wEngine::Entity Class Reference

Represents an entity in the ECS (Entity-Component System) architecture. More...

#include <wEntity.hpp>

Inheritance diagram for wEngine::Entity:

Public Member Functions
	Entity ()
virtual	~Entity ()
unsigned int	getEntityID () const
	Returns the unique ID associated with this entity.
void	clearComponents ()
	Removes all components currently attached to the entity.
template<typename T, typename... Args>
std::shared_ptr< T >	addComponent (Args &&... args)
	Adds a new component of type T to the entity.
template<typename T>
void	removeComponent ()
	Removes the component of type T from the entity.
template<typename T>
bool	hasComponent () const noexcept
	Checks whether the entity has a component of type T.
template<typename T>
std::shared_ptr< T >	getComponent () const
	Retrieves the component of type T attached to the entity.
template<typename T>
std::shared_ptr< T >	requireComponent (const std::string &context="") const
	Retrieves the component of type T and throws if it's missing.
template<typename Interface>
std::shared_ptr< Interface >	getInterfaceComponent () const
	Returns the first component that implements the specified interface.

Static Public Member Functions
static void	resetEntityIDCounter ()
	Resets the global entity ID counter to zero.

Detailed Description

Represents an entity in the ECS (Entity-Component System) architecture.

Each entity is uniquely identified and can dynamically manage a collection of components. Components are stored in a type-safe map and accessed by type.

The class provides utility methods to add, remove, retrieve and query components, as well as retrieve components through interfaces.

Note

Entities do not define behavior directly: behavior is defined by the components attached to them.

Author

Wilfried Koch

Copyright

© 2025 Wilfried Koch. All rights reserved.

Constructor & Destructor Documentation

Entity()

wEngine::Entity::Entity

(

)

~Entity()

wEngine::Entity::~Entity ( )

virtual

Member Function Documentation

getEntityID()

unsigned int wEngine::Entity::getEntityID ( ) const

nodiscard

Returns the unique ID associated with this entity.

Returns

Unsigned integer representing the entity's ID.

clearComponents()

void wEngine::Entity::clearComponents

(

)

Removes all components currently attached to the entity.

resetEntityIDCounter()

void wEngine::Entity::resetEntityIDCounter ( )

static

Resets the global entity ID counter to zero.

This affects all subsequently created entities. Use with caution, especially in multi-entity systems.

addComponent()

template<typename T, typename... Args>

std::shared_ptr< T > wEngine::Entity::addComponent ( Args &&... args )

inline

Adds a new component of type T to the entity.

Constructs the component using the provided arguments and attaches it to the entity.

Template Parameters

T	Component type, must inherit from wEngine::Component.
Args	Variadic arguments used to construct the component.

Parameters

args	Constructor arguments forwarded to the component.

Returns

Shared pointer to the newly created component.

Exceptions

std::runtime_error

if a component of the same type already exists in the entity.

removeComponent()

template<typename T>

void wEngine::Entity::removeComponent ( )

inline

Removes the component of type T from the entity.

If no such component exists, this operation does nothing.

Template Parameters

T	Component type to remove.

hasComponent()

template<typename T>

bool wEngine::Entity::hasComponent ( ) const

inlinenodiscardnoexcept

Checks whether the entity has a component of type T.

Template Parameters

T	Component type to check.

Returns

True if the component is present, false otherwise.

getComponent()

template<typename T>

std::shared_ptr< T > wEngine::Entity::getComponent ( ) const

inlinenodiscard

Retrieves the component of type T attached to the entity.

Template Parameters

T	Component type to retrieve.

Returns

Shared pointer to the component if found, or nullptr otherwise.

requireComponent()

template<typename T>

std::shared_ptr< T > wEngine::Entity::requireComponent ( const std::string & context = "" ) const

inlinenodiscard

Retrieves the component of type T and throws if it's missing.

This method is similar to getComponent( ), but throws a std::runtime_error if the component is not found. Useful for critical systems where components must be present.

Template Parameters

T	The type of the component.

Parameters

context

Optional string to specify the context of the call (e.g., method name).

Returns

A shared pointer to the required component.

Exceptions

std::runtime_error

if the component is not found.

getInterfaceComponent()

template<typename Interface>

std::shared_ptr< Interface > wEngine::Entity::getInterfaceComponent ( ) const

inlinenodiscard

Returns the first component that implements the specified interface.

Checks all components attached to the entity using dynamic casting. If a component matches the given interface type, it is returned.

Template Parameters

Interface

The desired interface type.

Returns

A shared pointer to the matching component, or nullptr if none found.

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

• wEntity.hpp
• wEntity.cpp