xy::CallbackSystem Class Reference

Performs a given callback function on an entity. This is useful for behaviour code on entities which aren't used often. For example when a single entity of a type exists and is used rarely it can mean a lot of overhead writing a specific system and component for behaviour which is not often employed. In these cases it's easier to attach a Callback component and supply a function with entity specific behaviour. Overuse of this system is not recommended, however, as there is a certain amount of overhead in calling the behavioural functions, so this system should be reserved for specific cases where it makes sense or for rapid prototying of ideas that may or may not be expanded to a full system. More...

#include <CallbackSystem.hpp>

Inheritance diagram for xy::CallbackSystem:

Public Member Functions
	CallbackSystem (MessageBus &)
void	process (float) override
	Implement this for system specific processing to entities.
Public Member Functions inherited from xy::System
	System (MessageBus &mb, UniqueType t)
	Constructor. Pass in a reference to the concrete implementation to generate a unique type ID for this system.
UniqueType	getType () const
	Returns the unique type ID of the system.
const std::vector< Entity > &	getEntities () const
	Returns a list of entities that this system is currently interested in.
void	addEntity (Entity)
	Adds an entity to the list to process.
void	removeEntity (Entity)
	Removes an entity from the list to process.
const ComponentMask &	getComponentMask () const
	Returns the component mask used to mask entities with corresponding components for this system to process.
virtual void	handleMessage (const Message &)
	Used to process any incoming system messages.
bool	isActive () const
	Returns true if the system is currently active. Systems can be activeated and deactivated with Scene::setSystemActive()
template<typename T >
void	requireComponent ()
template<typename T >
T *	postMessage (Message::ID id)

Additional Inherited Members
Public Types inherited from xy::System
using	Ptr = std::unique_ptr< System >
Protected Member Functions inherited from xy::System
template<typename T >
void	requireComponent ()
	Adds a component type to the list of components required by the system for it to be interested in a particular entity. This should only be used in the constructor of the System else types will not be registered.
std::vector< Entity > &	getEntities ()
virtual void	onEntityAdded (Entity)
	Optional callback performed when an entity is added.
virtual void	onEntityRemoved (Entity)
	Optional callback performed when an entity is removed.
template<typename T >
T *	postMessage (Message::ID id)
	Posts a message on the system wide message bus.
MessageBus &	getMessageBus ()
	Returns a reference to the MessageBus.
void	setScene (Scene &)
Scene *	getScene ()
	Returns a pointer to the scene to which this system belongs.

Detailed Description

Performs a given callback function on an entity. This is useful for behaviour code on entities which aren't used often. For example when a single entity of a type exists and is used rarely it can mean a lot of overhead writing a specific system and component for behaviour which is not often employed. In these cases it's easier to attach a Callback component and supply a function with entity specific behaviour. Overuse of this system is not recommended, however, as there is a certain amount of overhead in calling the behavioural functions, so this system should be reserved for specific cases where it makes sense or for rapid prototying of ideas that may or may not be expanded to a full system.