libcruft-util/noise/fractal.hpp

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/*
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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
*
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* 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 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_NOISE_FRACTAL_HPP
#define __UTIL_NOISE_FRACTAL_HPP
#include "basis.hpp"
namespace util {
namespace noise {
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/// Base noise summation
template <typename T>
struct fractal {
using seed_t = uint64_t;
fractal (seed_t);
fractal ();
virtual ~fractal ();
virtual T operator() (T x, T y) const = 0;
seed_t seed;
};
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/// Fractal Brownian Motion summation.
///
/// Sum progressive layers of a noise basis with scaling frequency
/// and amplitude.
///
/// octaves: count of layers to be summed
/// frequency: point scaling factor for the base octave
/// lacunarity: per octave frequency scaling factor
/// amplitude: maximum absolute value of the noise
/// gain: per octave amplitude scaling factor. typically 1/f.
template <typename T, typename B>
struct fbm : public fractal<T> {
using seed_t = typename basis<T>::seed_t;
fbm (unsigned octaves,
T frequency,
T lacunarity,
T amplitude,
T gain,
seed_t seed);
fbm ();
unsigned octaves;
T frequency;
T lacunarity;
T amplitude;
T gain;
B basis;
virtual T operator() (T x, T y) const override;
};
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/// Rigid Multifractal noise summation, based on Musgrave's algorithm
///
/// octaves: count of layers to be summed
/// frequency: point scaling factor for the base octave
/// lacunarity: per octave frequency scaling factor
template <typename T, typename B>
struct rmf : public fractal<T> {
using seed_t = typename basis<T>::seed_t;
rmf (unsigned octaves,
T frequency,
T lacunarity,
T amplitude,
T gain,
seed_t seed);
rmf ();
unsigned octaves;
T frequency;
T lacunarity;
T amplitude;
T gain;
B basis;
virtual T operator() (T x, T y) const override;
};
}
}
#endif