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- /**********************************************************************************/
- /**********************************************************************************/
- /*
- * 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){
- var 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;
- };
- var 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)];
- var 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
- var perm = new Array(512);
- var 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(var i = 0; i < 256; i++) {
- var 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(Date.now());
- //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
- var F2 = 0.5*(Math.sqrt(3)-1);
- var G2 = (3-Math.sqrt(3))/6;
- var F3 = 1/3;
- var G3 = 1/6;
- // 2D simplex noise
- module.simplex2 = function(xin, yin) {
- var n0, n1, n2; // Noise contributions from the three corners
- // Skew the input space to determine which simplex cell we're in
- var s = (xin+yin)*F2; // Hairy factor for 2D
- var i = Math.floor(xin+s);
- var j = Math.floor(yin+s);
- var t = (i+j)*G2;
- var x0 = xin-i+t; // The x,y distances from the cell origin, unskewed.
- var y0 = yin-j+t;
- // For the 2D case, the simplex shape is an equilateral triangle.
- // Determine which simplex we are in.
- var 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
- var x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
- var y1 = y0 - j1 + G2;
- var x2 = x0 - 1 + 2 * G2; // Offsets for last corner in (x,y) unskewed coords
- var y2 = y0 - 1 + 2 * G2;
- // Work out the hashed gradient indices of the three simplex corners
- i &= 255;
- j &= 255;
- var gi0 = gradP[i+perm[j]];
- var gi1 = gradP[i+i1+perm[j+j1]];
- var gi2 = gradP[i+1+perm[j+1]];
- // Calculate the contribution from the three corners
- var 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
- }
- var t1 = 0.5 - x1*x1-y1*y1;
- if(t1<0) {
- n1 = 0;
- } else {
- t1 *= t1;
- n1 = t1 * t1 * gi1.dot2(x1, y1);
- }
- var 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);
- };
- })(this);
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