💿🐜 Antkeeper source code
https://antkeeper.com
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79 lines
2.0 KiB
79 lines
2.0 KiB
/*
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* Copyright (C) 2021 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_PHYSICS_LIGHT_VMAG_HPP
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#define ANTKEEPER_PHYSICS_LIGHT_VMAG_HPP
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#include <cmath>
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namespace physics {
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namespace light {
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/// Apparent (visual) magnitude functions.
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namespace vmag {
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/**
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* Converts apparent magnitude to a brightness factor relative to a 0th magnitude star.
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*
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* @param mv Apparent magnitude.
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* @return Brightness factor relative to a 0th magnitude star.
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*
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* @see https://en.wikipedia.org/wiki/Illuminance
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*/
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template <class T>
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T to_brightness(T mv)
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{
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// 100^(1/5)
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static constexpr double fifth_root_100 = 2.5118864315095801110850320677993;
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return std::pow(fifth_root_100, -mv);
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}
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/**
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* Converts apparent magnitude to illuminance.
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*
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* @param mv Apparent magnitude.
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* @return Illuminance, in lux.
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*
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* @see https://en.wikipedia.org/wiki/Illuminance
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*/
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template <class T>
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T to_illuminance(T mv)
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{
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return std::pow(10.0, (-14.18 - mv) * 0.4);
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}
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/**
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* Converts illuminance to apparent magnitude.
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*
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* @param ev Illuminance, in lux.
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* @return Apparent magnitude.
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*
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* @see https://en.wikipedia.org/wiki/Illuminance
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*/
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template <class T>
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T from_illuminance(T ev)
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{
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return -14.18 - 2.5 * std::log10(ev);
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}
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} // namespace vmag
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} // namespace light
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} // namespace physics
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#endif // ANTKEEPER_PHYSICS_LIGHT_VMAG_HPP
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