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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_MATH_NOISE_FBM_HPP
- #define ANTKEEPER_MATH_NOISE_FBM_HPP
-
- #include "math/vector.hpp"
- #include <functional>
-
- namespace math {
- namespace noise {
-
- /**
- * Fractional Brownian motion (fBm).
- *
- * @tparam T Real type.
- * @tparam N Number of dimensions.
- *
- * @param x n-dimensional input value.
- * @param octaves Number of octaves.
- * @param lacunarity Frequency multiplier.
- * @param gain Amplitude multiplier.
- * @param noise Noise function.
- * @param hash Hash function.
- *
- */
- template <class T, std::size_t N>
- T fbm
- (
- vector<T, N> x,
- std::size_t octaves,
- T lacunarity,
- T gain,
- T (*noise)(const vector<T, N>&, std::uint32_t (*)(const vector<T, N>&)),
- std::uint32_t (*hash)(const vector<T, N>&)
- )
- {
- T amplitude{1};
- T value{0};
-
- while (octaves--)
- {
- value += noise(x, hash) * amplitude;
- x *= lacunarity;
- amplitude *= gain;
- }
-
- return value;
- }
-
- } // namespace noise
- } // namespace math
-
- #endif // ANTKEEPER_MATH_NOISE_FBM_HPP
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