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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code 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.
- *
- * Antkeeper source code 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 Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_PHYSICS_LIGHT_BLACKBODY_HPP
- #define ANTKEEPER_PHYSICS_LIGHT_BLACKBODY_HPP
-
- #include "math/constants.hpp"
- #include "physics/constants.hpp"
-
- namespace physics {
- namespace light {
-
- /**
- * Blackbody radiation functions.
- *
- * @see https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law
- */
- namespace blackbody {
-
- /**
- * Calculates the radiant exitance of a blackbody.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @return Radiant exitance of the blackbody, in watt per square meter.
- */
- template <class T>
- T radiant_exitance(T t);
-
- /**
- * Calculates the radiant flux of a blackbody.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param a Surface area of the blackbody, in square meters.
- * @return Radiant flux of the blackbody, in watt.
- */
- template <class T>
- T radiant_flux(T t, T a);
-
- /**
- * Calculates the radiant intensity of a blackbody.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param a Surface area of the blackbody, in square meters.
- * @return Radiant intensity of the blackbody, in watt per steradian.
- */
- template <class T>
- T radiant_intensity(T t, T a);
-
- /**
- * Calculates the spectral exitance of a blackbody for the given wavelength.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param lambda Wavelength of light, in meters.
- * @param c Speed of light in medium.
- * @return Spectral exitance, in watt per square meter, per meter.
- */
- template <class T>
- T spectral_exitance(T t, T lambda, T c = constants::speed_of_light<T>);
-
- /**
- * Calculates the spectral flux of a blackbody for the given wavelength.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param a Surface area of the blackbody, in square meters.
- * @param lambda Wavelength of light, in meters.
- * @param c Speed of light in medium.
- * @return Spectral flux of the blackbody, in watt per meter.
- */
- template <class T>
- T spectral_flux(T t, T a, T lambda, T c = constants::speed_of_light<T>);
-
- /**
- * Calculates the spectral intensity of a blackbody for the given wavelength.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param a Surface area of the blackbody, in square meters.
- * @param lambda Wavelength of light, in meters.
- * @param c Speed of light in medium.
- * @return Spectral intensity of the blackbody for the given wavelength, in watt per steradian per meter.
- */
- template <class T>
- T spectral_intensity(T t, T a, T lambda, T c = constants::speed_of_light<T>);
-
- /**
- * Calculates the spectral radiance of a blackbody for the given wavelength.
- *
- * @param t Temperature of the blackbody, in kelvin.
- * @param lambda Wavelength of light, in meters.
- * @param c Speed of light in medium.
- * @return Spectral radiance, in watt per steradian per square meter per meter.
- */
- template <class T>
- T spectral_radiance(T t, T lambda, T c = constants::speed_of_light<T>);
-
- template <class T>
- T radiant_exitance(T t)
- {
- const T tt = t * t;
- return constants::stefan_boltzmann<T> * (tt * tt);
- }
-
- template <class T>
- T radiant_flux(T t, T a)
- {
- return a * radiant_exitance(t);
- }
-
- template <class T>
- T radiant_intensity(T t, T a)
- {
- return radiant_flux(t, a) / (T(4) * math::pi<T>);
- }
-
- template <class T>
- T spectral_exitance(T t, T lambda, T c)
- {
- const T hc = constants::planck<T> * c;
- const T lambda2 = lambda * lambda;
-
- // First radiation constant (c1)
- const T c1 = T(2) * math::pi<T> * hc * c;
-
- // Second radiation constant (c2)
- const T c2 = hc / constants::boltzmann<T>;
-
- return (c1 / (lambda2 * lambda2 * lambda)) / std::expm1(c2 / (lambda * t));
- }
-
- template <class T>
- T spectral_flux(T t, T a, T lambda, T c)
- {
- return a * spectral_exitance(t, lambda, c);
- }
-
- template <class T>
- T spectral_intensity(T t, T a, T lambda, T c)
- {
- return spectral_flux(t, a, lambda, c) / (T(4) * math::pi<T>);
- }
-
- template <class T>
- T spectral_radiance(T t, T lambda, T c)
- {
- const T hc = constants::planck<T> * c;
- const T lambda2 = lambda * lambda;
-
- // First radiation constant (c1L)
- const T c1l = T(2) * hc * c;
-
- // Second radiation constant (c2)
- const T c2 = hc / constants::boltzmann<T>;
-
- return (c1l / (lambda2 * lambda2 * lambda)) / std::expm1(c2 / (lambda * t));
- }
-
- } // namespace blackbody
-
- } // namespace light
- } // namespace physics
-
- #endif // ANTKEEPER_PHYSICS_LIGHT_BLACKBODY_HPP
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