💿🐜 Antkeeper source code
https://antkeeper.com
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172 lines
6.2 KiB
172 lines
6.2 KiB
/*
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* Copyright (C) 2023 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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#include "game/systems/atmosphere-system.hpp"
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#include <engine/physics/gas/atmosphere.hpp>
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#include <engine/physics/gas/ozone.hpp>
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#include <engine/physics/number-density.hpp>
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atmosphere_system::atmosphere_system(entity::registry& registry):
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updatable_system(registry)
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{
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registry.on_construct<::atmosphere_component>().connect<&atmosphere_system::on_atmosphere_construct>(this);
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registry.on_update<::atmosphere_component>().connect<&atmosphere_system::on_atmosphere_update>(this);
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registry.on_destroy<::atmosphere_component>().connect<&atmosphere_system::on_atmosphere_destroy>(this);
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set_rgb_wavelengths({680, 550, 440});
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}
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atmosphere_system::~atmosphere_system()
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{
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registry.on_construct<::atmosphere_component>().disconnect<&atmosphere_system::on_atmosphere_construct>(this);
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registry.on_update<::atmosphere_component>().disconnect<&atmosphere_system::on_atmosphere_update>(this);
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registry.on_destroy<::atmosphere_component>().disconnect<&atmosphere_system::on_atmosphere_destroy>(this);
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}
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void atmosphere_system::update(float t, float dt)
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{}
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void atmosphere_system::set_rgb_wavelengths(const math::dvec3& wavelengths)
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{
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m_rgb_wavelengths_nm = wavelengths;
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m_rgb_wavelengths_m = m_rgb_wavelengths_nm * 1e-9;
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// Update ozone cross sections
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m_rgb_ozone_cross_sections =
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{
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physics::gas::ozone::cross_section_293k<double>(m_rgb_wavelengths_nm.x()),
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physics::gas::ozone::cross_section_293k<double>(m_rgb_wavelengths_nm.y()),
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physics::gas::ozone::cross_section_293k<double>(m_rgb_wavelengths_nm.z())
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};
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// Update atmosphere components
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registry.view<::atmosphere_component>().each
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(
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[&](entity::id entity_id, auto& component)
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{
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update_atmosphere(entity_id);
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}
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);
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}
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void atmosphere_system::set_sky_pass(::render::sky_pass* pass)
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{
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m_sky_pass = pass;
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update_sky_pass();
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}
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void atmosphere_system::set_active_atmosphere(entity::id entity_id)
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{
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if (entity_id != m_active_atmosphere_eid)
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{
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m_active_atmosphere_eid = entity_id;
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update_sky_pass();
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}
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}
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void atmosphere_system::update_atmosphere(entity::id entity_id)
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{
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// Get atmosphere component of the entity
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::atmosphere_component* component = registry.try_get<::atmosphere_component>(entity_id);
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// Abort if entity has no atmosphere component
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if (!component)
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{
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return;
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}
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// Calculate Rayleigh scattering coefficients
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const double rayleigh_density = physics::number_density(component->rayleigh_concentration);
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const double rayleigh_polarization = physics::gas::atmosphere::polarization(component->index_of_refraction, rayleigh_density);
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component->rayleigh_scattering =
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{
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physics::gas::atmosphere::scattering(rayleigh_density, rayleigh_polarization, m_rgb_wavelengths_m.x()),
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physics::gas::atmosphere::scattering(rayleigh_density, rayleigh_polarization, m_rgb_wavelengths_m.y()),
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physics::gas::atmosphere::scattering(rayleigh_density, rayleigh_polarization, m_rgb_wavelengths_m.z())
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};
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// Calculate Mie scattering and extinction coefficients
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const double mie_density = physics::number_density(component->mie_concentration);
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const double mie_polarization = physics::gas::atmosphere::polarization(component->index_of_refraction, mie_density);
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component->mie_scattering = physics::gas::atmosphere::scattering(mie_density, mie_polarization);
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component->mie_extinction = physics::gas::atmosphere::extinction(component->mie_scattering, component->mie_albedo);
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// Calculate ozone absorption coefficients
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const double ozone_density = physics::number_density(component->ozone_concentration);
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component->ozone_absorption =
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{
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physics::gas::ozone::absorption(m_rgb_ozone_cross_sections.x(), ozone_density),
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physics::gas::ozone::absorption(m_rgb_ozone_cross_sections.y(), ozone_density),
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physics::gas::ozone::absorption(m_rgb_ozone_cross_sections.z(), ozone_density)
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};
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// Update sky pass parameters
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if (entity_id == m_active_atmosphere_eid)
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{
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update_sky_pass();
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}
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}
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void atmosphere_system::update_sky_pass()
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{
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// Abort if no sky pass set
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if (!m_sky_pass)
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{
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return;
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}
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// Abort if active atmosphere entity is not valid
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if (!registry.valid(m_active_atmosphere_eid))
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{
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return;
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}
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// Get atmosphere component of the entity
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::atmosphere_component* component = registry.try_get<::atmosphere_component>(m_active_atmosphere_eid);
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// Abort if entity has no atmosphere component
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if (!component)
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{
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return;
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}
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m_sky_pass->set_atmosphere_upper_limit(static_cast<float>(component->upper_limit));
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m_sky_pass->set_rayleigh_parameters(static_cast<float>(component->rayleigh_scale_height), math::fvec3(component->rayleigh_scattering));
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m_sky_pass->set_mie_parameters(static_cast<float>(component->mie_scale_height), static_cast<float>(component->mie_scattering), static_cast<float>(component->mie_extinction), static_cast<float>(component->mie_anisotropy));
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m_sky_pass->set_ozone_parameters(static_cast<float>(component->ozone_lower_limit), static_cast<float>(component->ozone_upper_limit), static_cast<float>(component->ozone_mode), math::fvec3(component->ozone_absorption));
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m_sky_pass->set_airglow_luminance(math::fvec3(component->airglow_luminance));
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}
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void atmosphere_system::on_atmosphere_construct(entity::registry& registry, entity::id entity_id)
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{
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update_atmosphere(entity_id);
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}
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void atmosphere_system::on_atmosphere_update(entity::registry& registry, entity::id entity_id)
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{
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update_atmosphere(entity_id);
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}
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void atmosphere_system::on_atmosphere_destroy(entity::registry& registry, entity::id entity_id)
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{
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if (entity_id == m_active_atmosphere_eid)
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{
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m_active_atmosphere_eid = entt::null;
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}
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}
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