libcruft-util/noise/fractal/fbm.ipp

83 lines
2.4 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 2012-2015 Danny Robson <danny@nerdcruft.net>
*/
#ifdef __UTIL_NOISE_FRACTAL_FBM_IPP
#error
#endif
#define __UTIL_NOISE_FRACTAL_FBM_IPP
#include "../../debug.hpp"
namespace util { namespace noise { namespace fractal {
///////////////////////////////////////////////////////////////////////////
template <typename T, typename B>
fbm<T,B>::fbm (unsigned _octaves,
T _H,
T _frequency,
T _lacunarity,
T _amplitude,
T _gain,
seed_t _seed):
seed (_seed),
octaves (_octaves),
H (_H),
frequency (_frequency),
lacunarity (_lacunarity),
amplitude (_amplitude),
gain (_gain),
basis (_seed),
invAH (std::pow (amplitude, -H)),
invGH (std::pow (gain, H))
{
CHECK_NEQ (octaves, 0);
CHECK_NEQ (frequency, 0);
CHECK_NEQ (amplitude, 0);
}
//-------------------------------------------------------------------------
template <typename T, typename B>
fbm<T,B>::fbm ():
fbm<T,B> (DEFAULT_OCTAVES,
DEFAULT_H,
DEFAULT_FREQUENCY,
DEFAULT_LACUNARITY,
DEFAULT_AMPLITUDE,
DEFAULT_GAIN,
rand ())
{ ; }
//-------------------------------------------------------------------------
template <typename T, typename B>
constexpr T
fbm<T,B>::operator() (util::point<2,T> p) const
{
T total = 0;
T f = frequency;
T a = invAH;
for (size_t i = 0; i < octaves; ++i) {
total += basis (p * f) * a;
f *= lacunarity;
a *= invGH;
}
return total;
}
} } }