perlin.js 9.7 KB

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  1. (function(global){
  2. var module = global.noise = {};
  3. function Grad(x, y, z) {
  4. this.x = x; this.y = y; this.z = z;
  5. }
  6. Grad.prototype.dot2 = function(x, y) {
  7. return this.x*x + this.y*y;
  8. };
  9. Grad.prototype.dot3 = function(x, y, z) {
  10. return this.x*x + this.y*y + this.z*z;
  11. };
  12. var grad3 = [new Grad(1,1,0),new Grad(-1,1,0),new Grad(1,-1,0),new Grad(-1,-1,0),
  13. new Grad(1,0,1),new Grad(-1,0,1),new Grad(1,0,-1),new Grad(-1,0,-1),
  14. new Grad(0,1,1),new Grad(0,-1,1),new Grad(0,1,-1),new Grad(0,-1,-1)];
  15. var p = [151,160,137,91,90,15,
  16. 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
  17. 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
  18. 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
  19. 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
  20. 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
  21. 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
  22. 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
  23. 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
  24. 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
  25. 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
  26. 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
  27. 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180];
  28. // To remove the need for index wrapping, double the permutation table length
  29. var perm = new Array(512);
  30. var gradP = new Array(512);
  31. // This isn't a very good seeding function, but it works ok. It supports 2^16
  32. // different seed values. Write something better if you need more seeds.
  33. module.seed = function(seed) {
  34. if(seed > 0 && seed < 1) {
  35. // Scale the seed out
  36. seed *= 65536;
  37. }
  38. seed = Math.floor(seed);
  39. if(seed < 256) {
  40. seed |= seed << 8;
  41. }
  42. for(var i = 0; i < 256; i++) {
  43. var v;
  44. if (i & 1) {
  45. v = p[i] ^ (seed & 255);
  46. } else {
  47. v = p[i] ^ ((seed>>8) & 255);
  48. }
  49. perm[i] = perm[i + 256] = v;
  50. gradP[i] = gradP[i + 256] = grad3[v % 12];
  51. }
  52. };
  53. module.seed(0);
  54. /*
  55. for(var i=0; i<256; i++) {
  56. perm[i] = perm[i + 256] = p[i];
  57. gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
  58. }*/
  59. // Skewing and unskewing factors for 2, 3, and 4 dimensions
  60. var F2 = 0.5*(Math.sqrt(3)-1);
  61. var G2 = (3-Math.sqrt(3))/6;
  62. var F3 = 1/3;
  63. var G3 = 1/6;
  64. // 2D simplex noise
  65. module.simplex2 = function(xin, yin) {
  66. var n0, n1, n2; // Noise contributions from the three corners
  67. // Skew the input space to determine which simplex cell we're in
  68. var s = (xin+yin)*F2; // Hairy factor for 2D
  69. var i = Math.floor(xin+s);
  70. var j = Math.floor(yin+s);
  71. var t = (i+j)*G2;
  72. var x0 = xin-i+t; // The x,y distances from the cell origin, unskewed.
  73. var y0 = yin-j+t;
  74. // For the 2D case, the simplex shape is an equilateral triangle.
  75. // Determine which simplex we are in.
  76. var i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
  77. if(x0>y0) { // lower triangle, XY order: (0,0)->(1,0)->(1,1)
  78. i1=1; j1=0;
  79. } else { // upper triangle, YX order: (0,0)->(0,1)->(1,1)
  80. i1=0; j1=1;
  81. }
  82. // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
  83. // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
  84. // c = (3-sqrt(3))/6
  85. var x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
  86. var y1 = y0 - j1 + G2;
  87. var x2 = x0 - 1 + 2 * G2; // Offsets for last corner in (x,y) unskewed coords
  88. var y2 = y0 - 1 + 2 * G2;
  89. // Work out the hashed gradient indices of the three simplex corners
  90. i &= 255;
  91. j &= 255;
  92. var gi0 = gradP[i+perm[j]];
  93. var gi1 = gradP[i+i1+perm[j+j1]];
  94. var gi2 = gradP[i+1+perm[j+1]];
  95. // Calculate the contribution from the three corners
  96. var t0 = 0.5 - x0*x0-y0*y0;
  97. if(t0<0) {
  98. n0 = 0;
  99. } else {
  100. t0 *= t0;
  101. n0 = t0 * t0 * gi0.dot2(x0, y0); // (x,y) of grad3 used for 2D gradient
  102. }
  103. var t1 = 0.5 - x1*x1-y1*y1;
  104. if(t1<0) {
  105. n1 = 0;
  106. } else {
  107. t1 *= t1;
  108. n1 = t1 * t1 * gi1.dot2(x1, y1);
  109. }
  110. var t2 = 0.5 - x2*x2-y2*y2;
  111. if(t2<0) {
  112. n2 = 0;
  113. } else {
  114. t2 *= t2;
  115. n2 = t2 * t2 * gi2.dot2(x2, y2);
  116. }
  117. // Add contributions from each corner to get the final noise value.
  118. // The result is scaled to return values in the interval [-1,1].
  119. return 70 * (n0 + n1 + n2);
  120. };
  121. // 3D simplex noise
  122. module.simplex3 = function(xin, yin, zin) {
  123. var n0, n1, n2, n3; // Noise contributions from the four corners
  124. // Skew the input space to determine which simplex cell we're in
  125. var s = (xin+yin+zin)*F3; // Hairy factor for 2D
  126. var i = Math.floor(xin+s);
  127. var j = Math.floor(yin+s);
  128. var k = Math.floor(zin+s);
  129. var t = (i+j+k)*G3;
  130. var x0 = xin-i+t; // The x,y distances from the cell origin, unskewed.
  131. var y0 = yin-j+t;
  132. var z0 = zin-k+t;
  133. // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
  134. // Determine which simplex we are in.
  135. var i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
  136. var i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
  137. if(x0 >= y0) {
  138. if(y0 >= z0) { i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; }
  139. else if(x0 >= z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; }
  140. else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; }
  141. } else {
  142. if(y0 < z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; }
  143. else if(x0 < z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; }
  144. else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; }
  145. }
  146. // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
  147. // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
  148. // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
  149. // c = 1/6.
  150. var x1 = x0 - i1 + G3; // Offsets for second corner
  151. var y1 = y0 - j1 + G3;
  152. var z1 = z0 - k1 + G3;
  153. var x2 = x0 - i2 + 2 * G3; // Offsets for third corner
  154. var y2 = y0 - j2 + 2 * G3;
  155. var z2 = z0 - k2 + 2 * G3;
  156. var x3 = x0 - 1 + 3 * G3; // Offsets for fourth corner
  157. var y3 = y0 - 1 + 3 * G3;
  158. var z3 = z0 - 1 + 3 * G3;
  159. // Work out the hashed gradient indices of the four simplex corners
  160. i &= 255;
  161. j &= 255;
  162. k &= 255;
  163. var gi0 = gradP[i+ perm[j+ perm[k ]]];
  164. var gi1 = gradP[i+i1+perm[j+j1+perm[k+k1]]];
  165. var gi2 = gradP[i+i2+perm[j+j2+perm[k+k2]]];
  166. var gi3 = gradP[i+ 1+perm[j+ 1+perm[k+ 1]]];
  167. // Calculate the contribution from the four corners
  168. var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0;
  169. if(t0<0) {
  170. n0 = 0;
  171. } else {
  172. t0 *= t0;
  173. n0 = t0 * t0 * gi0.dot3(x0, y0, z0); // (x,y) of grad3 used for 2D gradient
  174. }
  175. var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1;
  176. if(t1<0) {
  177. n1 = 0;
  178. } else {
  179. t1 *= t1;
  180. n1 = t1 * t1 * gi1.dot3(x1, y1, z1);
  181. }
  182. var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2;
  183. if(t2<0) {
  184. n2 = 0;
  185. } else {
  186. t2 *= t2;
  187. n2 = t2 * t2 * gi2.dot3(x2, y2, z2);
  188. }
  189. var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3;
  190. if(t3<0) {
  191. n3 = 0;
  192. } else {
  193. t3 *= t3;
  194. n3 = t3 * t3 * gi3.dot3(x3, y3, z3);
  195. }
  196. // Add contributions from each corner to get the final noise value.
  197. // The result is scaled to return values in the interval [-1,1].
  198. return 32 * (n0 + n1 + n2 + n3);
  199. };
  200. // ##### Perlin noise stuff
  201. function fade(t) {
  202. return t*t*t*(t*(t*6-15)+10);
  203. }
  204. function lerp(a, b, t) {
  205. return (1-t)*a + t*b;
  206. }
  207. // 2D Perlin Noise
  208. module.perlin2 = function(x, y) {
  209. // Find unit grid cell containing point
  210. var X = Math.floor(x), Y = Math.floor(y);
  211. // Get relative xy coordinates of point within that cell
  212. x = x - X; y = y - Y;
  213. // Wrap the integer cells at 255 (smaller integer period can be introduced here)
  214. X = X & 255; Y = Y & 255;
  215. // Calculate noise contributions from each of the four corners
  216. var n00 = gradP[X+perm[Y]].dot2(x, y);
  217. var n01 = gradP[X+perm[Y+1]].dot2(x, y-1);
  218. var n10 = gradP[X+1+perm[Y]].dot2(x-1, y);
  219. var n11 = gradP[X+1+perm[Y+1]].dot2(x-1, y-1);
  220. // Compute the fade curve value for x
  221. var u = fade(x);
  222. // Interpolate the four results
  223. return lerp(
  224. lerp(n00, n10, u),
  225. lerp(n01, n11, u),
  226. fade(y));
  227. };
  228. // 3D Perlin Noise
  229. module.perlin3 = function(x, y, z) {
  230. // Find unit grid cell containing point
  231. var X = Math.floor(x), Y = Math.floor(y), Z = Math.floor(z);
  232. // Get relative xyz coordinates of point within that cell
  233. x = x - X; y = y - Y; z = z - Z;
  234. // Wrap the integer cells at 255 (smaller integer period can be introduced here)
  235. X = X & 255; Y = Y & 255; Z = Z & 255;
  236. // Calculate noise contributions from each of the eight corners
  237. var n000 = gradP[X+ perm[Y+ perm[Z ]]].dot3(x, y, z);
  238. var n001 = gradP[X+ perm[Y+ perm[Z+1]]].dot3(x, y, z-1);
  239. var n010 = gradP[X+ perm[Y+1+perm[Z ]]].dot3(x, y-1, z);
  240. var n011 = gradP[X+ perm[Y+1+perm[Z+1]]].dot3(x, y-1, z-1);
  241. var n100 = gradP[X+1+perm[Y+ perm[Z ]]].dot3(x-1, y, z);
  242. var n101 = gradP[X+1+perm[Y+ perm[Z+1]]].dot3(x-1, y, z-1);
  243. var n110 = gradP[X+1+perm[Y+1+perm[Z ]]].dot3(x-1, y-1, z);
  244. var n111 = gradP[X+1+perm[Y+1+perm[Z+1]]].dot3(x-1, y-1, z-1);
  245. // Compute the fade curve value for x, y, z
  246. var u = fade(x);
  247. var v = fade(y);
  248. var w = fade(z);
  249. // Interpolate
  250. return lerp(
  251. lerp(
  252. lerp(n000, n100, u),
  253. lerp(n001, n101, u), w),
  254. lerp(
  255. lerp(n010, n110, u),
  256. lerp(n011, n111, u), w),
  257. v);
  258. };
  259. })(this);