/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_MATH_NOISE_FBM_HPP
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#define ANTKEEPER_MATH_NOISE_FBM_HPP
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#include "math/hash/make-uint.hpp"
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#include "math/hash/pcg.hpp"
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#include "math/noise/simplex.hpp"
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#include "math/vector.hpp"
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#include <cstdint>
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namespace math {
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namespace noise {
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/**
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* Fractional Brownian motion (fBm).
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*
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* @tparam T Real type.
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* @tparam N Number of dimensions.
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*
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* @param position Input position.
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* @param octaves Number of octaves.
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* @param lacunarity Frequency multiplier.
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* @param gain Amplitude multiplier.
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* @param noise Noise function.
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* @param hash Hash function.
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*
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*/
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template <class T, std::size_t N>
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[[nodiscard]] T fbm
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(
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vector<T, N> position,
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std::size_t octaves,
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T lacunarity,
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T gain,
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T (*noise)(const vector<T, N>&, vector<hash::make_uint_t<T>, N> (*)(const vector<T, N>&)) = &simplex<T, N>,
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vector<hash::make_uint_t<T>, N> (*hash)(const vector<T, N>&) = &hash::pcg<T, N>
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)
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{
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T amplitude{1};
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T value{0};
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while (octaves--)
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{
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value += noise(position, hash) * amplitude;
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position *= lacunarity;
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amplitude *= gain;
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}
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return value;
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}
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} // namespace noise
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} // namespace math
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#endif // ANTKEEPER_MATH_NOISE_FBM_HPP
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