Browse Source

Add celestial time functions

master
C. J. Howard 1 year ago
parent
commit
1ef5ff08b0
10 changed files with 318 additions and 237 deletions
  1. +0
    -1
      CMakeLists.txt
  2. +12
    -12
      src/game/astronomy/celestial-coordinates.cpp
  3. +16
    -8
      src/game/astronomy/celestial-coordinates.hpp
  4. +104
    -0
      src/game/astronomy/celestial-mechanics.cpp
  5. +32
    -0
      src/game/astronomy/celestial-mechanics.hpp
  6. +62
    -0
      src/game/astronomy/celestial-time.cpp
  7. +66
    -0
      src/game/astronomy/celestial-time.hpp
  8. +9
    -9
      src/game/states/play-state.cpp
  9. +16
    -206
      src/game/systems/weather-system.cpp
  10. +1
    -1
      src/game/systems/weather-system.hpp

+ 0
- 1
CMakeLists.txt View File

@ -4,7 +4,6 @@ option(VERSION_STRING "Project version string" "0.0.0")
project(antkeeper VERSION ${VERSION_STRING} LANGUAGES CXX)
# Find dependency packages
find_package(dr_wav REQUIRED CONFIG)
find_package(stb REQUIRED CONFIG)

+ 12
- 12
src/game/astronomy/celestial-coordinates.cpp View File

@ -58,14 +58,14 @@ double3x3 ecliptic_to_equatorial(double ecl)
};
}
double3x3 ecliptic_to_horizontal(double ecl, double lat, double lst)
double3x3 ecliptic_to_horizontal(double ecl, double lat, double lmst)
{
const double c_ecl = std::cos(ecl);
const double s_ecl = std::sin(ecl);
const double c_lat = std::cos(lat);
const double s_lat = std::sin(lat);
const double c_lst = std::cos(lst);
const double s_lst = std::sin(lst);
const double c_lst = std::cos(lmst);
const double s_lst = std::sin(lmst);
return double3x3
{
@ -88,12 +88,12 @@ double3x3 equatorial_to_ecliptic(double ecl)
};
}
double3x3 equatorial_to_horizontal(double lat, double lst)
double3x3 equatorial_to_horizontal(double lat, double lmst)
{
const double c_lat = std::cos(lat);
const double s_lat = std::sin(lat);
const double c_lst = std::cos(lst);
const double s_lst = std::sin(lst);
const double c_lst = std::cos(lmst);
const double s_lst = std::sin(lmst);
return double3x3
{
@ -103,12 +103,12 @@ double3x3 equatorial_to_horizontal(double lat, double lst)
};
}
double3x3 horizontal_to_equatorial(double lat, double lst)
double3x3 horizontal_to_equatorial(double lat, double lmst)
{
const double c_lat = std::cos(lat);
const double s_lat = std::sin(lat);
const double c_lst = std::cos(lst);
const double s_lst = std::sin(lst);
const double c_lst = std::cos(lmst);
const double s_lst = std::sin(lmst);
return double3x3
{
@ -118,14 +118,14 @@ double3x3 horizontal_to_equatorial(double lat, double lst)
};
}
double3x3 horizontal_to_ecliptic(double ecl, double lat, double lst)
double3x3 horizontal_to_ecliptic(double ecl, double lat, double lmst)
{
const double c_ecl = std::cos(ecl);
const double s_ecl = std::sin(ecl);
const double c_lat = std::cos(lat);
const double s_lat = std::sin(lat);
const double c_lst = std::cos(lst);
const double s_lst = std::sin(lst);
const double c_lst = std::cos(lmst);
const double s_lst = std::sin(lmst);
return double3x3
{

+ 16
- 8
src/game/astronomy/celestial-coordinates.hpp View File

@ -54,10 +54,10 @@ double3x3 ecliptic_to_equatorial(double ecl);
*
* @param ecl Obliquity of the ecliptic, in radians.
* @param lat Observer's latitude, in radians.
* @param lst Local sidereal time.
* @param lmst Local mean sidereal time.
* @return Transformation matrix.
*/
double3x3 ecliptic_to_horizontal(double ecl, double lat, double lst);
double3x3 ecliptic_to_horizontal(double ecl, double lat, double lmst);
/**
* Produces a matrix which transforms rectangular coordinates from equatorial space to ecliptic space.
@ -71,29 +71,37 @@ double3x3 equatorial_to_ecliptic(double ecl);
* Produces a matrix which transforms rectangular coordinates from equatorial space to horizontal space.
*
* @param lat Observer's latitude, in radians.
* @param lst Local sidereal time.
* @param lmst Local mean sidereal time.
* @return Transformation matrix.
*/
double3x3 equatorial_to_horizontal(double lat, double lst);
double3x3 equatorial_to_horizontal(double lat, double lmst);
/**
* Produces a matrix which transforms rectangular coordinates from horizontal space to equatorial space.
*
* @param lat Observer's latitude, in radians.
* @param lst Local sidereal time.
* @param lmst Local mean sidereal time.
* @return Transformation matrix.
*/
double3x3 horizontal_to_equatorial(double lat, double lst);
double3x3 horizontal_to_equatorial(double lat, double lmst);
/**
* Produces a matrix which transforms rectangular coordinates from horizontal space to ecliptic space.
*
* @param ecl Obliquity of the ecliptic, in radians.
* @param lat Observer's latitude, in radians.
* @param lst Local sidereal time.
* @param lmst Local mean sidereal time.
* @return Transformation matrix.
*/
double3x3 horizontal_to_ecliptic(double ecl, double lat, double lst);
double3x3 horizontal_to_ecliptic(double ecl, double lat, double lmst);
/// Matrix which transforms coordinates from horizontal space to a right-handed coordinate system.
constexpr double3x3 horizontal_to_right_handed =
{
0.0, 0.0, 1.0,
1.0, 0.0, 0.0,
0.0, -1.0, 0.0
};
} // namespace ast

+ 104
- 0
src/game/astronomy/celestial-mechanics.cpp View File

@ -18,11 +18,115 @@
*/
#include "celestial-mechanics.hpp"
#include "math/angles.hpp"
#include <cmath>
namespace ast
{
double approx_ecliptic_obliquity(double jd)
{
return math::radians<double>(23.4393 - 3.563e-7 * (jd - 2451545.0));
}
double3 approx_sun_ecliptic(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double m = 6.24 + 628.302 * t;
const double longitude = 4.895048 + 628.331951 * t + (0.033417 - 0.000084 * t) * std::sin(m) + 0.000351 * std::sin(m * 2.0);
const double latitude = 0.0;
const double distance = 1.000140 - (0.016708 - 0.000042 * t) * std::cos(m) - 0.000141 * std::cos(m * 2.0);
double3 ecliptic;
ecliptic.x = distance * std::cos(longitude) * std::cos(latitude);
ecliptic.y = distance * std::sin(longitude) * std::cos(latitude);
ecliptic.z = distance * std::sin(latitude);
return ecliptic;
}
double3 approx_moon_ecliptic(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double l1 = 3.8104 + 8399.7091 * t;
const double m1 = 2.3554 + 8328.6911 * t;
const double m = 6.2300 + 628.3019 * t;
const double d = 5.1985 + 7771.3772 * t;
const double d2 = d * 2.0;
const double f = 1.6280 + 8433.4663 * t;
const double longitude = l1
+ 0.1098 * std::sin(m1)
+ 0.0222 * std::sin(d2 - m1)
+ 0.0115 * std::sin(d2)
+ 0.0037 * std::sin(m1 * 2.0)
- 0.0032 * std::sin(m)
- 0.0020 * std::sin(d2)
+ 0.0010 * std::sin(d2 - m1 * 2.0)
+ 0.0010 * std::sin(d2 - m - m1)
+ 0.0009 * std::sin(d2 + m1)
+ 0.0008 * std::sin(d2 - m)
+ 0.0007 * std::sin(m1 - m)
- 0.0006 * std::sin(d)
- 0.0005 * std::sin(m + m1);
const double latitude = 0.0895 * sin(f)
+ 0.0049 * std::sin(m1 + f)
+ 0.0048 * std::sin(m1 - f)
+ 0.0030 * std::sin(d2 - f)
+ 0.0010 * std::sin(d2 + f - m1)
+ 0.0008 * std::sin(d2 - f - m1)
+ 0.0006 * std::sin(d2 + f);
const double r = 1.0 / (0.016593
+ 0.000904 * std::cos(m1)
+ 0.000166 * std::cos(d2 - m1)
+ 0.000137 * std::cos(d2)
+ 0.000049 * std::cos(m1 * 2.0)
+ 0.000015 * std::cos(d2 + m1)
+ 0.000009 * std::cos(d2 - m));
double3 ecliptic;
ecliptic.x = r * std::cos(longitude) * std::cos(latitude);
ecliptic.y = r * std::sin(longitude) * std::cos(latitude);
ecliptic.z = r * std::sin(latitude);
return ecliptic;
}
double3x3 approx_moon_ecliptic_rotation(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double l1 = 3.8104 + 8399.7091 * t;
const double f = 1.6280 + 8433.4663 * t;
const double az0 = f + math::pi<double>;
const double ax = 0.026920;
const double az1 = l1 - f;
double3x3 rz0 =
{
cos(az0), -sin(az0), 0,
sin(az0), cos(az0), 0,
0, 0, 1
};
double3x3 rx =
{
1, 0, 0,
0, cos(ax), -sin(ax),
0, sin(ax), cos(ax)
};
double3x3 rz1 =
{
cos(az1), -sin(az1), 0,
sin(az1), cos(az1), 0,
0, 0, 1
};
return rz0 * rx * rz1;
}
} // namespace ast

+ 32
- 0
src/game/astronomy/celestial-mechanics.hpp View File

@ -25,6 +25,38 @@
namespace ast
{
/**
* Approximates the obliquity of the ecliptic.
*
* @param jd Julian date.
* @return Obliquity of the ecliptic, in radians.
*/
double approx_ecliptic_obliquity(double jd);
/**
* Approximates the ecliptic coordinates of the Earth's sun.
*
* @param jd Julian date.
* @return Ecliptic rectangular geocentric coordinates of the Earth's sun, with distance in AU.
*/
double3 approx_sun_ecliptic(double jd);
/**
* Approximates the ecliptic coordinates of the Earth's moon.
*
* @param jd Julian date.
* @return Ecliptic rectangular geocentric coordinates of the Earth's moon, with distance in Earth radii.
*/
double3 approx_moon_ecliptic(double jd);
/**
* Approximates the ecliptic rotation of the Earth's moon.
*
* @param jd Julian date.
* @return Rotation matrix representing the moon's rotation in ecliptic space.
*/
double3x3 approx_moon_ecliptic_rotation(double jd);
struct orbital_elements
{
double a; ///< Semi-major axis (km)

+ 62
- 0
src/game/astronomy/celestial-time.cpp View File

@ -0,0 +1,62 @@
/*
* Copyright (C) 2020 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 "celestial-time.hpp"
#include "math/angles.hpp"
#include <cmath>
namespace ast
{
double ut_to_jd(int year, int month, int day, int hour, int minute, double second)
{
if (month < 3)
{
month += 12;
year -= 1;
}
const signed long Y = year;
const signed long M = month;
const signed long D = day;
const signed long JDN = (1461*(Y+4800+(M-14)/12))/4+(367*(M-2-12*((M-14)/12)))/12-(3*((Y+4900+(M-14)/12)/100))/4+D-32075;
const double h = static_cast<double>(hour - 12) / 24.0;
const double m = static_cast<double>(minute) / 1440.0;
const double s = second / 86400.0;
return static_cast<double>(JDN) + h + m + s;
}
double jd_to_gmst(double jd)
{
return math::wrap_radians<double>(4.894961212 + 6.300388098 * (jd - 2451545.0));
}
double jd_to_lmst(double jd, double longitude)
{
return gmst_to_lmst(jd_to_gmst(jd), longitude);
}
double gmst_to_lmst(double gmst, double longitude)
{
return gmst + longitude;
}
} // namespace ast

+ 66
- 0
src/game/astronomy/celestial-time.hpp View File

@ -0,0 +1,66 @@
/*
* Copyright (C) 2020 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/>.
*/
#ifndef ANTKEEPER_CELESTIAL_TIME_HPP
#define ANTKEEPER_CELESTIAL_TIME_HPP
namespace ast
{
/**
* Calculates the Julian date from a universal time.
*
* @param year Gregorian year, with 1 BC as 0.
* @param month Gregorian month, on [1, 12].
* @param day Gregorian day, on [1, 31].
* @param hour Hour, on [0, 23].
* @param minute Minute, on [0, 59].
* @param second Second on [0, 60).
* @return Julian date with fractional day.
*/
double ut_to_jd(int year, int month, int day, int hour, int minute, double second);
/**
* Calculates the Greenwich mean sidereal time (GMST) from a Julian date.
*
* @param jd Julian date.
* @return GMST, in radians.
*/
double jd_to_gmst(double jd);
/**
* Calculates local mean sidereal time (LMST) from a Julian date.
*
* @param jd Julian date.
* @param longitude Longitude of the observer, in radians.
*/
double jd_to_lmst(double jd, double longitude);
/**
* Calculates local mean sidereal time (LMST) from Greenwich mean sidereal time (GMST).
*
* @param gmst Greenwich mean sidereal time, in radians.
* @param longitude Longitude of the observer, in radians.
* @return Local mean sidereal time, in radians.
*/
double gmst_to_lmst(double gmst, double longitude);
} // namespace ast
#endif // ANTKEEPER_CELESTIAL_TIME_HPP

+ 9
- 9
src/game/states/play-state.cpp View File

@ -81,7 +81,7 @@ void play_state_enter(game_context* ctx)
sky_pass->set_moon_model(ctx->resource_manager->load<model>("moon.mdl"));
ctx->weather_system->set_location(ctx->biome->location[0], ctx->biome->location[1], ctx->biome->location[2]);
ctx->weather_system->set_time(2017, 8, 21, 5, 0, 0, -7.0);
ctx->weather_system->set_time(2017, 8, 21, 5, 0, 0.0, -7.0);
ctx->weather_system->set_sky_palette(ctx->biome->sky_palette);
ctx->weather_system->set_sun_palette(ctx->biome->sun_palette);
ctx->weather_system->set_ambient_palette(ctx->biome->ambient_palette);
@ -118,7 +118,7 @@ void play_state_enter(game_context* ctx)
marker_archetype->assign(ecs_registry, ctx->marker_entity);
container_archetype->assign(ecs_registry, ctx->container_entity);
twig_archetype->assign(ecs_registry, ctx->twig_entity);
// Create flashlight and light cone, set light cone parent to flashlight, and move both to underworld scene
flashlight_archetype->assign(ecs_registry, ctx->flashlight_entity);
auto flashlight_light_cone = flashlight_light_cone_archetype->create(ecs_registry);
@ -137,7 +137,7 @@ void play_state_enter(game_context* ctx)
//ec::bind_transform(ecs_registry, lens_light_cone, ctx->lens_entity);
ec::parent(ecs_registry, lens_light_cone, ctx->lens_entity);
// Hide inactive tools
ec::assign_render_layers(ecs_registry, ctx->forceps_entity, 0);
@ -241,19 +241,19 @@ void play_state_enter(game_context* ctx)
ecs_registry.assign_or_replace<ecs::transform_component>(ctx->focal_point_entity, focal_point_transform);
ecs_registry.assign_or_replace<ecs::camera_follow_component>(ctx->focal_point_entity, focal_point_follow);
ecs_registry.assign_or_replace<ecs::snap_component>(ctx->focal_point_entity, focal_point_snap);
// Setup camera
ctx->overworld_camera->look_at({0, 0, 1}, {0, 0, 0}, {0, 1, 0});
ctx->camera_system->set_camera(ctx->overworld_camera);
auto ant_head = ant_head_archetype->create(ecs_registry);
ec::place(ecs_registry, ant_head, {50, 0});
ctx->overworld_scene->update_tweens();
// Allocate a nest
nest* nest = new ::nest();
// Setup initial nest parameters
float tunnel_radius = 1.15f;
nest->set_tunnel_radius(tunnel_radius);
@ -275,7 +275,7 @@ void play_state_enter(game_context* ctx)
chamber.outer_radius = 10.0f;
central_shaft->chambers.push_back(chamber);
}
// Dig nest shafts
float shift = 0.1f;
for (int i = 0; i < 800; ++i)

+ 16
- 206
src/game/systems/weather-system.cpp View File

@ -26,6 +26,8 @@
#include "utility/gamma.hpp"
#include "resources/image.hpp"
#include "game/astronomy/celestial-coordinates.hpp"
#include "game/astronomy/celestial-mechanics.hpp"
#include "game/astronomy/celestial-time.hpp"
#include <cmath>
#include <iostream>
@ -33,190 +35,6 @@ static constexpr double hours_per_day = 24.0;
static constexpr double minutes_per_day = hours_per_day * 60.0;
static constexpr double seconds_per_day = minutes_per_day * 60.0;
/**
*
* @param year Gregorian year
* @param month Month (1 = January, 12 = December)
* @param day Day (1-31)
* @param time Universal time in decimal hours.
*/
static double julian_day(int year, int month, int day, double time)
{
if (month < 3)
{
month += 12;
year -= 1;
}
double y = static_cast<double>(year);
double m = static_cast<double>(month);
double d = static_cast<double>(day);
return std::floor(365.25 * y) + std::floor(30.6001 * (m + 1.0)) - 15.0 + 1720996.5 + d + time;
}
/**
* Calculates the ecliptic rectangular geocentric coordinates of the sun, with distance in AU.
*/
double3 calculate_sun_ecliptic(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double m = 6.24 + 628.302 * t;
const double longitude = 4.895048 + 628.331951 * t + (0.033417 - 0.000084 * t) * std::sin(m) + 0.000351 * std::sin(m * 2.0);
const double latitude = 0.0;
const double distance = 1.000140 - (0.016708 - 0.000042 * t) * std::cos(m) - 0.000141 * std::cos(m * 2.0);
double3 ecliptic;
ecliptic.x = distance * std::cos(longitude) * std::cos(latitude);
ecliptic.y = distance * std::sin(longitude) * std::cos(latitude);
ecliptic.z = distance * std::sin(latitude);
return ecliptic;
}
/**
* Calculates the ecliptic rectangular geocentric coordinates of the moon, with distance in Earth radii.
*/
double3 calculate_moon_ecliptic(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double l1 = 3.8104 + 8399.7091 * t;
const double m1 = 2.3554 + 8328.6911 * t;
const double m = 6.2300 + 628.3019 * t;
const double d = 5.1985 + 7771.3772 * t;
const double d2 = d * 2.0;
const double f = 1.6280 + 8433.4663 * t;
const double longitude = l1
+ 0.1098 * std::sin(m1)
+ 0.0222 * std::sin(d2 - m1)
+ 0.0115 * std::sin(d2)
+ 0.0037 * std::sin(m1 * 2.0)
- 0.0032 * std::sin(m)
- 0.0020 * std::sin(d2)
+ 0.0010 * std::sin(d2 - m1 * 2.0)
+ 0.0010 * std::sin(d2 - m - m1)
+ 0.0009 * std::sin(d2 + m1)
+ 0.0008 * std::sin(d2 - m)
+ 0.0007 * std::sin(m1 - m)
- 0.0006 * std::sin(d)
- 0.0005 * std::sin(m + m1);
const double latitude = 0.0895 * sin(f)
+ 0.0049 * std::sin(m1 + f)
+ 0.0048 * std::sin(m1 - f)
+ 0.0030 * std::sin(d2 - f)
+ 0.0010 * std::sin(d2 + f - m1)
+ 0.0008 * std::sin(d2 - f - m1)
+ 0.0006 * std::sin(d2 + f);
const double r = 1.0 / (0.016593
+ 0.000904 * std::cos(m1)
+ 0.000166 * std::cos(d2 - m1)
+ 0.000137 * std::cos(d2)
+ 0.000049 * std::cos(m1 * 2.0)
+ 0.000015 * std::cos(d2 + m1)
+ 0.000009 * std::cos(d2 - m));
double3 ecliptic;
ecliptic.x = r * std::cos(longitude) * std::cos(latitude);
ecliptic.y = r * std::sin(longitude) * std::cos(latitude);
ecliptic.z = r * std::sin(latitude);
return ecliptic;
}
double3x3 find_moon_ecliptic_rotation(double jd)
{
const double t = (jd - 2451545.0) / 36525.0;
const double l1 = 3.8104 + 8399.7091 * t;
const double f = 1.6280 + 8433.4663 * t;
const double az0 = f + math::pi<double>;
const double ax = 0.026920;
const double az1 = l1 - f;
double3x3 rz0 =
{
cos(az0), -sin(az0), 0,
sin(az0), cos(az0), 0,
0, 0, 1
};
double3x3 rx =
{
1, 0, 0,
0, cos(ax), -sin(ax),
0, sin(ax), cos(ax)
};
double3x3 rz1 =
{
cos(az1), -sin(az1), 0,
sin(az1), cos(az1), 0,
0, 0, 1
};
return rz0 * rx * rz1;
}
/// @see http://www.stjarnhimlen.se/comp/ppcomp.html
/// @see http://www.geoastro.de/elevazmoon/basics/index.htm
void ecliptic_to_equatorial(double longitude, double latitude, double ecl, double* right_ascension, double* declination)
{
double eclip_x = std::cos(longitude) * std::cos(latitude);
double eclip_y = std::sin(longitude) * std::cos(latitude);
double eclip_z = std::sin(latitude);
double equat_x = eclip_x;
double equat_y = eclip_y * std::cos(ecl) - eclip_z * std::sin(ecl);
double equat_z = eclip_y * std::sin(ecl) + eclip_z * std::cos(ecl);
*right_ascension = std::atan2(equat_y, equat_x);
*declination = std::atan2(equat_z, sqrt(equat_x * equat_x + equat_y * equat_y));
}
/// @see http://www.stjarnhimlen.se/comp/ppcomp.html
/// @see http://www.geoastro.de/elevazmoon/basics/index.htm
void equatorial_to_horizontal(double right_ascension, double declination, double lmst, double latitude, double* azimuth, double* elevation)
{
double hour_angle = lmst - right_ascension;
double x = std::cos(hour_angle) * std::cos(declination);
double y = std::sin(hour_angle) * std::cos(declination);
double z = std::sin(declination);
double horiz_x = x * std::cos(math::half_pi<double> - latitude) - z * std::sin(math::half_pi<double> - latitude);
double horiz_y = y;
double horiz_z = x * std::sin(math::half_pi<double> - latitude) + z * std::cos(math::half_pi<double> - latitude);
*azimuth = math::wrap_radians<double>(std::atan2(horiz_y, horiz_x) + math::pi<double>);
*elevation = math::wrap_radians<double>(std::atan2(horiz_z, std::sqrt(horiz_x * horiz_x + horiz_y * horiz_y)));
}
double3x3 horizontal_to_right_handed()
{
return double3x3
{
0.0, 0.0, 1.0,
1.0, 0.0, 0.0,
0.0, -1.0, 0.0
};
}
/**
* Calculates the Greenwich mean sidereal time (GMST) from a Julian day.
*
* @param jd Julian day.
* @return GMST, in radians.
*/
static double jd_to_gmst(double jd)
{
return math::wrap_radians<double>(4.894961212 + 6.300388098 * (jd - 2451545.0));
}
weather_system::weather_system(entt::registry& registry):
entity_system(registry),
ambient_light(nullptr),
@ -239,42 +57,38 @@ void weather_system::update(double t, double dt)
const float latitude = location[0];
const float longitude = location[1];
// Calculate local mean sidereal time (LMST)
// Calculate local time
double time_correction = longitude / (math::two_pi<double> / 24.0);
double local_jd = jd + time_correction / 24.0 - 0.5;
double local_time = (local_jd - std::floor(local_jd)) * 24.0;
double hour = local_time;
double gmst = jd_to_gmst(jd);
double lmst = gmst + longitude;
// Obliquity of the ecliptic
double ecl = math::radians<double>(23.4393 - 3.563e-7 * (jd - 2451545.0));
// Solar distance in AU
//double sr = ...
// Apparent radius in degrees
//double sradius = 0.2666 / sr;
double lmst = ast::jd_to_lmst(jd, longitude);
double ecl = ast::approx_ecliptic_obliquity(jd);
double3x3 ecliptic_to_horizontal = ast::ecliptic_to_horizontal(ecl, latitude, lmst);
double3 sun_ecliptic = calculate_sun_ecliptic(jd);
double3 sun_ecliptic = ast::approx_sun_ecliptic(jd);
double3 sun_horizontal = ecliptic_to_horizontal * sun_ecliptic;
sun_horizontal.z -= 4.25875e-5; // Subtract one earth radius (in AU), for positon of observer
double3 sun_spherical = ast::rectangular_to_spherical(sun_horizontal);
double3 sun_positiond = horizontal_to_right_handed() * sun_horizontal;
double3 sun_positiond = ast::horizontal_to_right_handed * sun_horizontal;
float2 sun_az_el = {static_cast<float>(sun_spherical.z) - math::pi<float>, static_cast<float>(sun_spherical.y)};
float3 sun_position = math::normalize(float3{static_cast<float>(sun_positiond.x), static_cast<float>(sun_positiond.y), static_cast<float>(sun_positiond.z)});
double3 moon_ecliptic = calculate_moon_ecliptic(jd);
double3 moon_ecliptic = ast::approx_moon_ecliptic(jd);
double3 moon_horizontal = ecliptic_to_horizontal * moon_ecliptic;
moon_horizontal.z -= 1.0; // Subtract one earth radius, for position of observer
double3 moon_spherical = ast::rectangular_to_spherical(moon_horizontal);
double3 moon_positiond = horizontal_to_right_handed() * moon_horizontal;
double3 moon_positiond = ast::horizontal_to_right_handed * moon_horizontal;
float2 moon_az_el = {static_cast<float>(moon_spherical.z) - math::pi<float>, static_cast<float>(moon_spherical.y)};
float3 moon_position = math::normalize(float3{static_cast<float>(moon_positiond.x), static_cast<float>(moon_positiond.y), static_cast<float>(moon_positiond.z)});
//std::cout << "new moon: " << math::degrees(moon_az_el[0]) << ", " << math::degrees(moon_az_el[1]) << std::endl;
double3x3 moon_rotation_matrix = horizontal_to_right_handed() * ecliptic_to_horizontal;
double3x3 moon_rotation_matrix = ast::horizontal_to_right_handed * ecliptic_to_horizontal;
math::quaternion<double> moon_rotationd = math::normalize(math::quaternion_cast(moon_rotation_matrix) * math::angle_axis(math::half_pi<double>, double3{0, 1, 0}) * math::angle_axis(-math::half_pi<double>, double3{0, 0, -1}));
math::quaternion<float> moon_rotation =
{
@ -300,9 +114,6 @@ void weather_system::update(double t, double dt)
moon_light->set_rotation(moon_az_el_rotation);
}
std::size_t hour_index = static_cast<std::size_t>(hour);
float lerp_factor = hour - std::floor(hour);
float sun_gradient_position = static_cast<float>(std::max<double>(0.0, ((sun_az_el[1] + math::half_pi<double>) / math::pi<double>)));
float moon_gradient_position = static_cast<float>(std::max<double>(0.0, ((moon_az_el[1] + math::half_pi<double>) / math::pi<double>)));
float sky_gradient_position = sun_gradient_position;
@ -325,7 +136,7 @@ void weather_system::update(double t, double dt)
sky_pass->set_horizon_color(horizon_color);
sky_pass->set_zenith_color(zenith_color);
sky_pass->set_time_of_day(static_cast<float>(hour * 60.0 * 60.0));
sky_pass->set_time_of_day(static_cast<float>(local_time * 60.0 * 60.0));
sky_pass->set_observer_location(location[0], location[1], location[2]);
sky_pass->set_sun_coordinates(sun_position, sun_az_el);
sky_pass->set_moon_coordinates(moon_position, moon_az_el);
@ -399,10 +210,9 @@ void weather_system::set_material_pass(::material_pass* pass)
material_pass = pass;
}
void weather_system::set_time(int year, int month, int day, int hour, int minute, int second, double tc)
void weather_system::set_time(int year, int month, int day, int hour, int minute, double second, double tc)
{
double time = ((static_cast<double>(hour) - tc) + ((static_cast<double>(minute) + static_cast<double>(second) / 60.0) / 60.0)) / 24.0;
jd = julian_day(year, month, day, time);
jd = ast::ut_to_jd(year, month, day, hour, minute, second) - tc / 24.0;
}
void weather_system::set_time_scale(float scale)

+ 1
- 1
src/game/systems/weather-system.hpp View File

@ -53,7 +53,7 @@ public:
void set_material_pass(::material_pass* pass);
/// @param tc Timezone correction, in hours
void set_time(int year, int month, int day, int hour, int minute, int second, double tc);
void set_time(int year, int month, int day, int hour, int minute, double second, double tc);
void set_time_scale(float scale);
void set_sky_palette(const ::image* image);

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