Making spirals more and more wiggly
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// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(1);
const radmax = 38 //min=1 max=100 step=1
const size = 500 //min=0 max=1000 step=1
const spiral_1 = 100 //min=0 max=1000 step=1
const spiral_2 = 0 //min=0 max=10 step=.1
const noise_amp_start = 10 //min=-10 max=100 step=0.1
const noise_freq_inc = 1 //min=0 max=10 step=0.01
const noise_amp_inc = 1 //min=0 max=100 step=0.01
const noise_octives = 1 //min=0 max=10 step=0.1
const noise_shift = 0 //min=-5 max=5 step=0.1
const grid_x = 3 //min=1 max=20 step=1
const grid_y = 3 //min=1 max=20 step=1
const space_x = 66 //min=1 max=200 step=1
const space_y = 66 //min=1 max=200 step=1
const xstart = -66 //min=-200 max=200 step=1
const ystart = -66 //min=-200 max=200 step=1
// Global code will be evaluated once.
const turtle = new Turtle();
turtle.penup();
function fdiff_r(diffx, diffy) {
return Math.sqrt(diffx**2 + diffy**2)
}
let last_x = 0
let last_y = 0
class Noise {
// http://mrl.nyu.edu/~perlin/noise/
constructor(octaves = 1) {
this.p = new Uint8Array(512);
this.octaves = octaves;
for (let i = 0; i < 512; ++i) {
this.p[i] = Math.random() * 256;
}
}
lerp(t, a, b) {
return a + t * (b - a);
}
grad2d(i, x, y) {
const v = (i & 1) === 0 ? x : y;
return (i & 2) === 0 ? -v : v;
}
noise2d(x2d, y2d) {
const X = Math.floor(x2d) & 255;
const Y = Math.floor(y2d) & 255;
const x = x2d - Math.floor(x2d);
const y = y2d - Math.floor(y2d);
const fx = (3 - 2 * x) * x * x;
const fy = (3 - 2 * y) * y * y;
const p0 = this.p[X] + Y;
const p1 = this.p[X + 1] + Y;
return this.lerp(
fy,
this.lerp(
fx,
this.grad2d(this.p[p0], x, y),
this.grad2d(this.p[p1], x - 1, y)
),
this.lerp(
fx,
this.grad2d(this.p[p0 + 1], x, y - 1),
this.grad2d(this.p[p1 + 1], x - 1, y - 1)
)
);
}
noise(x, y) {
let e = 1,
k = 1,
s = 0;
for (let i = 0; i < this.octaves; ++i) {
e *= 0.5;
s += e * (1 + this.noise2d(k * x, k * y)) / 2;
k *= 2;
}
return s;
}
}
let random_walk = 0
function walk(i) {
let max_i = grid_x * grid_y - 1
let x = i%grid_x
let y = Math.floor(i/grid_x)
xpos = x*space_x + xstart
ypos = y*space_y + ystart
dist_to_center = 125 - Math.sqrt((xpos)**2 + (ypos)**2)
noise_freq = i * noise_freq_inc
noise_amp = i * noise_amp_inc
turtle.penup()
spiral(xpos, ypos, noise_freq, noise_amp)
return i<max_i
}
function spiral(xshift, yshift, noise_freq, noise_amp) {
perlin = new Noise(noise_octives/10);
for (let i = 0; i/10000 < Math.PI*radmax; ++i) {
let angle = i/10000
let radius = angle*(spiral_1 + angle*spiral_2)/size
//radius = 50
if (i%5==0) {
random_walk += Math.random()-0.5
}
radius += perlin.noise((radius+10)**2*noise_freq/10, yshift)*noise_amp - noise_shift
let pen_x = radius * Math.cos(angle) + xshift
let pen_y = radius * Math.sin(angle) + yshift
//check for small moves
if (fdiff_r(pen_x-last_x, pen_y-last_y) > .1) {
if ((Math.abs(pen_x)-100 < 0) & (Math.abs(pen_y)-100 < 0)) {
turtle.goto(pen_x, pen_y);
turtle.pendown()
last_x=pen_x
last_y=pen_y
}
}
turtle.pendown()
}
return
}