Optimize ephemeris position calculations, calculate starlight illuminance from catalog

src/entity/systems/astronomy.cpp

@@ -66,7 +66,8 @@ astronomy::astronomy(entity::registry& registry):
 	moon_light(nullptr),
 	camera(nullptr),
 	sky_pass(nullptr),
-	exposure_offset(0.0)
+	exposure_offset(0.0),
+	starlight_illuminance(0.0)
 {
 	// Construct transformation which transforms coordinates from ENU to EUS
 	enu_to_eus = math::transformation::se3<double>
@@ -79,6 +80,12 @@ astronomy::astronomy(entity::registry& registry):
 	registry.on_replace<entity::component::celestial_body>().connect<&astronomy::on_celestial_body_replace>(this);
 }
 
+astronomy::~astronomy()
+{
+	registry.on_construct<entity::component::celestial_body>().disconnect<&astronomy::on_celestial_body_construct>(this);
+	registry.on_replace<entity::component::celestial_body>().disconnect<&astronomy::on_celestial_body_replace>(this);
+}
+
 void astronomy::update(double t, double dt)
 {
 	double total_illuminance = 0.0;
@@ -271,7 +278,6 @@ void astronomy::update(double t, double dt)
 			sky_light_illuminance += sky_illuminance;
 			
 			// Add starlight illuminance to sky light illuminance
-			const double starlight_illuminance = 0.0002;
 			sky_light_illuminance += starlight_illuminance;
 			
 			// Add sky light illuminance to total illuminance
@@ -478,6 +484,11 @@ void astronomy::set_exposure_offset(float offset)
 	exposure_offset = offset;
 }
 
+void astronomy::set_starlight_illuminance(double illuminance)
+{
+	starlight_illuminance = illuminance;
+}
+
 void astronomy::set_sky_pass(::render::sky_pass* pass)
 {
 	this->sky_pass = pass;

src/entity/systems/astronomy.hpp

@@ -43,6 +43,7 @@ class astronomy:
 {
 public:
 	astronomy(entity::registry& registry);
+	~astronomy();
 	
 	/**
 	 * Scales then adds the timestep `dt` to the current time, then recalculates the positions of celestial bodies.
@@ -86,6 +87,8 @@ public:
 	void set_camera(scene::camera* camera);
 	void set_exposure_offset(float offset);
 	
+	void set_starlight_illuminance(double illuminance);
+	
 	inline float get_exposure_offset() const { return exposure_offset; };
 	
 	void set_sky_pass(::render::sky_pass* pass);
@@ -115,6 +118,7 @@ private:
 	scene::camera* camera;
 	::render::sky_pass* sky_pass;
 	float exposure_offset;
+	double starlight_illuminance;
 };
 
 } // namespace system

src/entity/systems/orbit.cpp

@@ -29,7 +29,16 @@ orbit::orbit(entity::registry& registry):
 	ephemeris(nullptr),
 	time(0.0),
 	time_scale(1.0)
-{}
+{
+	registry.on_construct<entity::component::orbit>().connect<&orbit::on_orbit_construct>(this);
+	registry.on_replace<entity::component::orbit>().connect<&orbit::on_orbit_replace>(this);
+}
+
+orbit::~orbit()
+{
+	registry.on_construct<entity::component::orbit>().disconnect<&orbit::on_orbit_construct>(this);
+	registry.on_replace<entity::component::orbit>().disconnect<&orbit::on_orbit_replace>(this);
+}
 
 void orbit::update(double t, double dt)
 {
@@ -40,7 +49,7 @@ void orbit::update(double t, double dt)
 		return;
 	
 	// Calculate positions of ephemeris items, in meters
-	for (std::size_t i = 0; i < ephemeris->size(); ++i)
+	for (int i: ephemeris_indices)
 		positions[i] = (*ephemeris)[i].position(time) * 1000.0;
 	
 	// Propagate orbits
@@ -75,5 +84,15 @@ void orbit::set_time_scale(double scale)
 	time_scale = scale;
 }
 
+void orbit::on_orbit_construct(entity::registry& registry, entity::id entity_id, entity::component::orbit& component)
+{
+	ephemeris_indices.insert(component.ephemeris_index);
+}
+
+void orbit::on_orbit_replace(entity::registry& registry, entity::id entity_id, entity::component::orbit& component)
+{
+	ephemeris_indices.insert(component.ephemeris_index);
+}
+
 } // namespace system
 } // namespace entity

src/entity/systems/orbit.hpp

@@ -25,6 +25,7 @@
 #include "entity/id.hpp"
 #include "entity/components/orbit.hpp"
 #include "physics/orbit/ephemeris.hpp"
+#include <unordered_set>
 
 namespace entity {
 namespace system {
@@ -37,6 +38,7 @@ class orbit:
 {
 public:
 	orbit(entity::registry& registry);
+	~orbit();
 	
 	/**
 	 * Scales then adds the timestep `dt` to the current time, then recalculates the positions of orbiting bodies.
@@ -68,10 +70,14 @@ public:
 	void set_ephemeris(const physics::orbit::ephemeris<double>* ephemeris);
 	
 private:
+	void on_orbit_construct(entity::registry& registry, entity::id entity_id, entity::component::orbit& component);
+	void on_orbit_replace(entity::registry& registry, entity::id entity_id, entity::component::orbit& component);
+	
 	const physics::orbit::ephemeris<double>* ephemeris;
 	double time;
 	double time_scale;
 	std::vector<double3> positions;
+	std::unordered_set<int> ephemeris_indices;
 };
 
 } // namespace system

src/game/world.cpp

@@ -75,6 +75,7 @@ void create_stars(game::context& ctx)
 	float* star_vertex_data = new float[star_count * star_vertex_size];
 	float* star_vertex = star_vertex_data;
 	
+	// Init starlight illuminance
 	double starlight_illuminance = 0.0;
 	
 	// Build star catalog vertex data
@@ -100,8 +101,6 @@ void create_stars(game::context& ctx)
 			continue;
 		}
 		
-		starlight_illuminance += physics::light::vmag::to_illuminance(vmag);
-		
 		// Convert right ascension and declination from degrees to radians
 		ra = math::wrap_radians(math::radians(ra));
 		dec = math::wrap_radians(math::radians(dec));
@@ -109,6 +108,9 @@ void create_stars(game::context& ctx)
 		// Convert ICRF coordinates from spherical to Cartesian
 		double3 position = physics::orbit::frame::bci::cartesian(double3{1.0, dec, ra});
 		
+		// Convert apparent magnitude to brightness factor relative to a 0th magnitude star
+		double brightness = physics::light::vmag::to_brightness(vmag);
+		
 		// Convert color index to color temperature
 		double cct = color::index::bv_to_cct(bv_color);
 		
@@ -118,24 +120,22 @@ void create_stars(game::context& ctx)
 		// Transform XYZ color to ACEScg colorspace
 		double3 color_acescg = color::xyz::to_acescg(color_xyz);
 		
-		// Convert apparent magnitude to brightness factor relative to a 0th magnitude star
-		double brightness = physics::light::vmag::to_brightness(vmag);
-		
 		// Scale color by relative brightness
-		double3 scaled_color = color_acescg * brightness;
+		color_acescg *= brightness;
 		
 		// Build vertex
 		*(star_vertex++) = static_cast<float>(position.x);
 		*(star_vertex++) = static_cast<float>(position.y);
 		*(star_vertex++) = static_cast<float>(position.z);
-		*(star_vertex++) = static_cast<float>(scaled_color.x);
-		*(star_vertex++) = static_cast<float>(scaled_color.y);
-		*(star_vertex++) = static_cast<float>(scaled_color.z);
+		*(star_vertex++) = static_cast<float>(color_acescg.x);
+		*(star_vertex++) = static_cast<float>(color_acescg.y);
+		*(star_vertex++) = static_cast<float>(color_acescg.z);
 		*(star_vertex++) = static_cast<float>(brightness);
+		
+		// Convert apparent magnitude to illuminance and add to total starlight
+		starlight_illuminance += physics::light::vmag::to_illuminance(vmag);
 	}
 	
-	std::cout << "TOTAL STARLIGHT: " << starlight_illuminance << std::endl;
-	
 	// Unload star catalog
 	ctx.resource_manager->unload("stars.csv");
 	
@@ -188,6 +188,9 @@ void create_stars(game::context& ctx)
 	
 	// Pass stars model to sky pass
 	ctx.sky_pass->set_stars_model(stars_model);
+	
+	// Pass starlight illuminance to astronomy system
+	ctx.astronomy_system->set_starlight_illuminance(starlight_illuminance);
 }
 
 void create_sun(game::context& ctx)