💿🐜 Antkeeper source code
https://antkeeper.com
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112 lines
3.2 KiB
112 lines
3.2 KiB
/*
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* Copyright (C) 2021 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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#ifndef ANTKEEPER_ASTRONOMY_SYSTEM_HPP
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#define ANTKEEPER_ASTRONOMY_SYSTEM_HPP
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#include "entity-system.hpp"
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#include "utility/fundamental-types.hpp"
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class sky_pass;
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/**
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* Calculates apparent properties of celestial bodies relative to an observer (magnitude, angular radius, horizontal coordinates) and modifies their model component and/or light component to render them accordingly.
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*/
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class astronomy_system:
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public entity_system
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{
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public:
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astronomy_system(entt::registry& registry);
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/**
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* Scales then adds the timestep `dt` to the current time, then recalculates the positions of celestial bodies.
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*
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* @param t Time, in seconds.
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* @param dt Delta time, in seconds.
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*/
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virtual void update(double t, double dt);
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/**
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* Sets the current universal time.
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*
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* @param time Universal time, in days.
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*/
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void set_universal_time(double time);
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/**
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* Sets the factor by which the timestep `dt` will be scaled before being added to the current universal time.
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*
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* @param scale Factor by which to scale the timestep.
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*/
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void set_time_scale(double scale);
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/**
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* Sets the location of the observer.
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*
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* @param location Spherical coordinates of the observer, in the ISO order of radial distance, polar angle (radians), and azimuthal angle (radians).
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*/
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void set_observer_location(const double3& location);
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/**
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* Sets the obliquity of the ecliptic, a.k.a. axial tilt.
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*
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* @param angle Angle between the planet's rotational axis and its orbital axis, in radians.
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*/
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void set_obliquity(double angle);
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/**
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* Sets the rotational speed of the observer's planet.
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*
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* @param speed Rotational speed, in radians per day.
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*/
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void set_axial_rotation_speed(double speed);
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void set_axial_rotation_at_epoch(double angle);
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void set_sky_pass(::sky_pass* pass);
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void set_sun(entt::entity entity);
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void set_moon(entt::entity entity);
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private:
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/// Updates the axial rotation angle
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void update_axial_rotation();
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/// Updates the local sidereal time (LST) and dependent variables
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void update_sidereal_time();
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/// Updates the ecliptic-to-horizontal transformation matrix
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void update_ecliptic_to_horizontal();
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double universal_time;
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double days_per_timestep;
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double lst;
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double axial_rotation_at_epoch;
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double axial_rotation_speed;
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double axial_rotation;
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double3 observer_location;
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double obliquity;
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double3x3 ecliptic_to_horizontal;
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sky_pass* sky_pass;
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entt::entity sun;
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entt::entity moon;
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};
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#endif // ANTKEEPER_ASTRONOMY_SYSTEM_HPP
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