orbital_shipping/src/game.h

#pragma once

#include <glm/glm.hpp>
using glm::vec3;

#include "tangerine.h"
#include "orbits.h"


#define DEFAULT_ORBIT_VERTICES 256

const vec3 DEFAULT_ELLIPSE_COLOR = vec3(0.5, 0.5, 0.5);
const vec3 SELECTED_ELLIPSE_COLOR = vec3(0.7, 0.2, 0.2);


struct Ellipse3D
{
	vec3* vertices;
	uint vert_count;
};

enum struct ManeuverType
{
	PROGRADE,
	RETROGRADE,
	INCLINATION_CHANGE,
	GENERAL_PLANE_CHANGE,
	OTHER,
	VECTOR_TYPE_COUNT
};

struct ManeuverNode
{
	double true_anomaly;
	vec3 impulse_vector;
	ManeuverType impulse_type;
	double impulse_delta_v;
	// TODO: thrust calculations

	bool active;
};

struct GameOrbit
{
	TwoBodySystem system;
	Ellipse3D e3d;
	// TODO: multiple maneuvers
	ManeuverNode maneuver;

	Entity* grav_body;
	Entity* ellipse_entity;
	Entity* satellite_entity;
	bool in_use;
	bool selected;
};

struct GameState
{
	bool running;
	MemoryArena* arena;

	u64 game_time_ms;
	u64 sim_time_ms;
	float sim_speed;

	GameOrbit* orbits;
	u32 num_orbits;
	u32 max_orbits;

	GameOrbit* last_selected_orbit;
};

GameOrbit* getFreeOrbit(GameState* gs);

GameOrbit* getSelectedOrbit(GameState* gs);

void disableGameOrbit(GameState* gs, GameOrbit* orbit);

double getTimeStep(GameState* gs);

// NOTE: create vertices for a 3d ellipse
// 	all vertices are in the x/y plane with z = 0
Ellipse3D ellipse3DInit(EllipseParameters ep, uint vert_count);

void ellipse3DUpdate(EllipseParameters ep, Ellipse3D& e3d);

void selectOrbit(GameState* gs, GameOrbit* orbit);

bool addManeuver(GameOrbit* orbit, double anomaly, vec3 impulse_vector,
		double impulse_delta_v);

void removeManeuver(GameOrbit* orbit);

bool testManeuverStep(const ManeuverNode& maneuver,
		double previous_theta,
		double next_theta);

void applyManeuver(GameOrbit* orbit);