fix: World adds and removes now detached from tick loop

src/sim/af_spawner.cpp

@@ -2,7 +2,9 @@
 
 void dxd::sim::AFSpawner::tick(float timestep, World *world)
 {
-	if (_next_spawn-- == 0)
+	(void)timestep;
+
+	if (_next_spawn-- != 0)
 		return;
 
 	_next_spawn = 60 + SDL_rand(120);

src/sim/af_spawner.hpp

@@ -23,7 +23,7 @@ public:
 	}
 
 	void tick(float timestep, World *world) override;
-	void draw(Renderer *rend) override {}
+	void draw(Renderer *rend) override { (void)rend; }
 };
 
 } // namespace dxd::sim

src/sim/aircraft.cpp

@@ -2,6 +2,8 @@
 
 void dxd::sim::Aircraft::tick(float timestep, World *world)
 {
+	(void)world;
+
 	_position = _position + polar_to_vec2(_direction, _speed) * timestep;
 }
 

src/sim/airfield.cpp

@@ -3,9 +3,11 @@
 
 void dxd::sim::Airfield::tick(float timestep, World *world)
 {
+	(void)timestep;
+
 	if (--_ttl == 0)
 	{
-		//world->remove_obj(this);
+		world->remove_obj(this);
 		return;
 	}
 

src/sim/world.cpp

@@ -6,6 +6,24 @@ void dxd::sim::World::tick(float timestep)
 	{
 		obj->tick(timestep, this);
 	}
+
+	for (auto remove : _pending_removes)
+	{
+		for (auto it = _objs.begin(); it != _objs.end(); ++it)
+		{
+			if (*it == remove)
+			{
+				_objs.erase(it);
+				break;
+			}
+		}
+	}
+
+	for (auto add : _pending_adds)
+		_objs.push_back(add);
+
+	_pending_adds.clear();
+	_pending_removes.clear();
 }
 
 void dxd::sim::World::draw(Renderer *rend)

src/sim/world.hpp

@@ -15,25 +15,19 @@ class World
 private:
 	vec2 _size;
 	std::vector<WorldObject*> _objs;
+	std::vector<WorldObject*> _pending_removes;
+	std::vector<WorldObject*> _pending_adds;
 
 public:
 	World(vec2 size) : _size(size)
 	{
 		_objs = std::vector<WorldObject*>();
+		_pending_adds = std::vector<WorldObject*>();
+		_pending_removes = std::vector<WorldObject*>();
 	}
 
-	void add_obj(WorldObject *obj) { _objs.push_back(obj); }
-	void remove_obj(WorldObject *obj)
-	{
-		for (auto it = _objs.begin(); it != _objs.end(); ++it)
-		{
-			if (*it == obj)
-			{
-				_objs.erase(it);
-				break;
-			}
-		}
-	}
+	void add_obj(WorldObject *obj) { _pending_adds.push_back(obj); }
+	void remove_obj(WorldObject *obj) { _pending_removes.push_back(obj); }
 
 	void tick(float timestep);
 	void draw(Renderer *rend);