libcruft-util/noise/fractal.cpp

208 lines
6.2 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2012 Danny Robson <danny@nerdcruft.net>
*/
#include "noise/fractal.hpp"
#include "debug.hpp"
#include <algorithm>
#include <cmath>
using util::noise::fractal;
using util::noise::fbm;
using util::noise::rmf;
///////////////////////////////////////////////////////////////////////////////
template <typename T>
fractal<T>::fractal ():
seed (rand ())
{ ; }
//-----------------------------------------------------------------------------
template <typename T>
fractal<T>::fractal (seed_t _seed):
seed (_seed)
{ ; }
//-----------------------------------------------------------------------------
template <typename T>
fractal<T>::~fractal ()
{ ; }
//-----------------------------------------------------------------------------
template <typename T>
T
fractal<T>::operator() (T, T) const
{
unreachable ();
}
//-----------------------------------------------------------------------------
namespace util { namespace noise {
template struct fractal<float>;
template struct fractal<double>;
} }
///////////////////////////////////////////////////////////////////////////////
template <typename T, typename B>
fbm<T,B>::fbm (unsigned _octaves,
T _frequency,
T _lacunarity,
T _amplitude,
T _gain,
seed_t _seed):
fractal<T> (_seed),
octaves (_octaves),
frequency (_frequency),
lacunarity (_lacunarity),
amplitude (_amplitude),
gain (_gain),
basis (_seed)
{
CHECK_NEQ (octaves, 0);
CHECK_NEQ (frequency, 0);
CHECK_NEQ (amplitude, 0);
}
//-----------------------------------------------------------------------------
template <typename T, typename B>
fbm<T,B>::fbm ():
fbm<T,B> (8, T(0.1), 2, 1, 1/T(2), rand ())
{ ; }
//-----------------------------------------------------------------------------
template <typename T, typename B>
T
fbm<T,B>::operator() (T x, T y) const {
T total = 0;
T f = frequency;
T a = amplitude;
for (size_t i = 0; i < octaves; ++i) {
total += basis (x * f, y * f) * a;
f *= lacunarity;
a *= gain;
}
return total;
}
//-----------------------------------------------------------------------------
template struct util::noise::fbm<float, util::noise::cellular<float>>;
template struct util::noise::fbm<float, util::noise::gradient<float,util::lerp::linear>>;
template struct util::noise::fbm<float, util::noise::gradient<float,util::lerp::quintic>>;
template struct util::noise::fbm<float, util::noise::value<float,util::lerp::trunc>>;
template struct util::noise::fbm<float, util::noise::value<float,util::lerp::linear>>;
template struct util::noise::fbm<float, util::noise::value<float,util::lerp::quintic>>;
template struct util::noise::fbm<double, util::noise::cellular<double>>;
template struct util::noise::fbm<double, util::noise::gradient<double,util::lerp::linear>>;
template struct util::noise::fbm<double, util::noise::gradient<double,util::lerp::quintic>>;
template struct util::noise::fbm<double, util::noise::value<double,util::lerp::trunc>>;
template struct util::noise::fbm<double, util::noise::value<double,util::lerp::linear>>;
template struct util::noise::fbm<double, util::noise::value<double,util::lerp::quintic>>;
///////////////////////////////////////////////////////////////////////////////
template <typename T, typename B>
rmf<T,B>::rmf (unsigned _octaves,
T _frequency,
T _lacunarity,
T _amplitude,
T _gain,
seed_t _seed):
fractal<T> (_seed),
octaves (_octaves),
frequency (_frequency),
lacunarity (_lacunarity),
amplitude (_amplitude),
gain (_gain),
basis (_seed)
{ ; }
//-----------------------------------------------------------------------------
template <typename T, typename B>
rmf<T,B>::rmf ():
rmf<T,B> (6, T(1), 2, 1, T(2), rand ())
{ ; }
//-----------------------------------------------------------------------------
template <typename T, typename B>
T
rmf<T,B>::operator() (T x, T y) const {
T H = 1;
T exponents[octaves];
T offset = 1;
T f = 1.f;
for (size_t i = 0; i < octaves; ++i) {
exponents[i] = std::pow (f, -H);
f *= lacunarity;
}
T signal = 0, result = 0, weight = 1;
x *= frequency;
y *= frequency;
for (size_t i = 0; i < octaves; ++i) {
signal = basis (x, y);
signal = std::fabs (signal);
signal = offset - signal;
signal *= signal;
signal *= weight;
weight = signal * gain;
weight = limit (weight, 0, 1);
result += signal * exponents[i];
x *= lacunarity;
y *= lacunarity;
}
return result;
}
//-----------------------------------------------------------------------------
template struct util::noise::rmf<float, util::noise::cellular<float>>;
template struct util::noise::rmf<float, util::noise::gradient<float,util::lerp::linear>>;
template struct util::noise::rmf<float, util::noise::gradient<float,util::lerp::quintic>>;
template struct util::noise::rmf<float, util::noise::value<float,util::lerp::linear>>;
template struct util::noise::rmf<float, util::noise::value<float,util::lerp::quintic>>;
template struct util::noise::rmf<double, util::noise::cellular<double>>;
template struct util::noise::rmf<double, util::noise::gradient<double,util::lerp::linear>>;
template struct util::noise::rmf<double, util::noise::gradient<double,util::lerp::quintic>>;
template struct util::noise::rmf<double, util::noise::value<double,util::lerp::linear>>;
template struct util::noise::rmf<double, util::noise::value<double,util::lerp::quintic>>;