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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/>.
- */
-
- #include "entity/systems/blackbody.hpp"
- #include "color/color.hpp"
- #include "physics/light/blackbody.hpp"
- #include "physics/light/photometry.hpp"
- #include "math/quadrature.hpp"
-
- namespace entity {
- namespace system {
-
- blackbody::blackbody(entity::registry& registry):
- updatable(registry),
- rgb_wavelengths_nm{0, 0, 0},
- rgb_wavelengths_m{0, 0, 0}
- {
- // Construct a range of sample wavelengths in the visible spectrum
- visible_wavelengths_nm.resize(780 - 280);
- std::iota(visible_wavelengths_nm.begin(), visible_wavelengths_nm.end(), 280);
-
- registry.on_construct<entity::component::blackbody>().connect<&blackbody::on_blackbody_construct>(this);
- registry.on_replace<entity::component::blackbody>().connect<&blackbody::on_blackbody_replace>(this);
-
- registry.on_construct<entity::component::celestial_body>().connect<&blackbody::on_celestial_body_construct>(this);
- registry.on_replace<entity::component::celestial_body>().connect<&blackbody::on_celestial_body_replace>(this);
- }
-
- void blackbody::update(double t, double dt)
- {}
-
- void blackbody::set_rgb_wavelengths(const double3& wavelengths)
- {
- rgb_wavelengths_nm = wavelengths;
- rgb_wavelengths_m = wavelengths * 1e-9;
- }
-
- void blackbody::update_luminous_intensity(entity::id entity_id)
- {
- // Abort if entity has no blackbody component
- if (!registry.has<component::blackbody>(entity_id))
- return;
-
- // Get blackbody component of the entity
- component::blackbody& blackbody = registry.get<component::blackbody>(entity_id);
-
- // Clear luminous intensity
- blackbody.luminous_intensity = {0, 0, 0};
-
- // Abort if entity has no celestial body component
- if (!registry.has<component::celestial_body>(entity_id))
- return;
-
- // Get celestial body component of the entity
- const component::celestial_body& celestial_body = registry.get<component::celestial_body>(entity_id);
-
- // Calculate (spherical) surface area of the celestial body
- const double surface_area = 4.0 * math::pi<double> * celestial_body.radius * celestial_body.radius;
-
- // Construct a lambda function which calculates the blackbody's RGB luminous intensity of a given wavelength
- auto rgb_luminous_intensity = [blackbody, surface_area](double wavelength_nm) -> double3
- {
- // Convert wavelength from nanometers to meters
- const double wavelength_m = wavelength_nm * 1e-9;
-
- // Calculate the spectral intensity of the wavelength
- const double spectral_intensity = physics::light::blackbody::spectral_intensity<double>(blackbody.temperature, surface_area, wavelength_m);
-
- // Calculate the ACEScg color of the wavelength using CIE color matching functions
- double3 spectral_color = color::xyz::to_acescg(color::xyz::match(wavelength_nm));
-
- // Scale the spectral color by spectral intensity
- return spectral_color * spectral_intensity * 1e-9 * physics::light::max_luminous_efficacy<double>;
- };
-
- // Integrate the blackbody RGB luminous intensity over wavelengths in the visible spectrum
- blackbody.luminous_intensity = math::quadrature::simpson(rgb_luminous_intensity, visible_wavelengths_nm.begin(), visible_wavelengths_nm.end());
- }
-
- void blackbody::on_blackbody_construct(entity::registry& registry, entity::id entity_id, entity::component::blackbody& blackbody)
- {
- update_luminous_intensity(entity_id);
- }
-
- void blackbody::on_blackbody_replace(entity::registry& registry, entity::id entity_id, entity::component::blackbody& blackbody)
- {
- update_luminous_intensity(entity_id);
- }
-
- void blackbody::on_celestial_body_construct(entity::registry& registry, entity::id entity_id, entity::component::celestial_body& celestial_body)
- {
- update_luminous_intensity(entity_id);
- }
-
- void blackbody::on_celestial_body_replace(entity::registry& registry, entity::id entity_id, entity::component::celestial_body& celestial_body)
- {
- update_luminous_intensity(entity_id);
- }
-
- } // namespace system
- } // namespace entity
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