/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#ifndef NOISE_H_
#define NOISE_H_

#include "global.h"

template<int N, typename T = float>
struct gen_vec_base
{
  enum { D = N };
  T v[N];

  T &operator [](int n)
  {
    return v[n];
  }

  template<typename U>
  const gen_vec_base<N,T> &operator =(gen_vec_base<N,U> v)
  {
    for (int i = 0; i < N; ++i)
      this->v[i] = v.v[i];

    return *this;
  }
};

template<int N, typename T>
gen_vec_base<N,T> floor (gen_vec_base<N,T> v)
{
  for (int i = 0; i < N; ++i)
    v[i] = floor (v[i]);

  return v;
}

template<int N, typename T, typename U>
gen_vec_base<N,T> operator +(gen_vec_base<N,T> a, gen_vec_base<N,U> b)
{
  gen_vec_base<N,T> c;

  for (int i = 0; i < N; ++i)
    c[i] = a[i] + b[i];

  return c;
}

template<int N, typename T, typename U>
gen_vec_base<N,T> operator -(gen_vec_base<N,T> a, gen_vec_base<N,U> b)
{
  gen_vec_base<N,T> c;

  for (int i = 0; i < N; ++i)
    c[i] = a[i] - b[i];

  return c;
}

template<int N, typename T, typename U>
T operator *(gen_vec_base<N,T> a, gen_vec_base<N,U> b)
{
  T v = 0;

  for (int i = 0; i < N; ++i)
    v += a[i] * b[i];

  return v;
}

template<int N, typename T = float>
struct gen_vec;

template<typename T>
struct gen_vec<2,T> : gen_vec_base<2,T>
{
  using gen_vec_base<2,T>::operator =;

  gen_vec ()
  {
  }

  gen_vec (T x, T y)
  {
    this->v[0] = x;
    this->v[1] = y;
  }

  template<typename U>
  gen_vec (gen_vec_base<2,U> v)
  {
    *this = v;
  }
};

template<typename T>
struct gen_vec<3,T> : gen_vec_base<3,T>
{
  gen_vec ()
  {
  }

  gen_vec (T x, T y, T z)
  {
    this->v[0] = x;
    this->v[1] = y;
    this->v[2] = z;
  }

  template<typename U>
  gen_vec (gen_vec_base<3,U> v)
  {
    *this = v;
  }
};

typedef gen_vec<2> vec2d;
typedef gen_vec<3> vec3d;

template<int N, typename T = float>
struct space
{
  enum { D = N };
  typedef gen_vec<N,T> vec;
};

typedef space<2> space2d;
typedef space<3> space3d;

/////////////////////////////////////////////////////////////////////////////

template<int N, typename T = uint8_t>
struct permutation
{
  T pmap [N];

  template<class generator>
  void seed (generator &rng)
  {
    for (int i = 0; i < N; ++i)
      pmap [i] = i;

    // fisher-yates to randomly perturb
    for (int i = N; --i; )
      ::swap (pmap [i], pmap [::rmg_rndm (i + 1)]);
  }

  T operator ()(T v)
  {
    return pmap [v & (N - 1)];
  }
};

// modelled after 2d/3d kensler noise without projection
struct noise2d
{
  permutation<256, uint8_t> rvmap[2];
  float rvec [256][2]; // random unit vectors

  noise2d (uint32_t seed);
  float noise (float x, float y);
};

struct noise3d
{
  permutation<256, uint8_t> rvmap[3];
  float rvec [256][3]; // random unit vectors

  noise3d (uint32_t seed);
  float noise (float x, float y, float z);

  // noise projected on a surface with normal n
  float noise (float x, float y, float z, float nx, float ny, float nz);
};

struct rotate
{
  float s, c;

  void set (float angle)
  {
    s = sinf (angle);
    c = cosf (angle);
  }

  void operator ()(float &x, float &y) const
  {
    float xr = x * c - y * s;
    float yr = x * s + y * c;

    x = xr;
    y = yr;
  }
};

struct frac_gen
: noise2d
{
  enum { MAX_OCTAVES = 64 };

  float h, lac, ex [MAX_OCTAVES];
  float fbm_mul [MAX_OCTAVES];
  rotate rot [MAX_OCTAVES];

  frac_gen (float hurst_expo = .5f, float lacunarity = 2.f);

  float fBm (float x, float y, int octaves);
  float turbulence (float x, float y, int octaves);
  float multifractal (float x, float y, int octaves, float offset = 1);
  float heterofractal (float x, float y, int octaves, float offset = 1);
  float hybridfractal (float x, float y, int octaves, float offset = 1, float gain = 1);
  float terrain (float x, float y, int octaves);
  float terrain2 (float x, float y, int octaves);
  float ridgedmultifractal (float x, float y, int octaves, float offset = 1, float gain = 8);
};

#endif