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// You can find the Turtle API reference here: https://turtletoy.net/syntax Canvas.setpenopacity(1); const noise = SimplexNoise(Math.random()*1000); // Global code will be evaluated once. const turtle1 = new Turtle(); let size = 1; // The walk function will be called until it returns false. function walk(i) { turtle1.penup(); for (let r=0; r<2*Math.PI+0.01; r+=0.01) { let x = Math.sin(r); let y = Math.cos(r); let distortion = noise.noise2D([x*2,y]); //console.log(distortion); x *= size+(distortion*size/10); y *= size+(distortion*size/10); turtle1.goto(x, y); turtle1.pendown(); } size += (50-i)/15; return i<50; } //////////////////////////////////////////////////////////////// // Simplex Noise utility code. Created by Reinder Nijhoff 2020 // https://turtletoy.net/turtle/6e4e06d42e // Based on: http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf //////////////////////////////////////////////////////////////// function SimplexNoise(seed = 1) { const grad = [ [1, 1, 0], [-1, 1, 0], [1, -1, 0], [-1, -1, 0], [1, 0, 1], [-1, 0, 1], [1, 0, -1], [-1, 0, -1], [0, 1, 1], [0, -1, 1], [0, 1, -1], [0, -1, -1] ]; const perm = new Uint8Array(512); const F2 = (Math.sqrt(3) - 1) / 2, F3 = 1/3; const G2 = (3 - Math.sqrt(3)) / 6, G3 = 1/6; const dot2 = (a, b) => a[0] * b[0] + a[1] * b[1]; const sub2 = (a, b) => [a[0] - b[0], a[1] - b[1]]; const dot3 = (a, b) => a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; const sub3 = (a, b) => [a[0] - b[0], a[1] - b[1], a[2] - b[2]]; class SimplexNoise { constructor(seed = 1) { for (let i = 0; i < 512; i++) { perm[i] = i & 255; } for (let i = 0; i < 255; i++) { const r = (seed = this.hash(i+seed)) % (256 - i) + i; const swp = perm[i]; perm[i + 256] = perm[i] = perm[r]; perm[r + 256] = perm[r] = swp; } } noise2D(p) { const s = dot2(p, [F2, F2]); const c = [Math.floor(p[0] + s), Math.floor(p[1] + s)]; const i = c[0] & 255, j = c[1] & 255; const t = dot2(c, [G2, G2]); const p0 = sub2(p, sub2(c, [t, t])); const o = p0[0] > p0[1] ? [1, 0] : [0, 1]; const p1 = sub2(sub2(p0, o), [-G2, -G2]); const p2 = sub2(p0, [1-2*G2, 1-2*G2]); let n = Math.max(0, 0.5-dot2(p0, p0))**4 * dot2(grad[perm[i+perm[j]] % 12], p0); n += Math.max(0, 0.5-dot2(p1, p1))**4 * dot2(grad[perm[i+o[0]+perm[j+o[1]]] % 12], p1); n += Math.max(0, 0.5-dot2(p2, p2))**4 * dot2(grad[perm[i+1+perm[j+1]] % 12], p2); return 70 * n; } hash(i) { i = 1103515245 * ((i >> 1) ^ i); const h32 = 1103515245 * (i ^ (i>>3)); return h32 ^ (h32 >> 16); } } return new SimplexNoise(seed); }