Initial project import

node_modules/glsl-noise/simplex/2d.glsl

@@ -0,0 +1,72 @@
+//
+// Description : Array and textureless GLSL 2D simplex noise function.
+//      Author : Ian McEwan, Ashima Arts.
+//  Maintainer : ijm
+//     Lastmod : 20110822 (ijm)
+//     License : Copyright (C) 2011 Ashima Arts. All rights reserved.
+//               Distributed under the MIT License. See LICENSE file.
+//               https://github.com/ashima/webgl-noise
+//
+
+vec3 mod289(vec3 x) {
+  return x - floor(x * (1.0 / 289.0)) * 289.0;
+}
+
+vec2 mod289(vec2 x) {
+  return x - floor(x * (1.0 / 289.0)) * 289.0;
+}
+
+vec3 permute(vec3 x) {
+  return mod289(((x*34.0)+1.0)*x);
+}
+
+float snoise(vec2 v)
+  {
+  const vec4 C = vec4(0.211324865405187,  // (3.0-sqrt(3.0))/6.0
+                      0.366025403784439,  // 0.5*(sqrt(3.0)-1.0)
+                     -0.577350269189626,  // -1.0 + 2.0 * C.x
+                      0.024390243902439); // 1.0 / 41.0
+// First corner
+  vec2 i  = floor(v + dot(v, C.yy) );
+  vec2 x0 = v -   i + dot(i, C.xx);
+
+// Other corners
+  vec2 i1;
+  //i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
+  //i1.y = 1.0 - i1.x;
+  i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
+  // x0 = x0 - 0.0 + 0.0 * C.xx ;
+  // x1 = x0 - i1 + 1.0 * C.xx ;
+  // x2 = x0 - 1.0 + 2.0 * C.xx ;
+  vec4 x12 = x0.xyxy + C.xxzz;
+  x12.xy -= i1;
+
+// Permutations
+  i = mod289(i); // Avoid truncation effects in permutation
+  vec3 p = permute( permute( i.y + vec3(0.0, i1.y, 1.0 ))
+    + i.x + vec3(0.0, i1.x, 1.0 ));
+
+  vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);
+  m = m*m ;
+  m = m*m ;
+
+// Gradients: 41 points uniformly over a line, mapped onto a diamond.
+// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)
+
+  vec3 x = 2.0 * fract(p * C.www) - 1.0;
+  vec3 h = abs(x) - 0.5;
+  vec3 ox = floor(x + 0.5);
+  vec3 a0 = x - ox;
+
+// Normalise gradients implicitly by scaling m
+// Approximation of: m *= inversesqrt( a0*a0 + h*h );
+  m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );
+
+// Compute final noise value at P
+  vec3 g;
+  g.x  = a0.x  * x0.x  + h.x  * x0.y;
+  g.yz = a0.yz * x12.xz + h.yz * x12.yw;
+  return 130.0 * dot(m, g);
+}
+
+#pragma glslify: export(snoise)