libcruft-util/noise/lut.hpp

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/*
* This file is part of libgim.
*
* libgim 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.
*
* libgim 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 libgim. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2012 Danny Robson <danny@nerdcruft.net>
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*/
#ifndef __UTIL_NOISE_LUT_HPP
#define __UTIL_NOISE_LUT_HPP
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#include <cstdlib>
#include <type_traits>
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#include "types.hpp"
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namespace util {
namespace noise {
extern const size_t PERM[256];
extern const double LUT [256];
template <typename T>
typename std::enable_if<std::is_integral<T>::value, size_t>::type
permute (T idx) {
return PERM[(size_t)idx % elems (PERM)];
}
template <typename T1, typename T2, typename ...R>
size_t permute (T1 t1, T2 t2, R ...r) {
auto p = permute (t1);
p += permute (t2, r...);
return p % elems (PERM);
}
}
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}
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#endif