feat: Approaches and referenced airfields

src/dxd_math.cpp

@@ -42,6 +42,11 @@ bool operator>(vec2 const &a, vec2 const &b)
     return a.x > b.x && a.y > b.y;
 }
 
+bool operator==(vec2 const &a, vec2 const &b)
+{
+    return a.x == b.x && a.y == b.y;
+}
+
 bool operator<(vec2i const &a, vec2i const &b)
 {
     return a.x < b.x && a.y < b.y;

src/dxd_math.hpp

@@ -26,6 +26,7 @@ vec2 operator*(vec2 const &a, float const &b);
 vec2 operator/(vec2 const &a, float const &b);
 bool operator<(vec2 const &a, vec2 const &b);
 bool operator>(vec2 const &a, vec2 const &b);
+bool operator==(vec2 const &a, vec2 const &b);
 
 // vec2i operators
 bool operator<(vec2i const &a, vec2i const &b);

src/sim/af_spawner.cpp

@@ -56,6 +56,8 @@ dxd::sim::Airfield *dxd::sim::AFSpawner::get_random_airfield(Airfield *exclude)
 		auto it = _airfields.begin();
 		for (; it != _airfields.end() && sel; ++it, --sel);
 		af = it->second;
+		if (!af->is_active())
+			af = exclude;
 	} while(af == exclude);
 
 	return af;

src/sim/af_spawner.hpp

@@ -19,7 +19,7 @@ private:
 	int _next_spawn;
 
 	const int _SPAWN_BOUNDS = 150;
-	const int _GRID_STRIDE = 4;
+	const int _GRID_STRIDE = 10;
 	const int _GRID_MARGIN = 5;
 	const int _GRID_BOUNDS = (_SPAWN_BOUNDS - _GRID_MARGIN * 2) / _GRID_STRIDE;
 	const float _GRID_JITTER = (float)_GRID_STRIDE * 0.4f;

src/sim/aircraft.cpp

@@ -3,7 +3,17 @@
 
 void dxd::sim::Aircraft::tick(float timestep, World *world)
 {
-	(void)world;
+	// Refactor into own function
+	float target_dist = norm2(_target - _position);
+	if (target_dist < _TARGET_REACHED_DIST2)
+	{
+		if (_target == _destination->get_position())
+		{
+			_destination->arrived_at();
+			world->remove_obj(this);
+		}
+		_target = _destination->get_position();
+	}
 
 	float target_angle = vec2_angle(_target - _position);
 	float target_deviation = target_angle - _direction;

src/sim/aircraft.hpp

@@ -2,6 +2,7 @@
 
 #include "../dxd_math.hpp"
 #include "world_object.hpp"
+#include "airfield.hpp"
 
 namespace dxd::sim
 {
@@ -12,6 +13,7 @@ private:
 	vec2 _position;
 	float _direction;
 	float _speed;
+	Airfield *_destination;
 	vec2 _target;
 	int _trail_cooldown;
 
@@ -19,12 +21,16 @@ private:
 	const int _TRAIL_DURATION = 600;
 	const float _MAX_TURN_RATE = 0.3f;
 	const float _SPD_TO_KTS = 60.0f;
+	const float _TARGET_REACHED_DIST = 0.5f;
+	const float _TARGET_REACHED_DIST2 = _TARGET_REACHED_DIST*_TARGET_REACHED_DIST;
 
 public:
-	Aircraft(vec2 position, float direction, float speed, vec2 target)
-		: _position(position), _direction(direction), _speed(speed), _target(target)
+	Aircraft(vec2 position, float direction, float speed, Airfield *destination)
+		: _position(position), _direction(direction), _speed(speed), _destination(destination)
 	{
 		_trail_cooldown = _TRAIL_DELAY;
+		_target = destination->get_approach_point();
+		destination->going_to();
 	}
 
 	void tick(float timestep, World *world) override;

src/sim/airfield.cpp

@@ -5,10 +5,13 @@ void dxd::sim::Airfield::tick(float timestep, World *world)
 {
 	(void)timestep;
 
-	if (--_ttl == 0)
+	if (--_ttl <= 0)
+	{
+		if (_pending_arrivals == 0)
 		{
 			world->remove_obj(this);
 			//TODO: Free space in af_spawner
+		}
 		return;
 	}
 
@@ -17,9 +20,8 @@ void dxd::sim::Airfield::tick(float timestep, World *world)
 		vec2 pos = _position + polar_to_vec2(_rw_heading, _RW_LENGTH+0.5);
 
 		Airfield *target = _parent->get_random_airfield(this);
-		vec2 tgt_pos = target->get_position();
 
-		Aircraft *af = new Aircraft(pos, _rw_heading, 2.0f, tgt_pos);
+		Aircraft *af = new Aircraft(pos, _rw_heading, 2.0f, target);
 		world->add_obj(af);
 
 		_next_spawn = _MIN_TAKEOFF_DELAY + SDL_rand(_MAX_TAKEOFF_DELAY - _MIN_TAKEOFF_DELAY);
@@ -37,3 +39,8 @@ void dxd::sim::Airfield::draw(Renderer *rend)
 	vec2 b = _position + polar_to_vec2(_rw_heading, -_RW_LENGTH);
 	rend->line(a, b);
 }
+
+vec2 dxd::sim::Airfield::get_approach_point()
+{
+	return _position - polar_to_vec2(_rw_heading, _RW_LENGTH + _APPROACH_DIST);
+}

src/sim/airfield.hpp

@@ -20,9 +20,12 @@ private:
 	int _next_spawn;
 	float _rw_heading;
 
+	int _pending_arrivals;
+
 	int const _MIN_TAKEOFF_DELAY = 600;
 	int const _MAX_TAKEOFF_DELAY = 3000;
 	int const _RW_LENGTH = 6;
+	float const _APPROACH_DIST = 20.0f;
 
 public:
 	Airfield(AFSpawner *parent, vec2 position, int ttl, float rw_heading)
@@ -32,6 +35,10 @@ public:
 	}
 
 	vec2 get_position() { return _position; }
+	vec2 get_approach_point();
+	void going_to() { ++_pending_arrivals; }
+	void arrived_at() { --_pending_arrivals; }
+	bool is_active() { return _ttl > 0; }
 
 	void tick(float timestep, World *world) override;
 	void draw(Renderer *rend) override;