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Added Simplex Noise functions.

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Richard Davey 2017-02-10 01:28:50 +00:00
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v3/src/math/noise/SimplexNoise.js Normal file
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/*
* 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;