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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/atmosphere.hpp"
- #include "physics/atmosphere.hpp"
-
- namespace entity {
- namespace system {
-
- atmosphere::atmosphere(entity::registry& registry):
- updatable(registry),
- rgb_wavelengths_nm{0, 0, 0},
- rgb_wavelengths_m{0, 0, 0}
- {
- registry.on_construct<entity::component::atmosphere>().connect<&atmosphere::on_atmosphere_construct>(this);
- registry.on_replace<entity::component::atmosphere>().connect<&atmosphere::on_atmosphere_replace>(this);
- }
-
- void atmosphere::update(double t, double dt)
- {}
-
- void atmosphere::set_rgb_wavelengths(const double3& wavelengths)
- {
- rgb_wavelengths_nm = wavelengths;
- rgb_wavelengths_m = wavelengths * 1e-9;
- }
-
- void atmosphere::update_coefficients(entity::id entity_id)
- {
- // Abort if entity has no atmosphere component
- if (!registry.has<component::atmosphere>(entity_id))
- return;
-
- // Get atmosphere component of the entity
- component::atmosphere& atmosphere = registry.get<component::atmosphere>(entity_id);
-
- // Calculate polarization factors
- const double rayleigh_polarization = physics::atmosphere::polarization(atmosphere.index_of_refraction, atmosphere.rayleigh_density);
- const double mie_polarization = physics::atmosphere::polarization(atmosphere.index_of_refraction, atmosphere.mie_density);
-
- // Calculate Rayleigh scattering coefficients
- atmosphere.rayleigh_scattering =
- {
- physics::atmosphere::scattering_rayleigh(rgb_wavelengths_m.x, atmosphere.rayleigh_density, rayleigh_polarization),
- physics::atmosphere::scattering_rayleigh(rgb_wavelengths_m.y, atmosphere.rayleigh_density, rayleigh_polarization),
- physics::atmosphere::scattering_rayleigh(rgb_wavelengths_m.z, atmosphere.rayleigh_density, rayleigh_polarization)
- };
-
- // Calculate Mie scattering coefficients
- const double mie_scattering = physics::atmosphere::scattering_mie(atmosphere.mie_density, mie_polarization);
- atmosphere.mie_scattering =
- {
- mie_scattering,
- mie_scattering,
- mie_scattering
- };
- }
-
- void atmosphere::on_atmosphere_construct(entity::registry& registry, entity::id entity_id, entity::component::atmosphere& atmosphere)
- {
- update_coefficients(entity_id);
- }
-
- void atmosphere::on_atmosphere_replace(entity::registry& registry, entity::id entity_id, entity::component::atmosphere& atmosphere)
- {
- update_coefficients(entity_id);
- }
-
- } // namespace system
- } // namespace entity
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