examples/rosettacode/perlin_noise.nit

   1 #!/usr/bin/env nit
   2 #
   3 # This file is part of NIT ( http://www.nitlanguage.org ).
   4 # This program is public domain
   5
   6 # Task: Perlin noise
   7 #
   8 # See: <http://rosettacode.org/wiki/Perlin_noise>
   9 module perlin_noise
  10
  11 redef universal Float
  12         # Smoothened `self`
  13         fun fade: Float do return self*self*self*(self*(self*6.0-15.0)+10.0)
  14 end
  15
  16 # Improved noise
  17 class ImprovedNoise
  18         # Permutations
  19         var p: Array[Int] = [151,160,137,91,90,15,
  20                 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
  21                 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
  22                 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
  23                 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
  24                 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
  25                 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
  26                 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
  27                 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
  28                 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
  29                 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
  30                 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
  31                 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180]
  32
  33         # Noise value in [-1..1] at 3d coordinates `x, y, z`
  34         fun noise(x, y, z: Float): Float
  35         do
  36                 var xx = x.to_i.bin_and(255)
  37                 var yy = y.to_i.bin_and(255)
  38                 var zz = z.to_i.bin_and(255)
  39
  40                 x -= x.floor
  41                 y -= y.floor
  42                 z -= z.floor
  43
  44                 var u = x.fade
  45                 var v = y.fade
  46                 var w = z.fade
  47
  48                 var a  = p[xx  ] + yy
  49                 var aa = p[a   ] + zz
  50                 var ab = p[a+1 ] + zz
  51                 var b  = p[xx+1] + yy
  52                 var ba = p[b   ] + zz
  53                 var bb = p[b+1 ] + zz
  54
  55                 return w.lerp(v.lerp(u.lerp(grad(p[aa  ], x,     y,     z    ),
  56                                             grad(p[ba  ], x-1.0, y,     z    )),
  57                                      u.lerp(grad(p[ab  ], x,     y-1.0, z    ),
  58                                             grad(p[bb  ], x-1.0, y-1.0, z    ))),
  59                       v.lerp(u.lerp(grad(p[aa+1], x,     y,     z-1.0),
  60                                             grad(p[ba+1], x-1.0, y,     z-1.0)),
  61                                      u.lerp(grad(p[ab+1], x,     y-1.0, z-1.0),
  62                                             grad(p[bb+1], x-1.0, y-1.0, z-1.0))))
  63         end
  64
  65         # Value at a corner of the grid
  66         fun grad(hash: Int, x, y, z: Float): Float
  67         do
  68                 var h = hash.bin_and(15)
  69                 var u = if h < 8 then x else y
  70                 var v = if h < 4 then y else if h == 12 or h == 14 then x else z
  71                 return (if h.is_even then u else -u) + (if h.bin_and(2) == 0 then v else -v)
  72         end
  73 end
  74
  75 var map = new ImprovedNoise
  76 print map.noise(3.14, 42.0, 7.0).to_precision(17)