A type-safe entity type. More...

#include <CeresEngine/Entity/Entity.hpp>

Inheritance diagram for CeresEngine::EntityObject< Components >:

Classes
struct	_MaskObject
	A trait that contains the minimum necessary component mask for an entity to be an entity object of this type. More...

Public Types
using	ComponentSet = CeresEngine::ComponentSet< Components... >
	The component set for the entity object.

using	Type = EntityObject< Components... >
	Underlying EntityObject.

Public Member Functions
	EntityObject ()=default
	Creates a new entity object.

	EntityObject (std::nullptr_t) noexcept
	Creates a new empty entity.

	EntityObject (EntityManager &entityManager)
	Creates a new entity object attached to a entity manager.

	EntityObject (EntityManager &entityManager, const Entity &parent)
	Creates a new entity object attached to a entity manager.

	EntityObject (EntityManager &entityManager, String name)
	Creates a new entity object attached to a entity manager.

	EntityObject (EntityManager &entityManager, const Entity &parent, String name)
	Creates a new entity object attached to a entity manager.

template<typename... OtherComponents> requires (EntityObject<OtherComponents...>::ComponentSet::template includes<Components>&&...)
	EntityObject (const EntityObject< OtherComponents... > &entity)
	Creates a new entity object by down-casting other compatible entity object.

	EntityObject (const EntityObject &other) noexcept=default
	Creates a new entity by copying another.

EntityObject &	operator= (const EntityObject &other) noexcept=default
	Assing the contents of the entity by copying the contents of another.

CE_FLATTEN_INLINE decltype(auto)	operator-> () const
	Creates a new `ComponentAccessor` for this entity object.

UInt64	getHash () const
	Computes a hash that uniquely represents the entity object.

bool	compareHash (UInt64 &hash) const

Public Member Functions inherited from CeresEngine::Entity
	Entity () noexcept=default
	Creates a new empty entity.

	Entity (EntityManager &entityManager, EntityID id) noexcept
	Creates a new entity attached to a entity manager.

	Entity (std::nullptr_t) noexcept
	Creates a new empty entity.

Entity &	operator= (std::nullptr_t) noexcept
	Empties a `EntityObject`. The entity is not deallocated.

	Entity (const Entity &other) noexcept=default
	Creates a new entity by copying another.

Entity &	operator= (const Entity &other) noexcept=default
	Assing the contents of the entity by copying the contents of another.

bool	valid () const noexcept
	Checks if the entity is still valid.

Entity	copy () const
	Copies the entity and all its components.

template<typename Block >
Entity	copy (Block &&block) const
	Copies the entity and all its components. Executes `block` as.

void	destroy () const
	Destroys the entity.

AbstractComponent &	add (const ComponentType &type, const Box &initialValue=nullptr) const
	Adds a new component of the given `type`.

template<CComponent C, typename... Args>
C &	add (Args &&... args) const noexcept(std::is_nothrow_constructible_v< C, Args... >)
	Adds a new component.

template<CComponent C, typename Block , typename... Args>
C &	addWith (Block &&block, Args &&... args) const noexcept(std::is_nothrow_constructible_v< C, Args... >)
	Adds a new component and calls `block` with the added component.

template<CComponent C, typename... Args>
C &	set (Args &&... args) const noexcept(std::is_nothrow_constructible_v< C, Args... >)
	Sets a component.

void	remove (const ComponentType &type) const
	Removes a component of the given `type` from the entity.

template<CComponent C>
void	remove () const noexcept(std::is_nothrow_destructible_v< C >)
	Removes a component of type `C` from the entity.

AbstractComponent &	get (const ComponentType &type) const
	Gets a component of the given `type`.

template<CComponent C>
C &	get () const noexcept
	Gets a component of type `C`.

template<CComponent C0, CComponent C1, CComponent... Cs>
Tuple< C0 &, C1 &, Cs &... >	get () const noexcept
	Gets a set of components of types `C0`, `C1` and `Cs`.

AbstractComponent &	getOr (const ComponentType &type) const
	Gets a component of the given `type`.

template<CComponent C>
C &	getOr () const noexcept(std::is_nothrow_constructible_v< C >)
	Gets a component of type `C`.

template<CComponent C0, CComponent C1, CComponent... Cs>
Tuple< C0 &, C1 &, Cs &... >	getOr () const noexcept
	Gets a set of components of types `C0`, `C1` and `Cs`.

AbstractComponent *	getIf (const ComponentType &type) const
	Gets a component of the given `type`.

template<CComponent C>
C *	getIf () const noexcept
	Gets a component of type `C`.

template<CComponent C0, CComponent C1, CComponent... Cs>
Tuple< C0 , C1 , Cs *... >	getIf () const noexcept
	Gets a set of components of types `C0`, `C1` and `Cs`.

Vector< AbstractComponent * >	getComponents () const

bool	has (const ComponentType &type) const noexcept
	Checks if the entity has all components of the given `type`.

template<CComponent C, CComponent... Cs>
bool	has () const noexcept
	Checks if the entity has all components of types `Cs`.

void	clear () const
	Removes all components attached to the entity, without destroying the entity itself.

bool	empty () const noexcept
	Checks if the entity is empty (i.e.

template<typename E >
bool	is () const noexcept
	Checks if the entity matches the criteria to be considered a `E` entity object.

template<typename E >
E	as () const
	Converts the entity handle type into a `E` entity object.

template<typename... Cs>
EntityObject< Cs... >	having () const
	Converts the entity handle type into a `EntityObject<Cs...>` object.

template<typename E >
E	being () const noexcept
	Converts the entity handle type into a `E` entity object.

Entity	getParent () const noexcept
	Gets the parent entity.

template<typename P >
P	getParent () const noexcept
	Gets the parent entity of type `T`.

void	setParent (Entity parent) const
	Sets the parent entity.

const Vector< Entity > &	getChildren () const noexcept
	Gets the list of children entities.

template<typename T >
Generator< T >	getChildren () const noexcept
	Gets the list of children entities.

void	setChildren (const Vector< Entity > &children)
	Sets all entities as children of this entity.

StringView	getName () const noexcept
	Gets the name for the entity.

void	setName (String name) const
	Sets the name for the entity.

template<CEntityEvent E, typename... Args>
void	emit (Args &&... args) const
	Emits a event of type `E` to all event listeners.

template<CEntityEvent E>
void	emit (const E &event) const
	Emits a event of type `E` to all event listeners.

template<CEntityEvent E, typename Listener >
WeakEventConnection	on (Listener &&listener) const
	Subscribes a listener that waits for events from the entity.

template<CEntityAction A, typename... Args>
bool	canAct (Args &&... args) const
	Checks if the the entity is capable of acting on the given action `A`.

template<CEntityAction A, typename... Args>
decltype(auto)	act (Args &&... args) const
	Orders the entity to act on the action `A`.

template<typename T , CComponent Component>
auto	mutate (T Component::*ptr) const
	Accesses an element from an existing `Component`.

template<typename MutateFunc , typename T , CComponent Component>
decltype(auto)	mutate (MutateFunc &&func, T Component::*ptr) const
	Accesses an element from an existing `Component`.

template<typename T , CComponent Component>
const T &	read (const T Component::*ptr) const
	Accesses an element from an existing `Component`.

EntityID	getEntityID () const noexcept

EntityManager &	getEntityManager () const noexcept

	operator bool () const noexcept
	Checks if the entity is still valid.

Entity	operator[] (const EntityIndex childIndex) const

Entity	operator[] (const StringView childName) const

Static Public Member Functions
static EntityObject	make (Entity entity)
	Makes the `entity` an entity object by adding any missing component and casting it.

Static Public Attributes
template<typename C >
static constexpr bool	includes = ComponentSet::template includes<C>
	Checks if all `Components` are valid component types.

static const _MaskObject	mask

Private Member Functions
	EntityObject (EntityManager &entityManager, EntityID entityID)
	Creates a new entity object attached to a entity manager.

Friends
class	EntityManager

template<CComponent... ACs>
std::ostream &	operator<< (std::ostream &os, const EntityObject< ACs... > &entity)
	Compares two entities for equality.

Additional Inherited Members
Public Attributes inherited from CeresEngine::Entity
EntityManager *	entityManager = nullptr
	The owning entity manager.

EntityID	entityID = {}
	The entity ID.

Detailed Description

template<CComponent... Components>
class CeresEngine::EntityObject< Components >

A type-safe entity type.

This type can be used as-is or subclassed to offer higher type-safe guarantees. Subclasses however cannot add new data members to the entity as those won't be saved in the entity.

This class can act as a kind of mixin class than can be used to create entities that obligatorily have the given component types. The entity data can be read or mutated through it's operator->() that returns a special type that combines all Component::Accessor types for all the given Components.

It is guaranteed that a given EntityObject instance has all of the given components. Access to the underlying components can be done using the get() method although that is discouraged in favour of using the higher-level Component::Accessor interface using operator->().

The EntityObject instance itself doesn't store any data other than a reference to the owning EntityManager and it's EntityID. All data storage and persistence is delegated to a set of Components.

If defining a custom component type it is also recommended to implement a Component::Accessor type. This allows entity objects that use that component to offer a richer interface for users while delegating the internals of component data management to the Accessor implementation.

An entity object can be hashed if all it's 'Components' are also hashable. The hash can be calculated by calling getHash(). A helper function to check the previous hash and computing a new one is also available as compareHash() and can be used by systems such as the renderer to determine if an entity has changed since the last call.

Template Parameters

Components The components required by the entity object.

Member Typedef Documentation

◆ ComponentSet

template<CComponent... Components>

using CeresEngine::EntityObject< Components >::ComponentSet = CeresEngine::ComponentSet<Components...>

The component set for the entity object.

◆ Type

template<CComponent... Components>

using CeresEngine::EntityObject< Components >::Type = EntityObject<Components...>

Underlying EntityObject.

Used for creating Entity alias without a provided constructor

Constructor & Destructor Documentation

◆ EntityObject() [1/9]

template<CComponent... Components>

CeresEngine::EntityObject< Components >::EntityObject ( )

inlinedefault

template<CComponent... Components>

template<typename... OtherComponents>
requires (EntityObject<OtherComponents...>::ComponentSet::template includes<Components>&&...)

CeresEngine::EntityObject< Components >::EntityObject ( const EntityObject< OtherComponents... > & entity )

inline

Creates a new entity object by down-casting other compatible entity object.

Template Parameters

OtherComponents The components attached to the other entity object.

Parameters

entity The entity object to be down-casted from.

◆ EntityObject() [8/9]

template<CComponent... Components>

CeresEngine::EntityObject< Components >::EntityObject ( const EntityObject< Components > & other )

inlinedefaultnoexcept

Creates a new entity by copying another.

NOTE: this will only copy the entity handle, the components and the entity ID will still be the same.

Parameters

other The entity to copy from

◆ EntityObject() [9/9]

template<CComponent... Components>

CeresEngine::EntityObject< Components >::EntityObject	(	EntityManager &	entityManager,
		EntityID	entityID
	)

inlineprivate

Creates a new entity object attached to a entity manager.

Parameters

entityManager	The entity manager owning the entity
entityID	The entity ID

Member Function Documentation

◆ compareHash()

template<CComponent... Components>

bool CeresEngine::EntityObject< Components >::compareHash ( UInt64 & hash ) const

inline

◆ getHash()

template<CComponent... Components>

UInt64 CeresEngine::EntityObject< Components >::getHash ( ) const

inline

Computes a hash that uniquely represents the entity object.

Returns: A hash that uniquely represents the object.

◆ make()

template<CComponent... Components>

static EntityObject CeresEngine::EntityObject< Components >::make ( Entity entity )

inlinestatic

Makes the entity an entity object by adding any missing component and casting it.

Parameters

entity The entity to be made an entity object

Returns: The made entity object.

◆ operator->()

template<CComponent... Components>

CE_FLATTEN_INLINE decltype(auto) CeresEngine::EntityObject< Components >::operator-> ( ) const

inline

Creates a new ComponentAccessor for this entity object.

Returns: A component accessor for the entity object.

Returns: this. This allows the usage of operator-> when returning a ComponentAccessor by value.

◆ operator=()

template<CComponent... Components>

EntityObject & CeresEngine::EntityObject< Components >::operator= ( const EntityObject< Components > & other )

inlinedefaultnoexcept

Assing the contents of the entity by copying the contents of another.

NOTE: this will only copy the entity handle, the components and the entity ID will still be the same.

Parameters

other The entity to copy from

Returns: This

Friends And Related Symbol Documentation

◆ EntityManager

template<CComponent... Components>

friend class EntityManager

friend

◆ operator<<

template<CComponent... Components>

template<CComponent... ACs>

std::ostream & operator<<	(	std::ostream &	os,
		const EntityObject< ACs... > &	entity
	)

friend

Compares two entities for equality.

Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two entities can be considered equal Compares two entities for inequality. Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two IDs can be considered equal Compares two entities for equality. Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two entities can be considered equal Compares two entities for inequality. Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two IDs can be considered equal Compares two entities for equality. Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two entities can be considered equal Compares two entities for inequality. Two entity are considered equal iff their index and version match and they are managed by the same entity manager.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the two IDs can be considered equal Checks if a entity is empty.

Parameters

a	The left hand side operator argument
b	The right hand side operator argument

Returns: True if the entity is empty Prints a string representation of the Entity

Parameters

os	The output stream to print to
entity	The entity ID to be printed

Returns: The given os

Member Data Documentation

◆ includes

template<CComponent... Components>

template<typename C >

constexpr bool CeresEngine::EntityObject< Components >::includes = ComponentSet::template includes<C>

inlinestaticconstexpr

Checks if all Components are valid component types.

A trait that checks if the component type C is included in the entity object type

Template Parameters

C	the component type

◆ mask

template<CComponent... Components>

const _MaskObject CeresEngine::EntityObject< Components >::mask

inlinestatic

The documentation for this class was generated from the following file:

/Users/Rogiel/Developer/CeresEngine/Engine/Sources/CeresEngine/Entity/Entity.hpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ ComponentSet

◆ Type

Constructor & Destructor Documentation

◆ EntityObject() [1/9]

◆ EntityObject() [2/9]

◆ EntityObject() [3/9]

◆ EntityObject() [4/9]

◆ EntityObject() [5/9]

◆ EntityObject() [6/9]

◆ EntityObject() [7/9]

◆ EntityObject() [8/9]

◆ EntityObject() [9/9]

Member Function Documentation

◆ compareHash()

◆ getHash()

◆ make()

◆ operator->()

◆ operator=()

Friends And Related Symbol Documentation

◆ EntityManager

◆ operator<<

Member Data Documentation

◆ includes

◆ mask