source/src/game/states/loading.cpp

/*
 * Copyright (C) 2021  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 "game/states/loading.hpp"
#include "application.hpp"
#include "astro/illuminance.hpp"
#include "color/color.hpp"
#include "entity/components/atmosphere.hpp"
#include "entity/components/blackbody.hpp"
#include "entity/components/celestial-body.hpp"
#include "entity/components/orbit.hpp"
#include "entity/components/terrain.hpp"
#include "entity/components/transform.hpp"
#include "entity/systems/astronomy.hpp"
#include "entity/systems/orbit.hpp"
#include "entity/commands.hpp"
#include "game/states/nuptial-flight.hpp"
#include "game/states/splash.hpp"
#include "game/states/forage.hpp"
#include "geom/spherical.hpp"
#include "gl/drawing-mode.hpp"
#include "gl/vertex-array.hpp"
#include "gl/vertex-attribute-type.hpp"
#include "gl/vertex-buffer.hpp"
#include "physics/light/photometry.hpp"
#include "physics/orbit/orbit.hpp"
#include "renderer/material.hpp"
#include "renderer/model.hpp"
#include "renderer/passes/shadow-map-pass.hpp"
#include "renderer/vertex-attributes.hpp"
#include "resources/resource-manager.hpp"
#include "scene/ambient-light.hpp"
#include "scene/directional-light.hpp"
#include "utility/timestamp.hpp"

namespace game {
namespace state {
namespace loading {

/// Creates or loads control configuration
static void load_controls(game::context* ctx);

static input::gamepad_response_curve parse_response_curve(const std::string& curve);

/// Creates the universe and solar system.
static void cosmogenesis(game::context* ctx);

/// Creates a sun.
static void heliogenesis(game::context* ctx);

/// Creates a planet.
static void planetogenesis(game::context* ctx);

/// Creates a moon.
static void selenogenesis(game::context* ctx);

/// Creates fixed stars.
static void extrasolar_heliogenesis(game::context* ctx);

/// Creates an ant colony
static void colonigenesis(game::context* ctx);

void enter(game::context* ctx)
{
	// Load controls
	ctx->logger->push_task("Loading controls");
	try
	{
		load_controls(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Create universe
	ctx->logger->push_task("Creating the universe");
	try
	{
		cosmogenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Determine next game state
	application::state next_state;
	if (ctx->option_quick_start.has_value())
	{
		next_state.name = "forage";
		next_state.enter = std::bind(game::state::forage::enter, ctx);
		next_state.exit = std::bind(game::state::forage::exit, ctx);
	}
	else
	{
		next_state.name = "splash";
		next_state.enter = std::bind(game::state::splash::enter, ctx);
		next_state.exit = std::bind(game::state::splash::exit, ctx);
	}
	
	// Queue next game state
	ctx->app->queue_state(next_state);
}

void exit(game::context* ctx)
{}

void load_controls(game::context* ctx)
{
	// Allocate known controls
	ctx->controls["toggle_fullscreen"] = new input::control();
	ctx->controls["screenshot"] = new input::control();
	ctx->controls["menu_up"] = new input::control();
	ctx->controls["menu_down"] = new input::control();
	ctx->controls["menu_left"] = new input::control();
	ctx->controls["menu_right"] = new input::control();
	ctx->controls["menu_select"] = new input::control();
	ctx->controls["menu_back"] = new input::control();
	ctx->controls["dolly_forward"] = new input::control();
	ctx->controls["dolly_backward"] = new input::control();
	ctx->controls["truck_left"] = new input::control();
	ctx->controls["truck_right"] = new input::control();
	ctx->controls["pedestal_up"] = new input::control();
	ctx->controls["pedestal_down"] = new input::control();
	ctx->controls["move_slow"] = new input::control();
	ctx->controls["move_fast"] = new input::control();
	ctx->controls["mouse_rotate"] = new input::control();
	ctx->controls["pan_left_gamepad"] = new input::control();
	ctx->controls["pan_left_mouse"] = new input::control();
	ctx->controls["pan_right_gamepad"] = new input::control();
	ctx->controls["pan_right_mouse"] = new input::control();
	ctx->controls["tilt_up_gamepad"] = new input::control();
	ctx->controls["tilt_up_mouse"] = new input::control();
	ctx->controls["tilt_down_gamepad"] = new input::control();
	ctx->controls["tilt_down_mouse"] = new input::control();
	ctx->controls["use_tool"] = new input::control();
	
	// Set activation threshold for menu navigation controls to mitigate drifting gamepad axes
	const float menu_activation_threshold = 0.1f;
	ctx->controls["menu_up"]->set_activation_threshold(menu_activation_threshold);
	ctx->controls["menu_down"]->set_activation_threshold(menu_activation_threshold);
	ctx->controls["menu_left"]->set_activation_threshold(menu_activation_threshold);
	ctx->controls["menu_right"]->set_activation_threshold(menu_activation_threshold);
	
	// Get keyboard and mouse devices
	input::keyboard* keyboard = ctx->app->get_keyboard();
	input::mouse* mouse = ctx->app->get_mouse();
	
	const std::unordered_map<std::string, input::gamepad_button> gamepad_button_map =
	{
		{"a", input::gamepad_button::a},
		{"b", input::gamepad_button::b},
		{"x", input::gamepad_button::x},
		{"y", input::gamepad_button::y},
		{"back", input::gamepad_button::back},
		{"guide", input::gamepad_button::guide},
		{"start", input::gamepad_button::start},
		{"leftstick", input::gamepad_button::left_stick},
		{"rightstick", input::gamepad_button::right_stick},
		{"leftshoulder", input::gamepad_button::left_shoulder},
		{"rightshoulder", input::gamepad_button::right_shoulder},
		{"dpup", input::gamepad_button::dpad_up},
		{"dpdown", input::gamepad_button::dpad_down},
		{"dpleft", input::gamepad_button::dpad_left},
		{"dpright", input::gamepad_button::dpad_right}
	};
	
	const std::unordered_map<std::string, input::gamepad_axis> gamepad_axis_map =
	{
		{"leftx", input::gamepad_axis::left_x},
		{"lefty", input::gamepad_axis::left_y},
		{"rightx", input::gamepad_axis::right_x},
		{"righty", input::gamepad_axis::right_y},
		{"lefttrigger", input::gamepad_axis::left_trigger},
		{"righttrigger", input::gamepad_axis::right_trigger}
	};
	
	// Check if a control profile is set in the config file
	if (ctx->config->contains("control_profile"))
	{
		// Load control profile
		json* profile = ctx->resource_manager->load<json>((*ctx->config)["control_profile"].get<std::string>());
		
		// Parse control profile
		for (auto it = profile->begin(); it != profile->end(); ++it)
		{
			// Parse control name
			if (!it->contains("name"))
			{
				ctx->logger->warning("Unnamed control in control profile");
				continue;
			}
			std::string name = (*it)["name"].get<std::string>();
			
			// Find or create control
			input::control* control;
			if (ctx->controls.count(name))
			{
				control = ctx->controls[name];
			}
			else
			{
				control = new input::control;
				ctx->controls[name] = control;
			}
			
			// Parse control device
			if (!it->contains("device"))
			{
				ctx->logger->warning("Control \"" + name + "\" not mapped to a device");
				continue;
			}
			std::string device = (*it)["device"].get<std::string>();
			
			if (device == "keyboard")
			{
				// Parse key name
				if (!it->contains("key"))
				{
					ctx->logger->warning("Control \"" + name + "\" has invalid keyboard mapping");
					continue;
				}
				std::string key = (*it)["key"].get<std::string>();
				
				// Get scancode from key name
				input::scancode scancode = keyboard->get_scancode_from_name(key.c_str());
				if (scancode == input::scancode::unknown)
				{
					ctx->logger->warning("Control \"" + name + "\" mapped to unknown keyboard key \"" + key + "\"");
					continue;
				}
				
				// Map control to keyboard key
				ctx->input_event_router->add_mapping(input::key_mapping(control, nullptr, scancode));
				
				ctx->logger->log("Mapped control \"" + name + "\" to keyboard key \"" + key + "\"");
			}
			else if (device == "mouse")
			{
				if (it->contains("button"))
				{
					// Parse mouse button index
					int button = (*it)["button"].get<int>();
					
					// Map control to mouse button
					ctx->input_event_router->add_mapping(input::mouse_button_mapping(control, nullptr, button));
					
					ctx->logger->log("Mapped control \"" + name + "\" to mouse button " + std::to_string(button));
				}
				else if (it->contains("wheel"))
				{
					// Parse mouse wheel axis
					std::string wheel = (*it)["wheel"].get<std::string>();
					input::mouse_wheel_axis axis;
					if (wheel == "x+")
						axis = input::mouse_wheel_axis::positive_x;
					else if (wheel == "x-")
						axis = input::mouse_wheel_axis::negative_x;
					else if (wheel == "y+")
						axis = input::mouse_wheel_axis::positive_y;
					else if (wheel == "y-")
						axis = input::mouse_wheel_axis::negative_y;
					else
					{
						ctx->logger->warning("Control \"" + name + "\" is mapped to invalid mouse wheel axis \"" + wheel + "\"");
						continue;
					}
					
					// Map control to mouse wheel axis
					ctx->input_event_router->add_mapping(input::mouse_wheel_mapping(control, nullptr, axis));
					
					ctx->logger->log("Mapped control \"" + name + "\" to mouse wheel axis " + wheel);
				}
				else if (it->contains("motion"))
				{
					std::string motion = (*it)["motion"].get<std::string>();
					input::mouse_motion_axis axis;
					if (motion == "x+")
						axis = input::mouse_motion_axis::positive_x;
					else if (motion == "x-")
						axis = input::mouse_motion_axis::negative_x;
					else if (motion == "y+")
						axis = input::mouse_motion_axis::positive_y;
					else if (motion == "y-")
						axis = input::mouse_motion_axis::negative_y;
					else
					{
						ctx->logger->warning("Control \"" + name + "\" is mapped to invalid mouse motion axis \"" + motion + "\"");
						continue;
					}
					
					// Map control to mouse motion axis
					ctx->input_event_router->add_mapping(input::mouse_motion_mapping(control, nullptr, axis));
					
					ctx->logger->log("Mapped control \"" + name + "\" to mouse motion axis " + motion);
				}
				else
				{
					ctx->logger->warning("Control \"" + name + "\" has invalid mouse mapping");
					continue;
				}
			}
			else if (device == "gamepad")
			{
				if (it->contains("button"))
				{
					// Parse gamepad button
					std::string button = (*it)["button"].get<std::string>();
					
					auto button_it = gamepad_button_map.find(button);
					if (button_it == gamepad_button_map.end())
					{
						ctx->logger->warning("Control \"" + name + "\" is mapped to invalid gamepad button \"" + button + "\"");
						continue;
					}
					
					// Map control to gamepad button
					ctx->input_event_router->add_mapping(input::gamepad_button_mapping(control, nullptr, button_it->second));
					
					ctx->logger->log("Mapped control \"" + name + "\" to gamepad button " + button);
				}
				else if (it->contains("axis"))
				{
					std::string axis = (*it)["axis"].get<std::string>();
					
					// Parse gamepad axis name
					const std::string axis_name = axis.substr(0, axis.length() - 1);
					auto axis_it = gamepad_axis_map.find(axis_name);
					if (axis_it == gamepad_axis_map.end())
					{
						ctx->logger->warning("Control \"" + name + "\" is mapped to invalid gamepad axis \"" + axis_name + "\"");
						continue;
					}
					
					// Parse gamepad axis sign
					const char axis_sign = axis.back();
					if (axis_sign != '-' && axis_sign != '+')
					{
						ctx->logger->warning("Control \"" + name + "\" is mapped to gamepad axis with invalid sign \"" + axis_sign + "\"");
						continue;
					}
					bool axis_negative = (axis_sign == '-');
					
					// Map control to gamepad axis
					ctx->input_event_router->add_mapping(input::gamepad_axis_mapping(control, nullptr, axis_it->second, axis_negative));
					
					ctx->logger->log("Mapped control \"" + name + "\" to gamepad axis " + axis);
				}
				else
				{
					ctx->logger->log("Control \"" + name + "\" has invalid gamepad mapping");
					continue;
				}
			}
			else
			{
				ctx->logger->warning("Control \"" + name + "\" bound to unknown device \"" + device + "\"");
			}
		}
	}
	
	// Set gamepad deadzones
	float gamepad_leftx_activation_min = 0.0f;
	float gamepad_leftx_activation_max = 0.0f;
	float gamepad_lefty_activation_min = 0.0f;
	float gamepad_lefty_activation_max = 0.0f;
	float gamepad_rightx_activation_min = 0.0f;
	float gamepad_rightx_activation_max = 0.0f;
	float gamepad_righty_activation_min = 0.0f;
	float gamepad_righty_activation_max = 0.0f;
	float gamepad_lefttrigger_activation_min = 0.0f;
	float gamepad_lefttrigger_activation_max = 0.0f;
	float gamepad_righttrigger_activation_min = 0.0f;
	float gamepad_righttrigger_activation_max = 0.0f;
	bool gamepad_left_deadzone_cross = true;
	bool gamepad_right_deadzone_cross = true;
	float gamepad_left_deadzone_roundness = 0.0f;
	float gamepad_right_deadzone_roundness = 0.0f;
	input::gamepad_response_curve gamepad_leftx_response_curve = input::gamepad_response_curve::linear;
	input::gamepad_response_curve gamepad_lefty_response_curve = input::gamepad_response_curve::linear;
	input::gamepad_response_curve gamepad_rightx_response_curve = input::gamepad_response_curve::linear;
	input::gamepad_response_curve gamepad_righty_response_curve = input::gamepad_response_curve::linear;
	input::gamepad_response_curve gamepad_lefttrigger_response_curve = input::gamepad_response_curve::linear;
	input::gamepad_response_curve gamepad_righttrigger_response_curve = input::gamepad_response_curve::linear;
	
	if (ctx->config->contains("gamepad_leftx_activation_min"))
		gamepad_leftx_activation_min = (*ctx->config)["gamepad_leftx_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_leftx_activation_max"))
		gamepad_leftx_activation_max = (*ctx->config)["gamepad_leftx_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_lefty_activation_min"))
		gamepad_lefty_activation_min = (*ctx->config)["gamepad_lefty_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_lefty_activation_max"))
		gamepad_lefty_activation_max = (*ctx->config)["gamepad_lefty_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_rightx_activation_min"))
		gamepad_rightx_activation_min = (*ctx->config)["gamepad_rightx_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_rightx_activation_max"))
		gamepad_rightx_activation_max = (*ctx->config)["gamepad_rightx_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_righty_activation_min"))
		gamepad_righty_activation_min = (*ctx->config)["gamepad_righty_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_righty_activation_max"))
		gamepad_righty_activation_max = (*ctx->config)["gamepad_righty_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_lefttrigger_activation_min"))
		gamepad_lefttrigger_activation_min = (*ctx->config)["gamepad_lefttrigger_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_lefttrigger_activation_max"))
		gamepad_lefttrigger_activation_max = (*ctx->config)["gamepad_lefttrigger_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_righttrigger_activation_min"))
		gamepad_righttrigger_activation_min = (*ctx->config)["gamepad_righttrigger_activation_min"].get<float>();
	if (ctx->config->contains("gamepad_righttrigger_activation_max"))
		gamepad_righttrigger_activation_max = (*ctx->config)["gamepad_righttrigger_activation_max"].get<float>();
	if (ctx->config->contains("gamepad_left_deadzone_cross"))
		gamepad_left_deadzone_cross = (*ctx->config)["gamepad_left_deadzone_cross"].get<bool>();
	if (ctx->config->contains("gamepad_right_deadzone_cross"))
		gamepad_right_deadzone_cross = (*ctx->config)["gamepad_right_deadzone_cross"].get<bool>();
	if (ctx->config->contains("gamepad_left_deadzone_roundness"))
		gamepad_left_deadzone_roundness = (*ctx->config)["gamepad_left_deadzone_roundness"].get<float>();
	if (ctx->config->contains("gamepad_right_deadzone_roundness"))
		gamepad_right_deadzone_roundness = (*ctx->config)["gamepad_right_deadzone_roundness"].get<float>();
	if (ctx->config->contains("gamepad_leftx_response_curve"))
		gamepad_leftx_response_curve = parse_response_curve((*ctx->config)["gamepad_leftx_response_curve"].get<std::string>());
	if (ctx->config->contains("gamepad_leftx_response_curve"))
		gamepad_leftx_response_curve = parse_response_curve((*ctx->config)["gamepad_leftx_response_curve"].get<std::string>());
	if (ctx->config->contains("gamepad_rightx_response_curve"))
		gamepad_rightx_response_curve = parse_response_curve((*ctx->config)["gamepad_rightx_response_curve"].get<std::string>());
	if (ctx->config->contains("gamepad_leftx_response_curve"))
		gamepad_leftx_response_curve = parse_response_curve((*ctx->config)["gamepad_leftx_response_curve"].get<std::string>());
	if (ctx->config->contains("gamepad_lefttrigger_response_curve"))
		gamepad_lefttrigger_response_curve = parse_response_curve((*ctx->config)["gamepad_lefttrigger_response_curve"].get<std::string>());
	if (ctx->config->contains("gamepad_righttrigger_response_curve"))
		gamepad_righttrigger_response_curve = parse_response_curve((*ctx->config)["gamepad_righttrigger_response_curve"].get<std::string>());
	
	for (input::gamepad* gamepad: ctx->app->get_gamepads())
	{
		gamepad->set_activation_threshold(input::gamepad_axis::left_x, gamepad_leftx_activation_min, gamepad_leftx_activation_max);
		gamepad->set_activation_threshold(input::gamepad_axis::left_y, gamepad_lefty_activation_min, gamepad_lefty_activation_max);
		gamepad->set_activation_threshold(input::gamepad_axis::right_x, gamepad_rightx_activation_min, gamepad_rightx_activation_max);
		gamepad->set_activation_threshold(input::gamepad_axis::right_y, gamepad_righty_activation_min, gamepad_righty_activation_max);
		gamepad->set_activation_threshold(input::gamepad_axis::left_trigger, gamepad_lefttrigger_activation_min, gamepad_lefttrigger_activation_max);
		gamepad->set_activation_threshold(input::gamepad_axis::right_trigger, gamepad_righttrigger_activation_min, gamepad_righttrigger_activation_max);
		gamepad->set_left_deadzone_cross(gamepad_left_deadzone_cross);
		gamepad->set_right_deadzone_cross(gamepad_right_deadzone_cross);
		gamepad->set_left_deadzone_roundness(gamepad_left_deadzone_roundness);
		gamepad->set_right_deadzone_roundness(gamepad_right_deadzone_roundness);
		gamepad->set_response_curve(input::gamepad_axis::left_x, gamepad_leftx_response_curve);
		gamepad->set_response_curve(input::gamepad_axis::left_y, gamepad_lefty_response_curve);
		gamepad->set_response_curve(input::gamepad_axis::right_x, gamepad_rightx_response_curve);
		gamepad->set_response_curve(input::gamepad_axis::right_y, gamepad_righty_response_curve);
		gamepad->set_response_curve(input::gamepad_axis::left_trigger, gamepad_lefttrigger_response_curve);
		gamepad->set_response_curve(input::gamepad_axis::right_trigger, gamepad_righttrigger_response_curve);
	}
	
	// Toggle fullscreen
	ctx->controls["toggle_fullscreen"]->set_activated_callback
	(
		[ctx]()
		{
			bool fullscreen = !ctx->app->is_fullscreen();
			
			ctx->app->set_fullscreen(fullscreen);
			
			if (!fullscreen)
			{
				int2 resolution;
				resolution.x = (*ctx->config)["windowed_resolution"][0].get<int>();
				resolution.y = (*ctx->config)["windowed_resolution"][1].get<int>();
				
				ctx->app->resize_window(resolution.x, resolution.y);
			}
			
			(*ctx->config)["fullscreen"] = fullscreen;
		}
	);
	
	// Screenshot
	ctx->controls["screenshot"]->set_activated_callback
	(
		[ctx]()
		{
			std::string path = ctx->screenshots_path + "antkeeper-" + timestamp() + ".png";
			ctx->app->save_frame(path);
		}
	);
	
	// Menu back
	ctx->controls["menu_back"]->set_activated_callback
	(
		std::bind(&application::close, ctx->app, 0)
	);
}

static input::gamepad_response_curve parse_response_curve(const std::string& curve)
{
	if (curve == "square")
		return input::gamepad_response_curve::square;
	else if (curve == "cube")
		return input::gamepad_response_curve::cube;
	return input::gamepad_response_curve::linear;
}

void cosmogenesis(game::context* ctx)
{
	// Init time
	const double time = 0.0;
	ctx->astronomy_system->set_universal_time(time);
	ctx->orbit_system->set_universal_time(time);
	
	// Create sun
	ctx->logger->push_task("Creating the sun");
	try
	{
		heliogenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Create planet
	ctx->logger->push_task("Creating the planet");
	try
	{
		planetogenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Create moon
	ctx->logger->push_task("Creating the moon");
	try
	{
		selenogenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Create fixed stars
	ctx->logger->push_task("Creating fixed stars");
	try
	{
		extrasolar_heliogenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
	
	// Create ant colony
	ctx->logger->push_task("Creating ant colony");
	try
	{
		colonigenesis(ctx);
	}
	catch (...)
	{
		ctx->logger->pop_task(EXIT_FAILURE);
		throw;
	}
	ctx->logger->pop_task(EXIT_SUCCESS);
}

void heliogenesis(game::context* ctx)
{
	// Create solar entity
	entity::id sun_eid = ctx->entity_registry->create();
	ctx->entities["sun"] = sun_eid;
	
	// Assign solar celestial body component
	entity::component::celestial_body body;
	body.radius = 6.957e+8;
	body.axial_tilt = math::radians(0.0);
	body.axial_rotation = math::radians(0.0);
	body.angular_frequency = math::radians(0.0);
	ctx->entity_registry->assign<entity::component::celestial_body>(sun_eid, body);
	
	// Assign solar orbit component
	entity::component::orbit orbit;
	orbit.elements.a = 0.0;
	orbit.elements.e = 0.0;
	orbit.elements.i = math::radians(0.0);
	orbit.elements.raan = math::radians(0.0);
	orbit.elements.w = math::radians(0.0);
	orbit.elements.ta = math::radians(0.0);
	ctx->entity_registry->assign<entity::component::orbit>(sun_eid, orbit);
	
	// Assign solar blackbody component
	entity::component::blackbody blackbody;
	blackbody.temperature = 5778.0;
	ctx->entity_registry->assign<entity::component::blackbody>(sun_eid, blackbody);
	
	// Assign solar transform component
	entity::component::transform transform;
	transform.local = math::identity_transform<float>;
	transform.warp = true;
	ctx->entity_registry->assign<entity::component::transform>(sun_eid, transform);
	
	// Create direct sun light scene object
	scene::directional_light* sun_direct = new scene::directional_light();
	
	// Create ambient sun light scene object
	scene::ambient_light* sun_ambient = new scene::ambient_light();
	sun_ambient->set_color({1, 1, 1});
	sun_ambient->set_intensity(0.0f);
	sun_ambient->update_tweens();
	
	// Add sun light scene objects to surface scene
	ctx->surface_scene->add_object(sun_direct);
	ctx->surface_scene->add_object(sun_ambient);
	
	// Pass direct sun light scene object to shadow map pass and astronomy system
	ctx->surface_shadow_map_pass->set_light(sun_direct);
	ctx->astronomy_system->set_sun_light(sun_direct);
}

void planetogenesis(game::context* ctx)
{
	// Create planetary entity
	entity::id planet_eid = ctx->entity_registry->create();
	ctx->entities["planet"] = planet_eid;
	
	// Assign planetary celestial body component
	entity::component::celestial_body body;
	body.radius = 6.3781e6;
	body.axial_tilt = math::radians(23.4393);
	body.axial_rotation = math::radians(280.46061837504);
	body.angular_frequency = math::radians(360.9856122880876128);
	ctx->entity_registry->assign<entity::component::celestial_body>(planet_eid, body);
	
	// Assign planetary orbit component
	entity::component::orbit orbit;
	orbit.elements.a = 1.496e+11;
	orbit.elements.e = 0.01671123;
	orbit.elements.i = math::radians(-0.00001531);
	orbit.elements.raan = math::radians(0.0);
	const double longitude_periapsis = math::radians(102.93768193);
	orbit.elements.w = longitude_periapsis - orbit.elements.raan;
	orbit.elements.ta = math::radians(100.46457166) - longitude_periapsis;
	ctx->entity_registry->assign<entity::component::orbit>(planet_eid, orbit);
	
	// Assign planetary terrain component
	entity::component::terrain terrain;
	terrain.elevation = [](double, double) -> double
	{
		//return math::random<double>(0.0, 1.0);
		return 0.0;
	};
	terrain.max_lod = 0;
	terrain.patch_material = nullptr;
	ctx->entity_registry->assign<entity::component::terrain>(planet_eid, terrain);
	
	// Assign planetary atmosphere component
	entity::component::atmosphere atmosphere;
	atmosphere.exosphere_altitude = 65e3;
	atmosphere.index_of_refraction = 1.000293;
	atmosphere.rayleigh_density = 2.545e25;
	atmosphere.rayleigh_scale_height = 8000.0;
	atmosphere.mie_density = 14.8875;
	atmosphere.mie_scale_height = 1200.0;
	atmosphere.mie_anisotropy = 0.8;
	ctx->entity_registry->assign<entity::component::atmosphere>(planet_eid, atmosphere);
	
	// Assign planetary transform component
	entity::component::transform transform;
	transform.local = math::identity_transform<float>;
	transform.warp = true;
	ctx->entity_registry->assign<entity::component::transform>(planet_eid, transform);
	
	// Pass planet to astronomy system as reference body
	ctx->astronomy_system->set_reference_body(planet_eid);
	
	// Load sky model
	ctx->surface_sky_pass->set_sky_model(ctx->resource_manager->load<model>("sky-dome.mdl"));
}

void selenogenesis(game::context* ctx)
{
	// Create lunar entity
	entity::id moon_eid = ctx->entity_registry->create();
	ctx->entities["moon"] = moon_eid;
	
	// Pass moon model to sky pass
	ctx->surface_sky_pass->set_moon_model(ctx->resource_manager->load<model>("moon.mdl"));
}

void extrasolar_heliogenesis(game::context* ctx)
{
	// Load star catalog
	string_table* star_catalog = ctx->resource_manager->load<string_table>("stars.csv");
	
	// Allocate star catalog vertex data
	std::size_t star_count = 0;
	if (star_catalog->size() > 0)
		star_count = star_catalog->size() - 1;
	std::size_t star_vertex_size = 7;
	std::size_t star_vertex_stride = star_vertex_size * sizeof(float);
	float* star_vertex_data = new float[star_count * star_vertex_size];
	float* star_vertex = star_vertex_data;
	
	// Build star catalog vertex data
	for (std::size_t i = 1; i < star_catalog->size(); ++i)
	{
		const string_table_row& catalog_row = (*star_catalog)[i];
		
		double ra = 0.0;
		double dec = 0.0;
		double vmag = 0.0;
		double bv_color = 0.0;
		
		// Parse star catalog entry
		try
		{
			ra = std::stod(catalog_row[1]);
			dec = std::stod(catalog_row[2]);
			vmag = std::stod(catalog_row[3]);
			bv_color = std::stod(catalog_row[4]);
		}
		catch (const std::exception& e)
		{
			continue;
		}
		
		// Convert right ascension and declination from degrees to radians
		ra = math::wrap_radians(math::radians(ra));
		dec = math::wrap_radians(math::radians(dec));
		
		// Transform spherical equatorial coordinates to rectangular equatorial coordinates
		double3 position_bci = geom::spherical::to_cartesian(double3{1.0, dec, ra});
		
		// Transform coordinates from equatorial space to inertial space
		physics::frame<double> bci_to_inertial = physics::orbit::inertial::to_bci({0, 0, 0}, 0.0, math::radians(23.4393)).inverse();
		double3 position_inertial = bci_to_inertial * position_bci;
		
		// Convert color index to color temperature
		double cct = color::index::bv_to_cct(bv_color);
		
		// Calculate XYZ color from color temperature
		double3 color_xyz = color::cct::to_xyz(cct);
		
		// Transform XYZ color to ACEScg colorspace
		double3 color_acescg = color::xyz::to_acescg(color_xyz);
		
		// Convert apparent magnitude to irradiance (W/m^2)
		double vmag_irradiance = std::pow(10.0, 0.4 * (-vmag - 19.0 + 0.4));
		
		// Convert irradiance to illuminance
		double vmag_illuminance = vmag_irradiance * (683.0 * 0.14);
		
		// Scale color by illuminance
		double3 scaled_color = color_acescg * vmag_illuminance;
		
		// Build vertex
		*(star_vertex++) = static_cast<float>(position_inertial.x);
		*(star_vertex++) = static_cast<float>(position_inertial.y);
		*(star_vertex++) = static_cast<float>(position_inertial.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>(vmag);
	}
	
	// Unload star catalog
	ctx->resource_manager->unload("stars.csv");
	
	// Allocate stars model
	model* stars_model = new model();
	
	// Resize model VBO and upload vertex data
	gl::vertex_buffer* vbo = stars_model->get_vertex_buffer();
	vbo->resize(star_count * star_vertex_stride, star_vertex_data);
	
	// Free star catalog vertex data
	delete[] star_vertex_data;
	
	// Bind vertex attributes to model VAO
	gl::vertex_array* vao = stars_model->get_vertex_array();
	std::size_t vao_offset = 0;
	vao->bind_attribute(VERTEX_POSITION_LOCATION, *vbo, 3, gl::vertex_attribute_type::float_32, star_vertex_stride, 0);
	vao_offset += 3;
	vao->bind_attribute(VERTEX_COLOR_LOCATION, *vbo, 4, gl::vertex_attribute_type::float_32, star_vertex_stride, sizeof(float) * vao_offset);
	
	// Load star material
	material* star_material = ctx->resource_manager->load<material>("fixed-star.mtl");
	
	// Create model group
	model_group* stars_model_group = stars_model->add_group("stars");
	stars_model_group->set_material(star_material);
	stars_model_group->set_drawing_mode(gl::drawing_mode::points);
	stars_model_group->set_start_index(0);
	stars_model_group->set_index_count(star_count);
	
	// Pass stars model to sky pass
	ctx->surface_sky_pass->set_stars_model(stars_model);
}

void colonigenesis(game::context* ctx)
{}

} // namespace loading
} // namespace state
} // namespace game