103 lines
2.9 KiB
C++
103 lines
2.9 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2012-2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifdef __UTIL_NOISE_FRACTAL_RMF_IPP
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#error
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#endif
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#define __UTIL_NOISE_FRACTAL_RMF_IPP
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namespace util { namespace noise { namespace fractal {
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///////////////////////////////////////////////////////////////////////////
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template <typename T, typename B>
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rmf<T,B>::rmf (unsigned _octaves,
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T _H,
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T _offset,
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T _frequency,
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T _lacunarity,
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T _amplitude,
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T _gain,
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seed_t _seed):
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seed (_seed),
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octaves (_octaves),
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H (_H),
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offset (_offset),
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frequency (_frequency),
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lacunarity (_lacunarity),
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amplitude (_amplitude),
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gain (_gain),
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basis (_seed),
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invAH (std::pow (amplitude, -H)),
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invGH (std::pow (gain, H))
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{ ; }
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//-------------------------------------------------------------------------
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template <typename T, typename B>
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rmf<T,B>::rmf ():
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rmf<T,B> (DEFAULT_OCTAVES,
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DEFAULT_H,
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DEFAULT_OFFSET,
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DEFAULT_FREQUENCY,
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DEFAULT_LACUNARITY,
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DEFAULT_AMPLITUDE,
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DEFAULT_GAIN,
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rand ())
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{ ; }
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//-------------------------------------------------------------------------
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// we use the name 'amplitude' instead of musgrave's 'gain'.
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// assumes basis distribution [-1,1] and offset ~= 1
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template <typename T, typename B>
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constexpr T
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rmf<T,B>::operator() (util::point<2,T> p) const
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{
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T scale = invAH;
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T signal = 0;
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T result = 0;
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T weight = 1;
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p *= frequency;
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for (size_t i = 0; i < octaves; ++i) {
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// generates ridged noise
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signal = basis (p);
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signal = std::fabs (signal);
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signal = offset - signal;
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// sharpens the ridges
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signal *= signal;
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// influence by sharpness of previous iteration
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signal *= weight;
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// contribute to the weight
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weight = signal * amplitude;
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weight = limit (weight, 0, 1);
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// record and continue
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result += signal * scale;
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scale *= invGH;
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p *= lacunarity;
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}
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return result;
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}
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} } }
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