Hexagon engine ECS concept

hxecs.cpp

#include <iostream>

using Hx::ECS::ECSContext;
using Hx::ECS::EntityManager;
using Hx::ECS::Entity;
using Hx::ECS::World;
using Hx::ECS::System;
using Hx::Components::Position2D;
using Hx::Components::Direction2D;
using Hx::Components::Sprite2D;
using Hx::Systems::Sprite2DSystem;
using Hx::Events::KeyboardEvent;
using Hx::Events::EventHandler;
using Hx::Resource::Receiver;
using Hx::Input::Keyboard;

struct Playable
{
	Playable() {}
};

struct PlayableSystem : public System<PlayableSystem>, public Observer<PlayableSystem>
{	
	void Initialize(const EventManager& eventMgr) override
	{
		eventMgr.RegisterObserver<KeyboardEvent>(this->GetSystemInstance());
	}
	
	void Update(EntityManager& entities, EventManager& events, double dt) override
	{
	}
	
	void Notify(EntityManager& entities, EventManager& events, const KeyboardEvent& e)
	{
		for(Entity entity : entities.WithComponents<Playable>())
		{
			switch(kb.key) // switch key
			{
			case Keyboard::W:
				// move entities forward
			case Keyboard::S:
				// move entities backward
			case Keyboard::A:
				// move entities left
			case Keyboard::D:
				// move entities right
			}
		}
	}
};

class MyWorld : public World
{
public:
	MyWorld(ECSContext& ctx) :
		World(ctx)
	{
		EntityManager& Entities = GetEntityManager();
		
		// entity 1 (this entity is playable)
		Entity e = this->Entities.Create();
		e.Assign<Position2D>(50, 50);
		e.Assign<Direction2D>(0, 0);
		e.Assign<Sprite2D>(ResourceManager::LoadImage("ent0.png"));
		e.Assign<Playable>(true);
		
		// entity 2
		e = this->Entities.Create();
		e.Assign<Position2D>(100, 50);
		e.Assign<Direction2D>(0, 0);
		e.Assign<Sprite2D>(ResourceManager::LoadImage("ent1.png"));
	}
	
	void Update(double dt) override
	{
	}
	
	void Render(double dt) override
	{
		GetContext().Update<Sprite2DSystem>();
	}
};

// .. game initialization
ECSContext ctx;
ctx.RegisterSystem<Sprite2DSystem>();
ctx.RegisterSystem<PlayableSystem>();

MyWorld world(ctx);

// .. update function
ctx.GetEventManager().BroadcastEvents(this->GetEvents()); // Broadcast default events (keyboard events, mouse events, etc), this will notify all observers

// .. render function
world.Render(dt);