add perlin noise

This commit is contained in:
Yongwei Xing 2021-03-09 13:41:11 +08:00
parent c25daba2ed
commit eddb3f9709
3 changed files with 115 additions and 15 deletions

100
common/perlinnoise.go Normal file
View file

@ -0,0 +1,100 @@
package common
import (
"math"
"math/rand"
)
const (
perlinYwrapb = 4
perlinYwrap = 1 << perlinYwrapb
perlinZwrapb = 8
perlinZwrap = 1 << perlinZwrapb
perlinSize = 4095
perlinOctaves = 4
perlinAmpFalloff = 0.5
)
type perlinNoise struct {
perlin []float64
}
func NewPerlinNoise() *perlinNoise {
perlin := &perlinNoise{perlin: nil}
perlin.perlin = make([]float64, perlinSize+1)
for i, _ := range perlin.perlin {
perlin.perlin[i] = rand.Float64()
}
return perlin
}
func (p *perlinNoise) Noise(x, y, z float64) float64 {
if x < 0 {
x = -x
}
if y < 0 {
y = -y
}
if z < 0 {
z = -z
}
xi, yi, zi := int(math.Floor(x)), int(math.Floor(y)), int(math.Floor(z))
xf, yf, zf := x-float64(xi), y-float64(yi), z-float64(zi)
var rxf, ryf, n1, n2, n3 float64
var r float64
var ampl float64 = 0.5
for o := 0; o < perlinOctaves; o++ {
of := xi + (yi << perlinYwrapb) + (zi << perlinZwrapb)
rxf = scaledCosin(xf)
ryf = scaledCosin(yf)
n1 = p.perlin[of&perlinSize]
n1 += rxf * (p.perlin[(of+1)&perlinSize] - n1)
n2 = p.perlin[(of+perlinYwrap)&perlinSize]
n2 += rxf * (p.perlin[(of+perlinYwrap+1)&perlinSize] - n2)
n1 += ryf * (n2 - n1)
of += perlinZwrap
n2 = p.perlin[of&perlinSize]
n2 += rxf * (p.perlin[(of+1)&perlinSize] - n2)
n3 = p.perlin[(of+perlinYwrap)&perlinSize]
n3 += rxf * (p.perlin[(of+perlinYwrap+1)&perlinSize] - n3)
n2 += ryf * (n3 - n2)
n1 += scaledCosin(zf) * (n2 - n1)
r += n1 * ampl
ampl *= perlinAmpFalloff
xi <<= 1
xf *= 2
yi <<= 1
yf *= 2
zi <<= 1
zf *= 2
if xf >= 1.0 {
xi += 1
xf -= 1
}
if yf >= 1.0 {
yi += 1
yf -= 1
}
if zf >= 1.0 {
zi += 1
zf -= 1
}
}
return r
}
func scaledCosin(x float64) float64 {
return 0.5 * (1.0 - math.Cos(x*math.Pi))
}

View file

@ -11,7 +11,7 @@ type contourLine struct {
lineNum int lineNum int
} }
func NewContourLine(lineNum int) *contourLine{ func NewContourLine(lineNum int) *contourLine {
return &contourLine{ return &contourLine{
lineNum: lineNum, lineNum: lineNum,
} }
@ -22,24 +22,24 @@ func (cl *contourLine) Generative(c *canva) {
ctex := gg.NewContextForRGBA(c.img) ctex := gg.NewContextForRGBA(c.img)
noise := perlin.NewPerlin(2, 2, 3, rand.Int63()) noise := perlin.NewPerlin(2, 2, 3, rand.Int63())
for i:=0; i<cl.lineNum;i++ { for i := 0; i < cl.lineNum; i++ {
cl := c.opts.colorSchema[rand.Intn(len(c.opts.colorSchema))] cl := c.opts.colorSchema[rand.Intn(len(c.opts.colorSchema))]
for j :=0; j<5;j++ { for j := 0; j < 5; j++ {
x := rand.Float64()*float64(c.width) x := rand.Float64() * float64(c.width)
y := rand.Float64()*float64(c.height) y := rand.Float64() * float64(c.height)
theta := noise.Noise2D(x/800.0, y/800.0) * math.Pi*2*800 theta := noise.Noise2D(x/800.0, y/800.0) * math.Pi * 2 * 800
x += math.Cos(theta)*0.4 x += math.Cos(theta) * 0.4
y += math.Sin(theta)*0.4 y += math.Sin(theta) * 0.4
ctex.SetColor(cl) ctex.SetColor(cl)
ctex.DrawEllipse(x, y, 1, 1) ctex.DrawEllipse(x, y, 1, 1)
ctex.Fill() ctex.Fill()
if x > float64(c.width) || x < 0 || y > float64(c.height) || y < 0 || rand.Float64() < 0.001 { if x > float64(c.width) || x < 0 || y > float64(c.height) || y < 0 || rand.Float64() < 0.001 {
x = rand.Float64()*float64(c.width) x = rand.Float64() * float64(c.width)
y = rand.Float64()*float64(c.height) y = rand.Float64() * float64(c.height)
} }
} }
} }

View file

@ -10,11 +10,11 @@ import (
func main() { func main() {
rand.Seed(time.Now().Unix()) rand.Seed(time.Now().Unix())
colors := []color.RGBA{ colors := []color.RGBA{
{0x58, 0x18, 0x45, 0xFF }, {0x58, 0x18, 0x45, 0xFF},
{0x90, 0x0C, 0x3F, 0xFF }, {0x90, 0x0C, 0x3F, 0xFF},
{0xC7, 0x00, 0x39, 0xFF }, {0xC7, 0x00, 0x39, 0xFF},
{0xFF, 0x57, 0x33, 0xFF }, {0xFF, 0x57, 0x33, 0xFF},
{0xFF, 0xC3, 0x0F, 0xFF }, {0xFF, 0xC3, 0x0F, 0xFF},
} }
c := generativeart.NewCanva(800, 800) c := generativeart.NewCanva(800, 800)
c.SetBackground(color.RGBA{0x1a, 0x06, 0x33, 0xFF}) c.SetBackground(color.RGBA{0x1a, 0x06, 0x33, 0xFF})