// some portions are licensed by:
// Copyright (C) 2011 by Ashima Arts (Simplex noise)
// Copyright (C) 2011 by Stefan Gustavson (Classic noise)
//
// 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 ShaderLib = {};

  ShaderLib.noise3d = [
  '//',
  '// Description : Array and textureless GLSL 2D/3D/4D simplex ',
  '//               noise functions.',
  '//      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;',
  '}',
  '',
  'vec4 mod289(vec4 x) {',
  '  return x - floor(x * (1.0 / 289.0)) * 289.0;',
  '}',
  '',
  'vec4 permute(vec4 x) {',
  '     return mod289(((x*34.0)+1.0)*x);',
  '}',
  '',
  'vec4 taylorInvSqrt(vec4 r)',
  '{',
  '  return 1.79284291400159 - 0.85373472095314 * r;',
  '}',
  '',
  'float snoise(vec3 v)',
  '{',
  '  const vec2  C = vec2(1.0/6.0, 1.0/3.0) ;',
  '  const vec4  D = vec4(0.0, 0.5, 1.0, 2.0);',
  '',
  '// First corner',
  '  vec3 i  = floor(v + dot(v, C.yyy) );',
  '  vec3 x0 =   v - i + dot(i, C.xxx) ;',
  '',
  '// Other corners',
  '  vec3 g = step(x0.yzx, x0.xyz);',
  '  vec3 l = 1.0 - g;',
  '  vec3 i1 = min( g.xyz, l.zxy );',
  '  vec3 i2 = max( g.xyz, l.zxy );',
  '',
  '  //   x0 = x0 - 0.0 + 0.0 * C.xxx;',
  '  //   x1 = x0 - i1  + 1.0 * C.xxx;',
  '  //   x2 = x0 - i2  + 2.0 * C.xxx;',
  '  //   x3 = x0 - 1.0 + 3.0 * C.xxx;',
  '  vec3 x1 = x0 - i1 + C.xxx;',
  '  vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y',
  '  vec3 x3 = x0 - D.yyy;      // -1.0+3.0*C.x = -0.5 = -D.y',
  '',
  '// Permutations',
  '  i = mod289(i); ',
  '  vec4 p = permute( permute( permute( ',
  '             i.z + vec4(0.0, i1.z, i2.z, 1.0 ))',
  '           + i.y + vec4(0.0, i1.y, i2.y, 1.0 )) ',
  '           + i.x + vec4(0.0, i1.x, i2.x, 1.0 ));',
  '',
  '// Gradients: 7x7 points over a square, mapped onto an octahedron.',
  '// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)',
  '  float n_ = 0.142857142857; // 1.0/7.0',
  '  vec3  ns = n_ * D.wyz - D.xzx;',
  '',
  '  vec4 j = p - 49.0 * floor(p * ns.z * ns.z);  //  mod(p,7*7)',
  '',
  '  vec4 x_ = floor(j * ns.z);',
  '  vec4 y_ = floor(j - 7.0 * x_ );    // mod(j,N)',
  '',
  '  vec4 x = x_ *ns.x + ns.yyyy;',
  '  vec4 y = y_ *ns.x + ns.yyyy;',
  '  vec4 h = 1.0 - abs(x) - abs(y);',
  '',
  '  vec4 b0 = vec4( x.xy, y.xy );',
  '  vec4 b1 = vec4( x.zw, y.zw );',
  '',
  '  //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;',
  '  //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;',
  '  vec4 s0 = floor(b0)*2.0 + 1.0;',
  '  vec4 s1 = floor(b1)*2.0 + 1.0;',
  '  vec4 sh = -step(h, vec4(0.0));',
  '',
  '  vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;',
  '  vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;',
  '',
  '  vec3 p0 = vec3(a0.xy,h.x);',
  '  vec3 p1 = vec3(a0.zw,h.y);',
  '  vec3 p2 = vec3(a1.xy,h.z);',
  '  vec3 p3 = vec3(a1.zw,h.w);',
  '',
  '//Normalise gradients',
  '  vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));',
  '  p0 *= norm.x;',
  '  p1 *= norm.y;',
  '  p2 *= norm.z;',
  '  p3 *= norm.w;',
  '',
  '// Mix final noise value',
  '  vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);',
  '  m = m * m;',
  '  return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), ',
  '                                dot(p2,x2), dot(p3,x3) ) );',
  '}'].join('\n');

  ShaderLib.noise2d = [
  '//',
  '// 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);',
  '}'].join('\n');

module.exports = ShaderLib;
