69 lines
2.2 KiB
C++
69 lines
2.2 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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#ifndef __UTIL_NOISE_TURBULENCE_HPP
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#define __UTIL_NOISE_TURBULENCE_HPP
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#include "../point.hpp"
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#include "../vector.hpp"
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#include <cstdint>
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namespace util { namespace noise {
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/// perturb the evaluation point of a noise function by the results of
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/// a per-dimension noise function
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///
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/// assumes the pertubation function is roughly symetrical around 0.
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/// nothing will explode if it isn't, but you'll see strong directional
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/// artefacts with higher scaling factors.
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template <
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typename D, // data fractal
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typename P // pertubation fractal
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>
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struct turbulence {
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using value_t = typename D::value_t;
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using point_t = typename D::point_t;
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using scale_t = vector<point_t::dimension,value_t>;
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static constexpr size_t S = D::point_t::dimension;
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static_assert (std::is_same<typename D::value_t, typename P::value_t>::value,
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"data and perturbation value types must match");
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static_assert (std::is_same<typename D::point_t, typename P::point_t>::value,
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"data and perturbation point types must match");
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turbulence (seed_t, scale_t);
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seed_t seed (seed_t);
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seed_t seed (void) const;
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constexpr value_t operator() (point_t) const;
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D data;
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// XXX: use a union to defer initialization of pertubation fractals in
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// the constructor. i know this is horrible, but there's no time to
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// write the proper generator constructor to pass out the seeds.
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P perturb[S];
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scale_t scale;
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};
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} }
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#include "turbulence.ipp"
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#endif
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