Engine::Entity Class Reference

Wrapper class providing a convenient interface for entity manipulation with the Core. Entity acts as a handle to an entity in the registry, combining a Core reference with an EntityId. It provides utility methods to add, remove, and query components, and maintains context relative to the Core it belongs to. More...

#include <Entity.hpp>

Public Member Functions
	Entity (Core &core, EntityId entityId)
	Create an Entity from EntityId and the Core it belongs to.
	~Entity ()=default
	Default destructor for Entity. It does not perform any special cleanup, as the Core is responsible for managing the entity's lifecycle.
bool	IsAlive () const
	Check if the entity is alive.
EntityId	Id () const
	Get the EntityId associated with this Entity.
	explicit (false) operator EntityId() const
	Implicit conversion operator to EntityId.
void	Kill ()
	Kill the entity, removing all components and making it invalid. After calling this method, the EntityId will no longer correspond to a valid entity in the Core's registry, and the Entity will be considered dead.
template<typename TComponent>
decltype(auto)	AddComponent (TComponent &&component)
	Add a component to an entity.
template<typename TComponent, typename... TArgs>
decltype(auto)	AddComponent (TArgs &&...args)
	Add a component to an entity.
template<typename TComponent, typename... TArgs>
decltype(auto)	AddComponentIfNotExists (TArgs &&...args)
	Add a component to an entity if it does not already exist.
template<typename TTempComponent, typename... TArgs>
decltype(auto)	AddTemporaryComponent (TArgs &&...args)
	Add a temporary component to an entity. Temporary component are removed when calling RemoveTemporaryComponents system.
template<typename TComponent>
void	RemoveComponent ()
	Remove a component from an entity.
template<typename... TComponent>
bool	HasComponents () const
	Check if entity have one or multiple component's type.
template<typename... TComponent>
decltype(auto)	GetComponents ()
	Get components of type TComponent from the entity.
template<typename... TComponent>
decltype(auto)	GetComponents () const
	Get components of type TComponent from the entity.
template<typename TComponent>
decltype(auto)	TryGetComponent ()
	Try to get a component of type TComponent from the entity. It returns a pointer to the component if it exists, or nullptr if it does not exist.
bool	operator== (const Entity &rhs) const
	Equality operator for Entity. It compares the underlying EntityId values to determine if two Entity instances refer to the same entity in the registry.
bool	operator== (const EntityId &rhs) const
	Equality operator for Entity and EntityId. It compares the underlying EntityId value of the Entity with the EntityId to determine if they refer to the same entity in the registry.

Static Public Member Functions
static void	RemoveTemporaryComponents (Core &core)
	Remove all temporary components from the registry.

Private Member Functions
Core &	GetCore () const
	Get a reference to the Core instance that this Entity belongs to. This is used internally to access the registry and other resources when manipulating components.

Private Attributes
std::reference_wrapper< Core >	_core
	A reference to the Core instance that this Entity belongs to.
EntityId	_entityId
	The EntityId that identifies the entity in the Core's registry. This is the underlying identifier for the entity that this Entity class wraps around, and is used for all operations that manipulate the entity in the registry.

Detailed Description

Wrapper class providing a convenient interface for entity manipulation with the Core. Entity acts as a handle to an entity in the registry, combining a Core reference with an EntityId. It provides utility methods to add, remove, and query components, and maintains context relative to the Core it belongs to.

See also

Engine::Core

Engine::EntityId

Constructor & Destructor Documentation

Entity()

Engine::Entity::Entity	(	Core &	core,
		EntityId	entityId )

Create an Entity from EntityId and the Core it belongs to.

Parameters

core	Reference to the Core instance that the Entity belongs to.
entityId	The EntityId that identifies the entity in the Core's registry.

~Entity()

Engine::Entity::~Entity ( )

default

Default destructor for Entity. It does not perform any special cleanup, as the Core is responsible for managing the entity's lifecycle.

Member Function Documentation

AddComponent() [1/2]

template<typename TComponent, typename... TArgs>

decltype(auto) Engine::Entity::AddComponent

(

TArgs &&...

args

)

Add a component to an entity.

Template Parameters

TComponent	The type of the component to add to the registry.
TArgs	The types of the arguments to construct the component in-place in the registry.

Parameters

args	The arguments to construct the component in-place in the registry.

Returns

A reference to the added component.

AddComponent() [2/2]

template<typename TComponent>

decltype(auto) Engine::Entity::AddComponent

(

TComponent &&

component

)

Add a component to an entity.

Template Parameters

TComponent

The type of the component to add to the registry.

Parameters

component

The rvalue of the component to add to the registry.

Returns

A reference to the added component.

Examples

Creating a 2-unit jelly cube with 5x5x5 grid:, Creating a cloth for soft body simulation:, Creating a cube entity:, Creating a cylinder entity:, Creating a plane entity:, Creating a rope for soft body simulation:, and Creating a sphere entity:.

AddComponentIfNotExists()

template<typename TComponent, typename... TArgs>

decltype(auto) Engine::Entity::AddComponentIfNotExists

(

TArgs &&...

args

)

Add a component to an entity if it does not already exist.

Template Parameters

TComponent	type to add to registry.
TArgs	type used to create the component.

Parameters

args	parameters used to instanciate component directly in registry memory.

Returns

reference of the added component.

AddTemporaryComponent()

template<typename TTempComponent, typename... TArgs>

decltype(auto) Engine::Entity::AddTemporaryComponent

(

TArgs &&...

args

)

Add a temporary component to an entity. Temporary component are removed when calling RemoveTemporaryComponents system.

Template Parameters

TTempComponent	type to add to registry
TArgs	type used to create the component

Parameters

args	parameters used to instanciate component directly in registry memory

Returns

reference of the added component

See also

Engine::EntityId::RemoveTemporaryComponents

explicit()

Engine::Entity::explicit

(

false

)

const

Implicit conversion operator to EntityId.

Returns

The EntityId of this Entity.

GetComponents() [1/2]

template<typename... TComponent>

decltype(auto) Engine::Entity::GetComponents

(

)

Get components of type TComponent from the entity.

Template Parameters

TComponent

components to get.

Returns

components of type TComponent from the entity.

GetComponents() [2/2]

template<typename... TComponent>

decltype(auto) Engine::Entity::GetComponents

(

)

const

Get components of type TComponent from the entity.

Template Parameters

TComponent

components to get.

Returns

components of type TComponent from the entity.

GetCore()

Core & Engine::Entity::GetCore ( ) const

private

Get a reference to the Core instance that this Entity belongs to. This is used internally to access the registry and other resources when manipulating components.

Returns

A reference to the Core instance.

HasComponents()

template<typename... TComponent>

bool Engine::Entity::HasComponents

(

)

const

Check if entity have one or multiple component's type.

Template Parameters

TComponent

components to check.

Returns

true if entity have all requested component, false otherwise.

Id()

EntityId Engine::Entity::Id

(

)

const

Get the EntityId associated with this Entity.

Returns

The EntityId of this Entity.

IsAlive()

bool Engine::Entity::IsAlive

(

)

const

Check if the entity is alive.

Returns

true if the entity is alive, false otherwise.

Kill()

void Engine::Entity::Kill

(

)

Kill the entity, removing all components and making it invalid. After calling this method, the EntityId will no longer correspond to a valid entity in the Core's registry, and the Entity will be considered dead.

operator==() [1/2]

bool Engine::Entity::operator==

(

const Entity &

rhs

)

const

Equality operator for Entity. It compares the underlying EntityId values to determine if two Entity instances refer to the same entity in the registry.

Parameters

rhs	The other Entity to compare with.

Returns

true if the entities are equal, false otherwise.

operator==() [2/2]

bool Engine::Entity::operator==

(

const EntityId &

rhs

)

const

Equality operator for Entity and EntityId. It compares the underlying EntityId value of the Entity with the EntityId to determine if they refer to the same entity in the registry.

Parameters

rhs	The EntityId to compare with.

Returns

true if the Entity and EntityId are equal, false otherwise.

RemoveComponent()

template<typename TComponent>

void Engine::Entity::RemoveComponent

(

)

Remove a component from an entity.

Template Parameters

TComponent

The type of the component to remove from the registry.

RemoveTemporaryComponents()

void Engine::Entity::RemoveTemporaryComponents ( Core & core )

static

Remove all temporary components from the registry.

Parameters

core	The Core instance whose registry is used to store the component.

See also

Engine::EntityId::AddTemporaryComponent

TryGetComponent()

template<typename TComponent>

decltype(auto) Engine::Entity::TryGetComponent

(

)

Try to get a component of type TComponent from the entity. It returns a pointer to the component if it exists, or nullptr if it does not exist.

Template Parameters

TComponent

The type of the component to get from the entity.

Returns

The component of type TComponent from the entity if it exists, or nullptr if it does not exist.

Member Data Documentation

_core

std::reference_wrapper<Core> Engine::Entity::_core

private

A reference to the Core instance that this Entity belongs to.

_entityId

EntityId Engine::Entity::_entityId

private

The EntityId that identifies the entity in the Core's registry. This is the underlying identifier for the entity that this Entity class wraps around, and is used for all operations that manipulate the entity in the registry.

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

• src/engine/src/entity/Entity.hpp
• src/engine/src/entity/Entity.cpp
• src/engine/src/entity/Entity.ipp