Added Simplex Noise functions.

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;