/*#***************************************************************************
 * perlin_noise.h                                                   o o      *
 *                                                                o     o    *
 * Visual Computing Group                                         _  O  _    *
 * IEI Institute, CNUCE Institute, CNR Pisa                        \/)\/     *
 *                                                                /\/|       *
 * Copyright(C) 1999 by Paolo Cignoni, Paolo Pingi, Claudio Rocchini |       *
 * All rights reserved.                                              \       *
 *                                                                           *
 * Permission  to use, copy, modify, distribute  and sell this  software and *
 * its documentation for any purpose is hereby granted without fee, provided *
 * that  the above copyright notice appear  in all copies and that both that *
 * copyright   notice  and  this  permission  notice  appear  in  supporting *
 * documentation. the author makes  no representations about the suitability *
 * of this software for any purpose. It is provided  "as is" without express *
 * or implied warranty.                                                      *
 *                                                                           *
 *****************************************************************************/
/****************************************************************************
  History
$Log: not supported by cvs2svn $
 *****************************************************************************/
#ifndef __VCGLIB_PERLIN_NOISE
#define __VCGLIB_PERLIN_NOISE

namespace vcg
{
 namespace math {
// based on the java reference implementation published 
// on http://mrl.nyu.edu/~perlin/noise/
// updated on 13/7/2005


class Perlin 
{
public:

  /// 3D Perlin noise
  /// return a value in the 0..1 range with period 255
   static double Noise(double x, double y, double z) {
      int X = (int)floor(x) & 255,                  // FIND UNIT CUBE THAT
          Y = (int)floor(y) & 255,                  // CONTAINS POINT.
          Z = (int)floor(z) & 255;
      x -= floor(x);                                // FIND RELATIVE X,Y,Z
      y -= floor(y);                                // OF POINT IN CUBE.
      z -= floor(z);
      double u = fade(x),                                // COMPUTE FADE CURVES
             v = fade(y),                                // FOR EACH OF X,Y,Z.
             w = fade(z);
      int A = P(X  )+Y, AA = P(A)+Z, AB = P(A+1)+Z,      // HASH COORDINATES OF
          B = P(X+1)+Y, BA = P(B)+Z, BB = P(B+1)+Z;      // THE 8 CUBE CORNERS,

      return lerp(w, lerp(v, lerp(u, grad(P(AA  ), x  , y  , z   ),  // AND ADD
                                     grad(P(BA  ), x-1, y  , z   )), // BLENDED
                             lerp(u, grad(P(AB  ), x  , y-1, z   ),  // RESULTS
                                     grad(P(BB  ), x-1, y-1, z   ))),// FROM  8
                     lerp(v, lerp(u, grad(P(AA+1), x  , y  , z-1 ),  // CORNERS
                                     grad(P(BA+1), x-1, y  , z-1 )), // OF CUBE
                             lerp(u, grad(P(AB+1), x  , y-1, z-1 ),
                                     grad(P(BB+1), x-1, y-1, z-1 ))));
   }
   static double fade(double t) { return t * t * t * (t * (t * 6 - 15) + 10); }
   static double lerp(double t, double a, double b) { return a + t * (b - a); }
   static double grad(int hash, double x, double y, double z) {
      int h = hash & 15;                      // CONVERT LO 4 BITS OF HASH CODE
      double u = h<8 ? x : y,                 // INTO 12 GRADIENT DIRECTIONS.
             v = h<4 ? y : h==12||h==14 ? x : z;
      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
   }
   static int P(int i)
   {
     static int p[512]= { 151,160,137,91,90,15,
   131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
   190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
   88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
   77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
   102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
   135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
   5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
   223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
   129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
   251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
   49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
   138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180, 
    151,160,137,91,90,15,
   131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
   190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
   88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
   77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
   102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
   135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
   5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
   223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
   129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
   251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
   49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
   138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
   };
   return p[i];
}
};

 } // end namespace
} // end namespace
#endif