167 lines
4.5 KiB
C++
167 lines
4.5 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 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_NOISE_FRACTAL_HPP
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#define __UTIL_NOISE_FRACTAL_HPP
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#include "basis.hpp"
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namespace util {
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namespace noise {
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/// Base noise summation
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template <typename T>
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struct fractal {
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using seed_t = uint64_t;
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fractal (seed_t);
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fractal ();
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virtual ~fractal ();
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virtual T operator() (T x, T y) const = 0;
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seed_t seed;
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};
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/// Fractal Brownian Motion summation.
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///
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/// Sum progressive layers of a noise basis with scaling frequency
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/// and amplitude.
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///
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/// octaves: count of layers to be summed
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/// frequency: point scaling factor for the base octave
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/// lacunarity: per octave frequency scaling factor
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/// amplitude: maximum absolute value of the noise
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/// gain: per octave amplitude scaling factor. typically 1/f.
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template <typename T, typename B>
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struct fbm : public fractal<T> {
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using seed_t = typename basis<T>::seed_t;
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static constexpr unsigned DEFAULT_OCTAVES = 8;
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static constexpr T DEFAULT_FREQUENCY = T(0.1);
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static constexpr T DEFAULT_LACUNARITY = 2;
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static constexpr T DEFAULT_AMPLITUDE = 1;
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static constexpr T DEFAULT_GAIN = 1 / T(2);
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fbm (unsigned octaves,
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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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fbm ();
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unsigned octaves;
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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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B basis;
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virtual T operator() (T x, T y) const override;
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};
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/// Rigid Multifractal summation, based on Musgrave's algorithm
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///
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/// octaves: count of layers to be summed
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/// frequency: point scaling factor for the base octave
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/// lacunarity: per octave frequency scaling factor
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template <typename T, typename B>
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struct rmf : public fractal<T> {
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using seed_t = typename basis<T>::seed_t;
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static constexpr unsigned DEFAULT_OCTAVES = 5;
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static constexpr T DEFAULT_FREQUENCY = T(1);
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static constexpr T DEFAULT_LACUNARITY = 2;
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static constexpr T DEFAULT_AMPLITUDE = 1;
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static constexpr T DEFAULT_GAIN = 2;
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rmf (unsigned octaves,
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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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rmf ();
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unsigned octaves;
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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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B basis;
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virtual T operator() (T x, T y) const override;
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};
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///////////////////////////////////////////////////////////////////////
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template <typename T, typename B>
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struct hmf : public fractal<T> {
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using seed_t = typename basis<T>::seed_t;
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hmf ();
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T H;
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unsigned octaves;
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T frequency;
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T lacunarity;
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T offset;
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T amplitude;
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T gain;
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B basis;
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virtual T operator() (T x, T y) const override;
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};
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///////////////////////////////////////////////////////////////////////
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/// Heterogeneous procedural terrain fucntion: stats by altitude method
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template <typename T, typename B>
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struct hetero : public fractal<T> {
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using seed_t = typename basis<T>::seed_t;
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hetero ();
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T H;
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unsigned octaves;
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T frequency;
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T lacunarity;
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T offset;
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T amplitude;
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T gain;
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B basis;
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virtual T operator() (T x, T y) const override;
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};
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}
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}
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#endif
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