From 3e3b327bda41ac1287ff8eebba5808f38d6d7f7f Mon Sep 17 00:00:00 2001 From: Richard Davey Date: Fri, 10 Feb 2017 01:28:50 +0000 Subject: [PATCH] Added Simplex Noise functions. --- v3/src/math/noise/SimplexNoise.js | 163 ++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 v3/src/math/noise/SimplexNoise.js diff --git a/v3/src/math/noise/SimplexNoise.js b/v3/src/math/noise/SimplexNoise.js new file mode 100644 index 000000000..f6e8f52b8 --- /dev/null +++ b/v3/src/math/noise/SimplexNoise.js @@ -0,0 +1,163 @@ +/* + * A fast javascript implementation of simplex noise by Jonas Wagner + * + * Based on a speed-improved simplex noise algorithm for 2D, 3D and 4D in Java. + * Which is based on example code by Stefan Gustavson (stegu@itn.liu.se). + * With Optimisations by Peter Eastman (peastman@drizzle.stanford.edu). + * Better rank ordering method by Stefan Gustavson in 2012. + * + * + * Copyright (C) 2016 Jonas Wagner + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + */ + +var F2 = 0.5 * (Math.sqrt(3.0) - 1.0); +var G2 = (3.0 - Math.sqrt(3.0)) / 6.0; + +function buildPermutationTable (random) +{ + var i; + var p = new Uint8Array(256); + + for (i = 0; i < 256; i++) + { + p[i] = i; + } + + for (i = 0; i < 255; i++) + { + var r = i + ~~(random() * (256 - i)); + var aux = p[i]; + p[i] = p[r]; + p[r] = aux; + } + + return p; +} + +var SimplexNoise = function (random) +{ + if (!random) { random = Math.random; } + + this.p = buildPermutationTable(random); + this.perm = new Uint8Array(512); + this.permMod12 = new Uint8Array(512); + + for (var i = 0; i < 512; i++) + { + this.perm[i] = this.p[i & 255]; + this.permMod12[i] = this.perm[i] % 12; + } +}; + +SimplexNoise.prototype.constructor = SimplexNoise; + +SimplexNoise.prototype = { + + grad3: new Float32Array( + [ 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 ]), + + noise2D: function (xin, yin) + { + var permMod12 = this.permMod12; + var perm = this.perm; + var grad3 = this.grad3; + var n0 = 0; // Noise contributions from the three corners + var n1 = 0; + var n2 = 0; + + // 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 = i - t; // Unskew the cell origin back to (x,y) space + var Y0 = j - t; + var x0 = xin - X0; // The x,y distances from the cell origin + var y0 = yin - Y0; + + // 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 - 1.0 + 2.0 * G2; // Offsets for last corner in (x,y) unskewed coords + var y2 = y0 - 1.0 + 2.0 * G2; + + // Work out the hashed gradient indices of the three simplex corners + var ii = i & 255; + var jj = j & 255; + + // Calculate the contribution from the three corners + var t0 = 0.5 - x0 * x0 - y0 * y0; + + if (t0 >= 0) + { + var gi0 = permMod12[ii + perm[jj]] * 3; + t0 *= t0; + n0 = t0 * t0 * (grad3[gi0] * x0 + grad3[gi0 + 1] * y0); // (x,y) of grad3 used for 2D gradient + } + + var t1 = 0.5 - x1 * x1 - y1 * y1; + + if (t1 >= 0) + { + var gi1 = permMod12[ii + i1 + perm[jj + j1]] * 3; + t1 *= t1; + n1 = t1 * t1 * (grad3[gi1] * x1 + grad3[gi1 + 1] * y1); + } + + var t2 = 0.5 - x2 * x2 - y2 * y2; + + if (t2 >= 0) + { + var gi2 = permMod12[ii + 1 + perm[jj + 1]] * 3; + t2 *= t2; + n2 = t2 * t2 * (grad3[gi2] * x2 + grad3[gi2 + 1] * 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 70.0 * (n0 + n1 + n2); + } +}; + +module.exports = SimplexNoise;