feat: Very broken trigonometry but planes turn

src/sim/airfield.hpp

@@ -14,14 +14,17 @@ private:
 	vec2 _position;
 	int _ttl;
 	int _next_spawn;
+	float _rw_heading;
 
 	const int _MIN_TAKEOFF_DELAY = 240;
 	const int _MAX_TAKEOFF_DELAY = 600;
+	const int _WR_LENGTH = 6;
 
 public:
-	Airfield(vec2 position, int ttl) : _position(position), _ttl(ttl)
+	Airfield(vec2 position, int ttl, float rw_heading)
+		: _position(position), _ttl(ttl), _rw_heading(rw_heading)
 	{
-		_next_spawn = 30;
+		_next_spawn = _MIN_TAKEOFF_DELAY;
 	}
 
 	void tick(float timestep, World *world) override;