01 - Perfect loop / Infinite loop / endless GIFs
/*
* A speed-improved perlin and simplex noise algorithms for 2D.
*
* Based on example code by Stefan Gustavson (stegu@itn.liu.se).
* Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
* Better rank ordering method by Stefan Gustavson in 2012.
* Converted to Javascript by Joseph Gentle.
*
* Version 2012-03-09
*
* This code was placed in the public domain by its original author,
* Stefan Gustavson. You may use it as you see fit, but
* attribution is appreciated.
*
*/
(function (global) {
const module = global.noise = {}
function Grad (x, y, z) {
this.x = x
this.y = y
this.z = z
}
Grad.prototype.dot2 = function (x, y) {
return this.x * x + this.y * y
}
Grad.prototype.dot3 = function (x, y, z) {
return this.x * x + this.y * y + this.z * z
}
const grad3 = [new Grad(1, 1, 0), new Grad(-1, 1, 0), new Grad(1, -1, 0), new Grad(-1, -1, 0),
new Grad(1, 0, 1), new Grad(-1, 0, 1), new Grad(1, 0, -1), new Grad(-1, 0, -1),
new Grad(0, 1, 1), new Grad(0, -1, 1), new Grad(0, 1, -1), new Grad(0, -1, -1)
]
const p = [151, 160, 137, 91, 90, 15,
131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21,
10,
23,
190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177,
33,
88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27,
166,
77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40,
244,
102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200,
196,
135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124,
123,
5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189,
28,
42,
223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218, 246, 97,
228,
251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239,
107,
49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254,
138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
]
// To remove the need for index wrapping, double the permutation table length
const perm = new Array(512)
const gradP = new Array(512)
// This isn't a very good seeding function, but it works ok. It supports 2^16
// different seed values. Write something better if you need more seeds.
module.seed = function (seed) {
if (seed > 0 && seed < 1) {
// Scale the seed out
seed *= 65536
}
seed = Math.floor(seed)
if (seed < 256) {
seed |= seed << 8
}
for (let i = 0; i < 256; i++) {
let v
if (i & 1) {
v = p[i] ^ (seed & 255)
} else {
v = p[i] ^ ((seed >> 8) & 255)
}
perm[i] = perm[i + 256] = v
gradP[i] = gradP[i + 256] = grad3[v % 12]
}
}
module.seed(0)
/*
for(var i=0; i<256; i++) {
perm[i] = perm[i + 256] = p[i];
gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
} */
// Skewing and unskewing factors for 2, 3, and 4 dimensions
const F2 = 0.5 * (Math.sqrt(3) - 1)
const G2 = (3 - Math.sqrt(3)) / 6
const F3 = 1 / 3
const G3 = 1 / 6
// 2D simplex noise
module.simplex2 = function (xin, yin) {
let n0, n1, n2 // Noise contributions from the three corners
// Skew the input space to determine which simplex cell we're in
const s = (xin + yin) * F2 // Hairy factor for 2D
let i = Math.floor(xin + s)
let j = Math.floor(yin + s)
const t = (i + j) * G2
const x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
const y0 = yin - j + t
// For the 2D case, the simplex shape is an equilateral triangle.
// Determine which simplex we are in.
let i1, j1 // Offsets for second (middle) corner of simplex in (i,j) coords
if (x0 > y0) { // lower triangle, XY order: (0,0)->(1,0)->(1,1)
i1 = 1
j1 = 0
} else { // upper triangle, YX order: (0,0)->(0,1)->(1,1)
i1 = 0
j1 = 1
}
// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
// c = (3-sqrt(3))/6
const x1 = x0 - i1 + G2 // Offsets for middle corner in (x,y) unskewed coords
const y1 = y0 - j1 + G2
const x2 = x0 - 1 + 2 * G2 // Offsets for last corner in (x,y) unskewed coords
const y2 = y0 - 1 + 2 * G2
// Work out the hashed gradient indices of the three simplex corners
i &= 255
j &= 255
const gi0 = gradP[i + perm[j]]
const gi1 = gradP[i + i1 + perm[j + j1]]
const gi2 = gradP[i + 1 + perm[j + 1]]
// Calculate the contribution from the three corners
let t0 = 0.5 - x0 * x0 - y0 * y0
if (t0 < 0) {
n0 = 0
} else {
t0 *= t0
n0 = t0 * t0 * gi0.dot2(x0, y0) // (x,y) of grad3 used for 2D gradient
}
let t1 = 0.5 - x1 * x1 - y1 * y1
if (t1 < 0) {
n1 = 0
} else {
t1 *= t1
n1 = t1 * t1 * gi1.dot2(x1, y1)
}
let t2 = 0.5 - x2 * x2 - y2 * y2
if (t2 < 0) {
n2 = 0
} else {
t2 *= t2
n2 = t2 * t2 * gi2.dot2(x2, y2)
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 70 * (n0 + n1 + n2)
}
// 3D simplex noise
module.simplex3 = function (xin, yin, zin) {
let n0, n1, n2, n3 // Noise contributions from the four corners
// Skew the input space to determine which simplex cell we're in
const s = (xin + yin + zin) * F3 // Hairy factor for 2D
let i = Math.floor(xin + s)
let j = Math.floor(yin + s)
let k = Math.floor(zin + s)
const t = (i + j + k) * G3
const x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
const y0 = yin - j + t
const z0 = zin - k + t
// For the 3D case, the simplex shape is a slightly irregular tetrahedron.
// Determine which simplex we are in.
let i1, j1, k1 // Offsets for second corner of simplex in (i,j,k) coords
let i2, j2, k2 // Offsets for third corner of simplex in (i,j,k) coords
if (x0 >= y0) {
if (y0 >= z0) {
i1 = 1
j1 = 0
k1 = 0
i2 = 1
j2 = 1
k2 = 0
} else if (x0 >= z0) {
i1 = 1
j1 = 0
k1 = 0
i2 = 1
j2 = 0
k2 = 1
} else {
i1 = 0
j1 = 0
k1 = 1
i2 = 1
j2 = 0
k2 = 1
}
} else {
if (y0 < z0) {
i1 = 0
j1 = 0
k1 = 1
i2 = 0
j2 = 1
k2 = 1
} else if (x0 < z0) {
i1 = 0
j1 = 1
k1 = 0
i2 = 0
j2 = 1
k2 = 1
} else {
i1 = 0
j1 = 1
k1 = 0
i2 = 1
j2 = 1
k2 = 0
}
}
// A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
// a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
// a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
// c = 1/6.
const x1 = x0 - i1 + G3 // Offsets for second corner
const y1 = y0 - j1 + G3
const z1 = z0 - k1 + G3
const x2 = x0 - i2 + 2 * G3 // Offsets for third corner
const y2 = y0 - j2 + 2 * G3
const z2 = z0 - k2 + 2 * G3
const x3 = x0 - 1 + 3 * G3 // Offsets for fourth corner
const y3 = y0 - 1 + 3 * G3
const z3 = z0 - 1 + 3 * G3
// Work out the hashed gradient indices of the four simplex corners
i &= 255
j &= 255
k &= 255
const gi0 = gradP[i + perm[j + perm[k]]]
const gi1 = gradP[i + i1 + perm[j + j1 + perm[k + k1]]]
const gi2 = gradP[i + i2 + perm[j + j2 + perm[k + k2]]]
const gi3 = gradP[i + 1 + perm[j + 1 + perm[k + 1]]]
// Calculate the contribution from the four corners
let t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0
if (t0 < 0) {
n0 = 0
} else {
t0 *= t0
n0 = t0 * t0 * gi0.dot3(x0, y0, z0) // (x,y) of grad3 used for 2D gradient
}
let t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1
if (t1 < 0) {
n1 = 0
} else {
t1 *= t1
n1 = t1 * t1 * gi1.dot3(x1, y1, z1)
}
let t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2
if (t2 < 0) {
n2 = 0
} else {
t2 *= t2
n2 = t2 * t2 * gi2.dot3(x2, y2, z2)
}
let t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3
if (t3 < 0) {
n3 = 0
} else {
t3 *= t3
n3 = t3 * t3 * gi3.dot3(x3, y3, z3)
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 32 * (n0 + n1 + n2 + n3)
}
// ##### Perlin noise stuff
function fade (t) {
return t * t * t * (t * (t * 6 - 15) + 10)
}
function lerp (a, b, t) {
return (1 - t) * a + t * b
}
// 2D Perlin Noise
module.perlin2 = function (x, y) {
// Find unit grid cell containing point
let X = Math.floor(x)
let Y = Math.floor(y)
// Get relative xy coordinates of point within that cell
x = x - X
y = y - Y
// Wrap the integer cells at 255 (smaller integer period can be introduced here)
X = X & 255
Y = Y & 255
// Calculate noise contributions from each of the four corners
const n00 = gradP[X + perm[Y]].dot2(x, y)
const n01 = gradP[X + perm[Y + 1]].dot2(x, y - 1)
const n10 = gradP[X + 1 + perm[Y]].dot2(x - 1, y)
const n11 = gradP[X + 1 + perm[Y + 1]].dot2(x - 1, y - 1)
// Compute the fade curve value for x
const u = fade(x)
// Interpolate the four results
return lerp(
lerp(n00, n10, u),
lerp(n01, n11, u),
fade(y))
}
// 3D Perlin Noise
module.perlin3 = function (x, y, z) {
// Find unit grid cell containing point
let X = Math.floor(x)
let Y = Math.floor(y)
let Z = Math.floor(z)
// Get relative xyz coordinates of point within that cell
x = x - X
y = y - Y
z = z - Z
// Wrap the integer cells at 255 (smaller integer period can be introduced here)
X = X & 255
Y = Y & 255
Z = Z & 255
// Calculate noise contributions from each of the eight corners
const n000 = gradP[X + perm[Y + perm[Z]]].dot3(x, y, z)
const n001 = gradP[X + perm[Y + perm[Z + 1]]].dot3(x, y, z - 1)
const n010 = gradP[X + perm[Y + 1 + perm[Z]]].dot3(x, y - 1, z)
const n011 = gradP[X + perm[Y + 1 + perm[Z + 1]]].dot3(x, y - 1, z - 1)
const n100 = gradP[X + 1 + perm[Y + perm[Z]]].dot3(x - 1, y, z)
const n101 = gradP[X + 1 + perm[Y + perm[Z + 1]]].dot3(x - 1, y, z - 1)
const n110 = gradP[X + 1 + perm[Y + 1 + perm[Z]]].dot3(x - 1, y - 1, z)
const n111 = gradP[X + 1 + perm[Y + 1 + perm[Z + 1]]].dot3(x - 1, y - 1, z - 1)
// Compute the fade curve value for x, y, z
const u = fade(x)
const v = fade(y)
const w = fade(z)
// Interpolate
return lerp(
lerp(
lerp(n000, n100, u),
lerp(n001, n101, u), w),
lerp(
lerp(n010, n110, u),
lerp(n011, n111, u), w),
v)
}
})(this)
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