libcruft-util/noise/fractal/hmf.ipp

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/*
* 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_HMF_IPP
#error
#endif
#define __UTIL_NOISE_FRACTAL_HMF_IPP
namespace util { namespace noise { namespace fractal {
//-------------------------------------------------------------------------
template <typename T, typename B>
hmf<T,B>::hmf ():
H (0.25f),
octaves (6),
frequency (0.1f),
lacunarity (2),
offset (0.7f),
amplitude (1),
gain (1)
{ ; }
//-------------------------------------------------------------------------
template <typename T, typename B>
T
hmf<T,B>::operator() (util::point<2,T> p) const
{
T exponents[octaves];
for (size_t i = 0; i < octaves; ++i)
exponents[i] = std::pow (std::pow (lacunarity, float (i)), -H);
T result = 0;
T signal = 0;
T weight = 1;
p *= frequency;
for (size_t i = 0; i < octaves; ++i) {
signal = (basis (p) + offset) * exponents[i];
result += weight * signal;
weight *= gain * signal;
if (weight > 1)
weight = 1;
p *= lacunarity;
}
return result;
}
} } }