gistfile1.cpp

class renderer {
public:
	enum class action {
		view_add, view_remove, view_activate,
		model_matrix_add, model_matrix_remove,
		vb_add, vb_remove,
	};

private:
	static std::atomic<std::queue<std::pair<action, entity_id>>*> global_queue;
	std::queue<std::pair<action, entity_id>>* local_queue;

	void process_queue() {
		global_queue.exchange(this->local_queue);

		while (!this->local_queue->empty()) {
			auto action_to_perform = this->local_queue->front();
			this->local_queue->pop();

			switch (action_to_perform.first) {
			case action::view_add:
				update_view_matrix(action_to_perform.second);
				break;
			case action::view_remove:
				this->views.erase(action_to_perform.second);
				break;
			case action::view_activate:
				this->current_view = action_to_perform.second;
				break;
			case action::model_matrix_add:
				add_model_matrix(action_to_perform.second);
				break;
			case action::model_matrix_remove:
				remove_model_matrix(action_to_perform.second);
				break;
			}
		}
	}

	void update(double time_delta) {
		process_queue();
	}

	void add_view(entity_id eid) {
		renderer::global_queue->push(std::make_pair(action::view_add, entity_id));
	}
};