This ECS is heavily inspired from the Entityx component system. It is a much simpler and less efficient implementation, as it does not support dedicated pools for the different components, and only stores them on the heap and are directed to by pointers.

A future improvement would be to store the components in a contiguous area in memory, so that the iteration through them can be more efficient.

Structure

Entity

The EntityManager is the class that manages the entities, by allocating and deleting them as necessary. The Entity itself is just a handle, and does not contain any logic or data. It is just used to refer to the Entity when doing operations on it.

Components

These are just data that is associated with Entities, and it gets processed by the Systems when these are updated. The systems only process a few components at once, which separates the logic and makes it easy to develop the Systems and Components orthogonally.

Systems

These process the Components and update their state. This completely separates the data from the logic, and means that they can be tested independently. New systems can be created by inheriting from the BaseSystem, which provides an interface which then enables that system to be added to the main Engine through different types of Spaces.

Implementation

The Entity is just an unsigned int, which has a typedef called Entity, which is also what all the functions return.

The link between the components are managed by a templated ComponentMapper class, that links every entity with it's component. This way it is also to find out if an entity is part of a specific component, and that entity will never be processed in the system that only targets that component, which makes it much more efficient.