum := float32(0)
Broken = makeSound(44100, func(i float32) float32 {
r := (rand.Float32() - 0.5) * (1.0 / 16)
newSum := sum + r
if math32.Abs(newSum) < 1.0 {
sum = newSum
}
sum *= (1 - 1/32.0)
return sum * math32.Exp(-i*.0001)
})
Wobble = makeSound(44100, func(i float32) float32 {
return 0.25 * math32.Sin((440+44*math32.Sin(i*0.001))*i*(2*π/nimble.SampleRate)) * math32.Exp(-i*0.00005)
})
partials := [...]float32{0.56, 0.92, 1.19, 1.71, 2.00, 2.74, 3.00, 3.76, 4.07}
Bell = makeSound(44100, func(i float32) float32 {
const θ = 512 * 2 * π / nimble.SampleRate
sum := float32(0)
const n = float32(len(partials))
for j := range partials {
sum += math32.Sin(i * θ * partials[j])
}
return sum * (1.0 / n) * math32.Exp(-i*0.0001)
})
}