I'm currently trying to make a Minecraft Clone using OpenGL and using the ECS pattern. I didn't quite understood yet why I need the "Systems" when I already have components. My current structure I'm planing to use is this:
My main problem is that I don't really know how to store the Entitys. If I for example want to attack and check which Entity I did hit then I would need to iterate through all Entity stored in my vector<GameObject> in the World Class and check if it got the Health Component and then decrease the health. Which doesn't seem very clever to me as I will probably have multiple thousands Entitys alone by the Blocks in the chunks. I did read some stuff about Handlers but didn't understood how they work or should solve the problem of iterating through all Entitys who could possible need to be called to Receive Damage. Can anyone help me?