💿🐜 Antkeeper source code
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89 lines
3.6 KiB
89 lines
3.6 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/blackbody-system.hpp"
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#include <engine/physics/light/blackbody.hpp>
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#include <engine/physics/light/photometry.hpp>
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#include <engine/math/quadrature.hpp>
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#include <engine/config.hpp>
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#include <engine/color/xyz.hpp>
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#include <numeric>
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blackbody_system::blackbody_system(entity::registry& registry):
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updatable_system(registry)
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{
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// Construct a range of sample wavelengths in the visible spectrum
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m_visible_wavelengths_nm.resize(780 - 280);
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std::iota(m_visible_wavelengths_nm.begin(), m_visible_wavelengths_nm.end(), 280);
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registry.on_construct<::blackbody_component>().connect<&blackbody_system::on_blackbody_construct>(this);
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registry.on_update<::blackbody_component>().connect<&blackbody_system::on_blackbody_update>(this);
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}
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blackbody_system::~blackbody_system()
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{
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registry.on_construct<::blackbody_component>().disconnect<&blackbody_system::on_blackbody_construct>(this);
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registry.on_update<::blackbody_component>().disconnect<&blackbody_system::on_blackbody_update>(this);
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}
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void blackbody_system::update(float t, float dt)
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{}
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void blackbody_system::update_blackbody(entity::id entity_id)
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{
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// Get blackbody component
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auto& blackbody = registry.get<blackbody_component>(entity_id);
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// Construct a lambda function which calculates the blackbody's RGB luminance of a given wavelength
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auto rgb_spectral_luminance = [&](double wavelength_nm) -> math::dvec3
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{
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// Convert wavelength from nanometers to meters
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const double wavelength_m = wavelength_nm * 1e-9;
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// Calculate the spectral radiance of the wavelength
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const double spectral_radiance = physics::light::blackbody::spectral_radiance<double>(blackbody.temperature, wavelength_m);
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// Convert spectral radiance to spectral luminance
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const double spectral_luminance = spectral_radiance * 1e-9 * physics::light::max_luminous_efficacy<double>;
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// Calculate the XYZ color of the wavelength using CIE color matching functions then transform to RGB
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const auto color_xyz = color::xyz_match(wavelength_nm);
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const auto color_rgb = config::scene_linear_color_space<double>.from_xyz * color_xyz;
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// Scale RGB color by spectral luminance
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return color_rgb * spectral_luminance;
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};
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// Integrate the blackbody RGB spectral luminance over wavelengths in the visible spectrum
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const math::dvec3 rgb_luminance = math::quadrature::simpson(rgb_spectral_luminance, m_visible_wavelengths_nm.begin(), m_visible_wavelengths_nm.end());
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// Extract luminance and color from RGB luminance
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blackbody.luminance = math::max(rgb_luminance);
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blackbody.color = rgb_luminance / blackbody.luminance;
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}
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void blackbody_system::on_blackbody_construct(entity::registry& registry, entity::id entity_id)
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{
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update_blackbody(entity_id);
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}
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void blackbody_system::on_blackbody_update(entity::registry& registry, entity::id entity_id)
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{
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update_blackbody(entity_id);
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}
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