155 lines
4.1 KiB
C++
155 lines
4.1 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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#include "noise/fractal.hpp"
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#include "debug.hpp"
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#include <algorithm>
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///////////////////////////////////////////////////////////////////////////////
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util::noise::fractal::fractal (unsigned _octaves,
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double _frequency,
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double _lacunarity):
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octaves (_octaves),
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frequency (_frequency),
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lacunarity (_lacunarity)
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{ ; }
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util::noise::fractal::fractal ():
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octaves (1),
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frequency (0.1),
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lacunarity (0.6)
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{ ; }
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util::noise::fractal::~fractal ()
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{ ; }
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double
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util::noise::fractal::eval (double, double) const
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{ unreachable (); }
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///////////////////////////////////////////////////////////////////////////////
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template <typename B>
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util::noise::fbm<B>::fbm (unsigned _octaves,
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double _frequency,
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double _lacunarity,
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basis::seed_t _seed):
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fractal (_octaves, _frequency, _lacunarity),
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basis (_seed)
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{ ; }
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template <typename B>
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util::noise::fbm<B>::fbm ()
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{ ; }
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template <typename B>
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double
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util::noise::fbm<B>::eval (double x, double y) const {
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double total = 0.0;
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double f = this->frequency;
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double a = 1.0;
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double a_sum = 0.0;
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for (size_t i = 0; i < this->octaves; ++i) {
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total += basis.eval (x * f, y * f) * a;
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f *= 2.0;
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a_sum += a;
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a *= this->lacunarity;
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}
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return total;
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}
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template struct util::noise::fbm<util::noise::cellular>;
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template struct util::noise::fbm<util::noise::gradient<lerp::linear>>;
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template struct util::noise::fbm<util::noise::gradient<lerp::quintic>>;
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template struct util::noise::fbm<util::noise::value<lerp::linear>>;
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template struct util::noise::fbm<util::noise::value<lerp::quintic>>;
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///////////////////////////////////////////////////////////////////////////////
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template <typename B>
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util::noise::musgrave<B>::musgrave (unsigned _octaves,
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double _frequency,
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double _lacunarity,
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basis::seed_t _seed):
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fractal (_octaves, _frequency, _lacunarity),
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basis (_seed)
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{ ; }
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template <typename B>
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util::noise::musgrave<B>::musgrave ()
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{ ; }
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template <typename B>
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double
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util::noise::musgrave<B>::eval (double x, double y) const {
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double total = 0.0;
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double f = this->frequency;
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double a = 1.0;
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double weight = 1.0;
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double offset = 1.0;
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double gain = 2.0;
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double signal;
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signal = basis.eval (x * f, y * f);
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signal = fabs (signal);
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signal = offset - signal;
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signal *= signal;
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total = signal;
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for (size_t i = 1; i < this->octaves; ++i) {
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f *= 2.0;
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a *= this->lacunarity;
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weight = signal * gain;
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weight = max (0.0, min (1.0, weight));
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signal = basis.eval (x * f, y * f);
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signal = fabs (signal);
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signal = offset - signal;
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signal *= signal;
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signal *= weight;
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total += signal * a;
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total = min (1.0, max (0.0, total));
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}
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return total;
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}
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template struct util::noise::musgrave<util::noise::cellular>;
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template struct util::noise::musgrave<util::noise::gradient<lerp::linear>>;
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template struct util::noise::musgrave<util::noise::gradient<lerp::quintic>>;
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template struct util::noise::musgrave<util::noise::value<lerp::linear>>;
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template struct util::noise::musgrave<util::noise::value<lerp::quintic>>;
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