Fast and reliable entity-component system. More...

#include <entt.hpp>

Public Types
using	entity_type = Entity
	Underlying entity identifier.

using	version_type = typename traits_type::version_type
	Underlying version type.

using	size_type = std::size_t
	Unsigned integer type.

using	poly_storage = typename poly_storage_traits< Entity >::storage_type
	Poly storage type.

Public Member Functions
	basic_registry ()=default
	Default constructor.

	basic_registry (basic_registry &&)=default
	Default move constructor.

basic_registry &	operator= (basic_registry &&)=default
	Default move assignment operator. More...

template<typename Component >
void	prepare ()
	Prepares a pool for the given type if required. More...

poly_storage	storage (const type_info info)
	Returns a poly storage for a given type. More...

poly_storage	storage (const type_info info) const
	Returns a poly storage for a given type. More...

template<typename Component >
size_type	size () const
	Returns the number of existing components of the given type. More...

size_type	size () const ENTT_NOEXCEPT
	Returns the number of entities created so far. More...

size_type	alive () const
	Returns the number of entities still in use. More...

template<typename... Component>
void	reserve (const size_type cap)
	Increases the capacity of the registry or of the pools for the given components. More...

void	reserve_pools (const size_t count)
	Reserves enough space to store `count` pools. More...

template<typename Component >
size_type	capacity () const
	Returns the capacity of the pool for the given component. More...

size_type	capacity () const ENTT_NOEXCEPT
	Returns the number of entities that a registry has currently allocated space for. More...

template<typename... Component>
void	shrink_to_fit ()
	Requests the removal of unused capacity for the given components. More...

template<typename... Component>
bool	empty () const
	Checks whether the registry or the pools of the given components are empty. More...

template<typename Component >
const Component *	raw () const
	Direct access to the list of components of a given pool. More...

template<typename Component >
Component *	raw ()
	Direct access to the list of components of a given pool. More...

template<typename Component >
const entity_type *	data () const
	Direct access to the list of entities of a given pool. More...

const entity_type *	data () const ENTT_NOEXCEPT
	Direct access to the list of entities of a registry. More...

entity_type	destroyed () const ENTT_NOEXCEPT
	Returns the head of the list of destroyed entities. More...

bool	valid (const entity_type entity) const
	Checks if an entity identifier refers to a valid entity. More...

version_type	current (const entity_type entity) const
	Returns the actual version for an entity identifier. More...

entity_type	create ()
	Creates a new entity and returns it. More...

entity_type	create (const entity_type hint)
	Creates a new entity and returns it. More...

template<typename It >
void	create (It first, It last)
	Assigns each element in a range an entity. More...

template<typename It >
void	assign (It first, It last, const entity_type destroyed)
	Assigns entities to an empty registry. More...

void	destroy (const entity_type entity)
	Destroys an entity. More...

void	destroy (const entity_type entity, const version_type version)
	Destroys an entity. More...

template<typename It >
void	destroy (It first, It last)
	Destroys all the entities in a range. More...

template<typename Component , typename... Args>
decltype(auto)	emplace (const entity_type entity, Args &&... args)
	Assigns the given component to an entity. More...

template<typename Component , typename It >
void	insert (It first, It last, const Component &value={})
	Assigns each entity in a range the given component. More...

template<typename Component , typename EIt , typename CIt >
void	insert (EIt first, EIt last, CIt from, CIt to)
	Assigns each entity in a range the given components. More...

template<typename Component , typename... Args>
decltype(auto)	emplace_or_replace (const entity_type entity, Args &&... args)
	Assigns or replaces the given component for an entity. More...

template<typename Component , typename... Func>
decltype(auto)	patch (const entity_type entity, Func &&... func)
	Patches the given component for an entity. More...

template<typename Component , typename... Args>
decltype(auto)	replace (const entity_type entity, Args &&... args)
	Replaces the given component for an entity. More...

template<typename... Component>
void	remove (const entity_type entity)
	Removes the given components from an entity. More...

template<typename... Component, typename It >
void	remove (It first, It last)
	Removes the given components from all the entities in a range. More...

template<typename... Component>
size_type	remove_if_exists (const entity_type entity)
	Removes the given components from an entity. More...

void	remove_all (const entity_type entity)
	Removes all the components from an entity and makes it orphaned. More...

template<typename... Component>
bool	has (const entity_type entity) const
	Checks if an entity has all the given components. More...

template<typename... Component>
bool	any (const entity_type entity) const
	Checks if an entity has at least one of the given components. More...

template<typename... Component>
decltype(auto)	get ([[maybe_unused]] const entity_type entity) const
	Returns references to the given components for an entity. More...

template<typename... Component>
decltype(auto)	get ([[maybe_unused]] const entity_type entity)
	Returns references to the given components for an entity. More...

template<typename Component , typename... Args>
decltype(auto)	get_or_emplace (const entity_type entity, Args &&... args)
	Returns a reference to the given component for an entity. More...

template<typename... Component>
auto	try_get ([[maybe_unused]] const entity_type entity) const
	Returns pointers to the given components for an entity. More...

template<typename... Component>
auto	try_get ([[maybe_unused]] const entity_type entity)
	Returns pointers to the given components for an entity. More...

template<typename... Component>
void	clear ()
	Clears a whole registry or the pools for the given components. More...

template<typename Func >
void	each (Func func) const
	Iterates all the entities that are still in use. More...

bool	orphan (const entity_type entity) const
	Checks if an entity has components assigned. More...

template<typename Func >
void	orphans (Func func) const
	Iterates orphans and applies them the given function object. More...

template<typename Component >
auto	on_construct ()
	Returns a sink object for the given component. More...

template<typename Component >
auto	on_update ()
	Returns a sink object for the given component. More...

template<typename Component >
auto	on_destroy ()
	Returns a sink object for the given component. More...

template<typename... Component, typename... Exclude>
basic_view< Entity, exclude_t< Exclude... >, Component... >	view (exclude_t< Exclude... >={}) const
	Returns a view for the given components. More...

template<typename... Component, typename... Exclude>
basic_view< Entity, exclude_t< Exclude... >, Component... >	view (exclude_t< Exclude... >={})
	Returns a view for the given components. More...

template<typename ItComp , typename ItExcl = id_type *>
basic_runtime_view< Entity >	runtime_view (ItComp first, ItComp last, ItExcl from={}, ItExcl to={}) const
	Returns a runtime view for the given components. More...

template<typename... Owned, typename... Get, typename... Exclude>
basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >	group (get_t< Get... >, exclude_t< Exclude... >={})
	Returns a group for the given components. More...

template<typename... Owned, typename... Get, typename... Exclude>
basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >	group_if_exists (get_t< Get... >, exclude_t< Exclude... >={}) const
	Returns a group for the given components. More...

template<typename... Owned, typename... Exclude>
basic_group< Entity, exclude_t< Exclude... >, get_t<>, Owned... >	group (exclude_t< Exclude... >={})
	Returns a group for the given components. More...

template<typename... Owned, typename... Exclude>
basic_group< Entity, exclude_t< Exclude... >, get_t<>, Owned... >	group_if_exists (exclude_t< Exclude... >={}) const
	Returns a group for the given components. More...

template<typename... Component>
bool	sortable () const
	Checks whether the given components belong to any group. More...

template<typename... Owned, typename... Get, typename... Exclude>
bool	sortable (const basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... > &) ENTT_NOEXCEPT
	Checks whether a group can be sorted. More...

template<typename Component , typename Compare , typename Sort = std_sort, typename... Args>
void	sort (Compare compare, Sort algo=Sort{}, Args &&... args)
	Sorts the pool of entities for the given component. More...

template<typename To , typename From >
void	sort ()
	Sorts two pools of components in the same way. More...

template<typename Func >
void	visit (entity_type entity, Func func) const
	Visits an entity and returns the type info for its components. More...

template<typename Func >
void	visit (Func func) const
	Visits a registry and returns the type info for its components. More...

template<typename Type , typename... Args>
Type &	set (Args &&... args)
	Binds an object to the context of the registry. More...

template<typename Type >
void	unset ()
	Unsets a context variable if it exists. More...

template<typename Type , typename... Args>
Type &	ctx_or_set (Args &&... args)
	Binds an object to the context of the registry. More...

template<typename Type >
const Type *	try_ctx () const
	Returns a pointer to an object in the context of the registry. More...

template<typename Type >
Type *	try_ctx ()
	Returns a pointer to an object in the context of the registry. More...

template<typename Type >
const Type &	ctx () const
	Returns a reference to an object in the context of the registry. More...

template<typename Type >
Type &	ctx ()
	Returns a reference to an object in the context of the registry. More...

template<typename Func >
void	ctx (Func func) const
	Visits a registry and returns the type info for its context variables. More...

Static Public Member Functions
static entity_type	entity (const entity_type entity) ENTT_NOEXCEPT
	Returns the entity identifier without the version. More...

static version_type	version (const entity_type entity) ENTT_NOEXCEPT
	Returns the version stored along with an entity identifier. More...

Detailed Description

template<typename Entity>
class entt::basic_registry< Entity >

Fast and reliable entity-component system.

The registry is the core class of the entity-component framework.
It stores entities and arranges pools of components on a per request basis. By means of a registry, users can manage entities and components, then create views or groups to iterate them.

Template Parameters

Entity A valid entity type (see entt_traits for more details).

Member Function Documentation

◆ alive()

template<typename Entity>

size_type entt::basic_registry< Entity >::alive ( ) const

inline

Returns the number of entities still in use.

Returns: Number of entities still in use.

◆ any()

template<typename Entity>

template<typename... Component>

bool entt::basic_registry< Entity >::any ( const entity_type entity ) const

inline

Checks if an entity has at least one of the given components.

Warning: Attempting to use an invalid entity results in undefined behavior.

Template Parameters

Component Components for which to perform the check.

Parameters

entity A valid entity identifier.

Returns: True if the entity has at least one of the given components, false otherwise.

◆ assign()

template<typename Entity>

template<typename It >

void entt::basic_registry< Entity >::assign	(	It	first,
		It	last,
		const entity_type	destroyed
	)

inline

Assigns entities to an empty registry.

This function is intended for use in conjunction with raw and assign.
Don't try to inject ranges of randomly generated entities nor the wrong head for the list of destroyed entities. There is no guarantee that a registry will continue to work properly in this case.

Warning: All pools must be empty for this to work properly.

Template Parameters

It	Type of input iterator.

Parameters

first	An iterator to the first element of the range of entities.
last	An iterator past the last element of the range of entities.
destroyed	The head of the list of destroyed entities.

◆ capacity() [1/2]

template<typename Entity>

template<typename Component >

size_type entt::basic_registry< Entity >::capacity ( ) const

inline

Returns the capacity of the pool for the given component.

Template Parameters

Component Type of component in which one is interested.

Returns: Capacity of the pool of the given component.

◆ capacity() [2/2]

template<typename Entity>

size_type entt::basic_registry< Entity >::capacity ( ) const

inline

Returns the number of entities that a registry has currently allocated space for.

Returns: Capacity of the registry.

◆ clear()

template<typename Entity>

template<typename... Component>

void entt::basic_registry< Entity >::clear ( )

inline

Clears a whole registry or the pools for the given components.

Template Parameters

Component Types of components to remove from their entities.

◆ create() [1/3]

template<typename Entity>

entity_type entt::basic_registry< Entity >::create ( )

inline

Creates a new entity and returns it.

There are two kinds of possible entity identifiers:

Newly created ones in case no entities have been previously destroyed.
Recycled ones with updated versions.

Returns: A valid entity identifier.

◆ create() [2/3]

template<typename Entity>

entity_type entt::basic_registry< Entity >::create ( const entity_type hint )

inline

Creates a new entity and returns it.

See also: create

If the requested entity isn't in use, the suggested identifier is created and returned. Otherwise, a new one will be generated for this purpose.

Parameters

hint	A desired entity identifier.

Returns: A valid entity identifier.

◆ create() [3/3]

template<typename Entity>

template<typename It >

void entt::basic_registry< Entity >::create	(	It	first,
		It	last
	)

inline

Assigns each element in a range an entity.

See also: create

Template Parameters

It	Type of forward iterator.

Parameters

first	An iterator to the first element of the range to generate.
last	An iterator past the last element of the range to generate.

◆ ctx() [1/3]

template<typename Entity>

template<typename Type >

const Type& entt::basic_registry< Entity >::ctx ( ) const

inline

Returns a reference to an object in the context of the registry.

Warning: Attempting to get a context variable that doesn't exist results in undefined behavior.

Template Parameters

Type	Type of object to get.

Returns: A valid reference to the object in the context of the registry.

◆ ctx() [2/3]

template<typename Entity>

template<typename Type >

Type& entt::basic_registry< Entity >::ctx ( )

inline

Returns a reference to an object in the context of the registry.

Warning: Attempting to get a context variable that doesn't exist results in undefined behavior.

Template Parameters

Type	Type of object to get.

Returns: A valid reference to the object in the context of the registry.

◆ ctx() [3/3]

template<typename Entity>

template<typename Func >

void entt::basic_registry< Entity >::ctx ( Func func ) const

inline

Visits a registry and returns the type info for its context variables.

The signature of the function should be equivalent to the following:

void(const type_info);

Returned identifiers are those of the context variables currently set.

See also: type_info

Warning: It's not specified whether a context variable created during the visit is returned or not to the caller.

Template Parameters

Func	Type of the function object to invoke.

Parameters

func	A valid function object.

◆ ctx_or_set()

template<typename Entity>

template<typename Type , typename... Args>

Type& entt::basic_registry< Entity >::ctx_or_set ( Args &&... args )

inline

Binds an object to the context of the registry.

In case the context doesn't contain the given object, the parameters provided are used to construct it.

Template Parameters

Type	Type of object to set.
Args	Types of arguments to use to construct the object.

Parameters

args	Parameters to use to initialize the object.

Returns: A reference to the object in the context of the registry.

◆ current()

template<typename Entity>

version_type entt::basic_registry< Entity >::current ( const entity_type entity ) const

inline

Returns the actual version for an entity identifier.

Warning: Attempting to use an entity that doesn't belong to the registry results in undefined behavior. An entity belongs to the registry even if it has been previously destroyed and/or recycled.

Parameters

entity A valid entity identifier.

Returns: Actual version for the given entity identifier.

◆ data() [1/2]

template<typename Entity>

template<typename Component >

const entity_type* entt::basic_registry< Entity >::data ( ) const

inline

Direct access to the list of entities of a given pool.

The returned pointer is such that range [data<Component>(), data<Component>() + size<Component>()) is always a valid range, even if the container is empty.

Entities are in the reverse order as imposed by the sorting functionalities.

Template Parameters

Component Type of component in which one is interested.

Returns: A pointer to the array of entities.

◆ data() [2/2]

template<typename Entity>

const entity_type* entt::basic_registry< Entity >::data ( ) const

inline

Direct access to the list of entities of a registry.

The returned pointer is such that range [data(), data() + size()) is always a valid range, even if the container is empty.

Warning: This list contains both valid and destroyed entities and isn't suitable for direct use.

Returns: A pointer to the array of entities.

◆ destroy() [1/3]

template<typename Entity>

void entt::basic_registry< Entity >::destroy ( const entity_type entity )

inline

Destroys an entity.

When an entity is destroyed, its version is updated and the identifier can be recycled at any time.

See also: remove_all

Parameters

entity A valid entity identifier.

◆ destroy() [2/3]

template<typename Entity>

void entt::basic_registry< Entity >::destroy	(	const entity_type	entity,
		const version_type	version
	)

inline

Destroys an entity.

If the entity isn't already destroyed, the suggested version is used instead of the implicitly generated one.

See also: remove_all

Parameters

entity	A valid entity identifier.
version	A desired version upon destruction.

◆ destroy() [3/3]

template<typename Entity>

template<typename It >

void entt::basic_registry< Entity >::destroy	(	It	first,
		It	last
	)

inline

Destroys all the entities in a range.

See also: destroy

Template Parameters

It	Type of input iterator.

Parameters

first	An iterator to the first element of the range of entities.
last	An iterator past the last element of the range of entities.

◆ destroyed()

template<typename Entity>

entity_type entt::basic_registry< Entity >::destroyed ( ) const

inline

Returns the head of the list of destroyed entities.

This function is intended for use in conjunction with assign.
The returned entity has an invalid identifier in all cases.

Returns: The head of the list of destroyed entities.

◆ each()

template<typename Entity>

template<typename Func >

void entt::basic_registry< Entity >::each ( Func func ) const

inline

Iterates all the entities that are still in use.

The function object is invoked for each entity that is still in use.
The signature of the function should be equivalent to the following:

void(const Entity);

This function is fairly slow and should not be used frequently. However, it's useful for iterating all the entities still in use, regardless of their components.

Template Parameters

Func	Type of the function object to invoke.

Parameters

func	A valid function object.

◆ emplace()

template<typename Entity>

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry< Entity >::emplace	(	const entity_type	entity,
		Args &&...	args
	)

inline

Assigns the given component to an entity.

A new instance of the given component is created and initialized with the arguments provided (the component must have a proper constructor or be of aggregate type). Then the component is assigned to the given entity.

Warning: Attempting to use an invalid entity or to assign a component to an entity that already owns it results in undefined behavior.

Template Parameters

Component	Type of component to create.
Args	Types of arguments to use to construct the component.

Parameters

entity	A valid entity identifier.
args	Parameters to use to initialize the component.

Returns: A reference to the newly created component.

◆ emplace_or_replace()

template<typename Entity>

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry< Entity >::emplace_or_replace	(	const entity_type	entity,
		Args &&...	args
	)

inline

Assigns or replaces the given component for an entity.

Equivalent to the following snippet (pseudocode):

auto &component = registry.has<Component>(entity) ? registry.replace<Component>(entity, args...) : registry.emplace<Component>(entity, args...);

Prefer this function anyway because it has slightly better performance.

Warning: Attempting to use an invalid entity results in undefined behavior.

Template Parameters

Component	Type of component to assign or replace.
Args	Types of arguments to use to construct the component.

Parameters

entity	A valid entity identifier.
args	Parameters to use to initialize the component.

Returns: A reference to the newly created component.

◆ empty()

template<typename Entity>

template<typename... Component>

bool entt::basic_registry< Entity >::empty ( ) const

inline

Checks whether the registry or the pools of the given components are empty.

A registry is considered empty when it doesn't contain entities that are still in use.

Template Parameters

Component Types of components in which one is interested.

Returns: True if the registry or the pools of the given components are empty, false otherwise.

◆ entity()

template<typename Entity>

static entity_type entt::basic_registry< Entity >::entity ( const entity_type entity )

inlinestatic

Returns the entity identifier without the version.

Parameters

entity An entity identifier, either valid or not.

Returns: The entity identifier without the version.

◆ get() [1/2]

template<typename Entity>

template<typename... Component>

decltype(auto) entt::basic_registry< Entity >::get ( [[maybe_unused] ] const entity_type entity ) const

inline

Returns references to the given components for an entity.

Warning: Attempting to use an invalid entity or to get a component from an entity that doesn't own it results in undefined behavior.

Template Parameters

Component Types of components to get.

Parameters

entity A valid entity identifier.

Returns: References to the components owned by the entity.

◆ get() [2/2]

template<typename Entity>

template<typename... Component>

decltype(auto) entt::basic_registry< Entity >::get ( [[maybe_unused] ] const entity_type entity )

inline

Returns references to the given components for an entity.

Warning: Attempting to use an invalid entity or to get a component from an entity that doesn't own it results in undefined behavior.

Template Parameters

Component Types of components to get.

Parameters

entity A valid entity identifier.

Returns: References to the components owned by the entity.

◆ get_or_emplace()

template<typename Entity>

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry< Entity >::get_or_emplace	(	const entity_type	entity,
		Args &&...	args
	)

inline

Returns a reference to the given component for an entity.

In case the entity doesn't own the component, the parameters provided are used to construct it.
Equivalent to the following snippet (pseudocode):

auto &component = registry.has<Component>(entity) ? registry.get<Component>(entity) : registry.emplace<Component>(entity, args...);

Prefer this function anyway because it has slightly better performance.

Warning: Attempting to use an invalid entity results in undefined behavior.

Template Parameters

Component	Type of component to get.
Args	Types of arguments to use to construct the component.

Parameters

entity	A valid entity identifier.
args	Parameters to use to initialize the component.

Returns: Reference to the component owned by the entity.

◆ group() [1/2]

template<typename Entity>

template<typename... Owned, typename... Get, typename... Exclude>

basic_group<Entity, exclude_t<Exclude...>, get_t<Get...>, Owned...> entt::basic_registry< Entity >::group	(	get_t< Get... >	,
		exclude_t< Exclude... >	= `{}`
	)

inline

Returns a group for the given components.

This kind of objects are created on the fly and share with the registry its internal data structures.
Feel free to discard a group after the use. Creating and destroying a group is an incredibly cheap operation because they do not require any type of initialization, but for the first time they are requested.
As a rule of thumb, storing a group should never be an option.

Groups support exclusion lists and can own types of components. The more types are owned by a group, the faster it is to iterate entities and components.
However, groups also affect some features of the registry such as the creation and destruction of components, which will consequently be slightly slower (nothing that can be noticed in most cases).

Note: Pools of components that are owned by a group cannot be sorted anymore. The group takes the ownership of the pools and arrange components so as to iterate them as fast as possible.

Template Parameters

Owned	Types of components owned by the group.
Get	Types of components observed by the group.
Exclude	Types of components used to filter the group.

Returns: A newly created group.

◆ group() [2/2]

template<typename Entity>

template<typename... Owned, typename... Exclude>

basic_group<Entity, exclude_t<Exclude...>, get_t<>, Owned...> entt::basic_registry< Entity >::group ( exclude_t< Exclude... > = {} )

inline

Returns a group for the given components.

See also: group

Template Parameters

Owned	Types of components owned by the group.
Exclude	Types of components used to filter the group.

Returns: A newly created group.

◆ group_if_exists() [1/2]

template<typename Entity>

template<typename... Owned, typename... Get, typename... Exclude>

basic_group<Entity, exclude_t<Exclude...>, get_t<Get...>, Owned...> entt::basic_registry< Entity >::group_if_exists	(	get_t< Get... >	,
		exclude_t< Exclude... >	= `{}`
	)		const

inline

Returns a group for the given components.

See also: group

Template Parameters

Owned	Types of components owned by the group.
Get	Types of components observed by the group.
Exclude	Types of components used to filter the group.

Returns: A newly created group.

◆ group_if_exists() [2/2]

template<typename Entity>

template<typename... Owned, typename... Exclude>

basic_group<Entity, exclude_t<Exclude...>, get_t<>, Owned...> entt::basic_registry< Entity >::group_if_exists ( exclude_t< Exclude... > = {} ) const

inline

Returns a group for the given components.

See also: group_if_exists

Template Parameters

Owned	Types of components owned by the group.
Exclude	Types of components used to filter the group.

Returns: A newly created group.

◆ has()

template<typename Entity>

template<typename... Component>

bool entt::basic_registry< Entity >::has ( const entity_type entity ) const

inline

Checks if an entity has all the given components.

Warning: Attempting to use an invalid entity results in undefined behavior.

Template Parameters

Component Components for which to perform the check.

Parameters

entity A valid entity identifier.

Returns: True if the entity has all the components, false otherwise.

◆ insert() [1/2]

template<typename Entity>

template<typename Component , typename It >

void entt::basic_registry< Entity >::insert	(	It	first,
		It	last,
		const Component &	value = `{}`
	)

inline

Assigns each entity in a range the given component.

See also: emplace

Template Parameters

Component	Type of component to create.
It	Type of input iterator.

Parameters

first	An iterator to the first element of the range of entities.
last	An iterator past the last element of the range of entities.
value	An instance of the component to assign.

◆ insert() [2/2]

template<typename Entity>

template<typename Component , typename EIt , typename CIt >

void entt::basic_registry< Entity >::insert	(	EIt	first,
		EIt	last,
		CIt	from,
		CIt	to
	)

inline

Assigns each entity in a range the given components.

See also: emplace

Template Parameters

Component	Type of component to create.
EIt	Type of input iterator.
CIt	Type of input iterator.

Parameters

first	An iterator to the first element of the range of entities.
last	An iterator past the last element of the range of entities.
from	An iterator to the first element of the range of components.
to	An iterator past the last element of the range of components.

◆ on_construct()

template<typename Entity>

template<typename Component >

auto entt::basic_registry< Entity >::on_construct ( )

inline

Returns a sink object for the given component.

The sink returned by this function can be used to receive notifications whenever a new instance of the given component is created and assigned to an entity.
The function type for a listener is equivalent to:

void(basic_registry<Entity> &, Entity);

Listeners are invoked after the component has been assigned to the entity.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ on_destroy()

template<typename Entity>

template<typename Component >

auto entt::basic_registry< Entity >::on_destroy ( )

inline

Returns a sink object for the given component.

The sink returned by this function can be used to receive notifications whenever an instance of the given component is removed from an entity and thus destroyed.
The function type for a listener is equivalent to:

void(basic_registry<Entity> &, Entity);

Listeners are invoked before the component has been removed from the entity.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ on_update()

template<typename Entity>

template<typename Component >

auto entt::basic_registry< Entity >::on_update ( )

inline

Returns a sink object for the given component.

The sink returned by this function can be used to receive notifications whenever an instance of the given component is explicitly updated.
The function type for a listener is equivalent to:

void(basic_registry<Entity> &, Entity);

Listeners are invoked after the component has been updated.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ operator=()

template<typename Entity>

basic_registry& entt::basic_registry< Entity >::operator= ( basic_registry< Entity > && )

default

Default move assignment operator.

Returns: This registry.

◆ orphan()

template<typename Entity>

bool entt::basic_registry< Entity >::orphan ( const entity_type entity ) const

inline

Checks if an entity has components assigned.

Parameters

entity A valid entity identifier.

Returns: True if the entity has no components assigned, false otherwise.

◆ orphans()

template<typename Entity>

template<typename Func >

void entt::basic_registry< Entity >::orphans ( Func func ) const

inline

Iterates orphans and applies them the given function object.

The function object is invoked for each entity that is still in use and has no components assigned.
The signature of the function should be equivalent to the following:

void(const Entity);

This function can be very slow and should not be used frequently.

Template Parameters

Func	Type of the function object to invoke.

Parameters

func	A valid function object.

◆ patch()

template<typename Entity>

template<typename Component , typename... Func>

decltype(auto) entt::basic_registry< Entity >::patch	(	const entity_type	entity,
		Func &&...	func
	)

inline

Patches the given component for an entity.

The signature of the functions should be equivalent to the following:

void(Component &);

Note: Empty types aren't explicitly instantiated and therefore they are never returned. However, this function can be used to trigger an update signal for them.

Warning: Attempting to use an invalid entity or to patch a component of an entity that doesn't own it results in undefined behavior.

Template Parameters

Component	Type of component to patch.
Func	Types of the function objects to invoke.

Parameters

entity	A valid entity identifier.
func	Valid function objects.

Returns: A reference to the patched component.

◆ prepare()

template<typename Entity>

template<typename Component >

void entt::basic_registry< Entity >::prepare ( )

inline

Prepares a pool for the given type if required.

Template Parameters

Component Type of component for which to prepare a pool.

◆ raw() [1/2]

template<typename Entity>

template<typename Component >

const Component* entt::basic_registry< Entity >::raw ( ) const

inline

Direct access to the list of components of a given pool.

The returned pointer is such that range [raw<Component>(), raw<Component>() + size<Component>()) is always a valid range, even if the container is empty.

Components are in the reverse order as imposed by the sorting functionalities.

Note: Empty components aren't explicitly instantiated. Therefore, this function isn't available for them. A compilation error will occur if invoked.

Template Parameters

Component Type of component in which one is interested.

Returns: A pointer to the array of components of the given type.

◆ raw() [2/2]

template<typename Entity>

template<typename Component >

Component* entt::basic_registry< Entity >::raw ( )

inline

Direct access to the list of components of a given pool.

The returned pointer is such that range [raw<Component>(), raw<Component>() + size<Component>()) is always a valid range, even if the container is empty.

Components are in the reverse order as imposed by the sorting functionalities.

Note: Empty components aren't explicitly instantiated. Therefore, this function isn't available for them. A compilation error will occur if invoked.

Template Parameters

Component Type of component in which one is interested.

Returns: A pointer to the array of components of the given type.

◆ remove() [1/2]

template<typename Entity>

template<typename... Component>

void entt::basic_registry< Entity >::remove ( const entity_type entity )

inline

Removes the given components from an entity.

Warning: Attempting to use an invalid entity or to remove a component from an entity that doesn't own it results in undefined behavior.

Template Parameters

Component Types of components to remove.

Parameters

entity A valid entity identifier.

◆ remove() [2/2]

template<typename Entity>

template<typename... Component, typename It >

void entt::basic_registry< Entity >::remove	(	It	first,
		It	last
	)

inline

Removes the given components from all the entities in a range.

See also: remove

Template Parameters

Component	Types of components to remove.
It	Type of input iterator.

Parameters

first	An iterator to the first element of the range of entities.
last	An iterator past the last element of the range of entities.

◆ remove_all()

template<typename Entity>

void entt::basic_registry< Entity >::remove_all ( const entity_type entity )

inline

Removes all the components from an entity and makes it orphaned.

Warning: In case there are listeners that observe the destruction of components and assign other components to the entity in their bodies, the result of invoking this function may not be as expected. In the worst case, it could lead to undefined behavior.; Attempting to use an invalid entity results in undefined behavior.

Parameters

entity A valid entity identifier.

◆ remove_if_exists()

template<typename Entity>

template<typename... Component>

size_type entt::basic_registry< Entity >::remove_if_exists ( const entity_type entity )

inline

Removes the given components from an entity.

Equivalent to the following snippet (pseudocode):

if(registry.has<Component>(entity)) { registry.remove<Component>(entity) }

Prefer this function anyway because it has slightly better performance.

Warning: Attempting to use an invalid entity results in undefined behavior.

Template Parameters

Component Types of components to remove.

Parameters

entity A valid entity identifier.

Returns: The number of components actually removed.

◆ replace()

template<typename Entity>

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry< Entity >::replace	(	const entity_type	entity,
		Args &&...	args
	)

inline

Replaces the given component for an entity.

A new instance of the given component is created and initialized with the arguments provided (the component must have a proper constructor or be of aggregate type). Then the component is assigned to the given entity.

Warning: Attempting to use an invalid entity or to replace a component of an entity that doesn't own it results in undefined behavior.

Template Parameters

Component	Type of component to replace.
Args	Types of arguments to use to construct the component.

Parameters

entity	A valid entity identifier.
args	Parameters to use to initialize the component.

Returns: A reference to the component being replaced.

◆ reserve()

template<typename Entity>

template<typename... Component>

void entt::basic_registry< Entity >::reserve ( const size_type cap )

inline

Increases the capacity of the registry or of the pools for the given components.

If no components are specified, the capacity of the registry is increased, that is the number of entities it contains. Otherwise the capacity of the pools for the given components is increased.
In both cases, if the new capacity is greater than the current capacity, new storage is allocated, otherwise the method does nothing.

Template Parameters

Component Types of components for which to reserve storage.

Parameters

cap	Desired capacity.

◆ reserve_pools()

template<typename Entity>

void entt::basic_registry< Entity >::reserve_pools ( const size_t count )

inline

Reserves enough space to store count pools.

Parameters

count Number of pools to reserve space for.

◆ runtime_view()

template<typename Entity>

template<typename ItComp , typename ItExcl = id_type *>

basic_runtime_view<Entity> entt::basic_registry< Entity >::runtime_view	(	ItComp	first,
		ItComp	last,
		ItExcl	from = `{}`,
		ItExcl	to = `{}`
	)		const

inline

Returns a runtime view for the given components.

This kind of objects are created on the fly and share with the registry its internal data structures.
Users should throw away the view after use. Fortunately, creating and destroying a runtime view is an incredibly cheap operation because they do not require any type of initialization.
As a rule of thumb, storing a view should never be an option.

Runtime views are to be used when users want to construct a view from some external inputs and don't know at compile-time what are the required components.

Template Parameters

ItComp	Type of input iterator for the components to use to construct the view.
ItExcl	Type of input iterator for the components to use to filter the view.

Parameters

first	An iterator to the first element of the range of components to use to construct the view.
last	An iterator past the last element of the range of components to use to construct the view.
from	An iterator to the first element of the range of components to use to filter the view.
to	An iterator past the last element of the range of components to use to filter the view.

Returns: A newly created runtime view.

◆ set()

template<typename Entity>

template<typename Type , typename... Args>

Type& entt::basic_registry< Entity >::set ( Args &&... args )

inline

Binds an object to the context of the registry.

If the value already exists it is overwritten, otherwise a new instance of the given type is created and initialized with the arguments provided.

Template Parameters

Type	Type of object to set.
Args	Types of arguments to use to construct the object.

Parameters

args	Parameters to use to initialize the value.

Returns: A reference to the newly created object.

◆ shrink_to_fit()

template<typename Entity>

template<typename... Component>

void entt::basic_registry< Entity >::shrink_to_fit ( )

inline

Requests the removal of unused capacity for the given components.

Template Parameters

Component Types of components for which to reclaim unused capacity.

◆ size() [1/2]

template<typename Entity>

template<typename Component >

size_type entt::basic_registry< Entity >::size ( ) const

inline

Returns the number of existing components of the given type.

Template Parameters

Component Type of component of which to return the size.

Returns: Number of existing components of the given type.

◆ size() [2/2]

template<typename Entity>

size_type entt::basic_registry< Entity >::size ( ) const

inline

Returns the number of entities created so far.

Returns: Number of entities created so far.

◆ sort() [1/2]

template<typename Entity>

template<typename Component , typename Compare , typename Sort = std_sort, typename... Args>

void entt::basic_registry< Entity >::sort	(	Compare	compare,
		Sort	algo = `Sort{}`,
		Args &&...	args
	)

inline

Sorts the pool of entities for the given component.

The order of the elements in a pool is highly affected by assignments of components to entities and deletions. Components are arranged to maximize the performance during iterations and users should not make any assumption on the order.
This function can be used to impose an order to the elements in the pool of the given component. The order is kept valid until a component of the given type is assigned or removed from an entity.

The comparison function object must return true if the first element is less than the second one, false otherwise. The signature of the comparison function should be equivalent to one of the following:

bool(const Entity, const Entity);

bool(const Component &, const Component &);

Moreover, the comparison function object shall induce a strict weak ordering on the values.

The sort function oject must offer a member function template operator() that accepts three arguments:

An iterator to the first element of the range to sort.
An iterator past the last element of the range to sort.
A comparison function to use to compare the elements.

The comparison funtion object received by the sort function object hasn't necessarily the type of the one passed along with the other parameters to this member function.

Warning: Pools of components owned by a group cannot be sorted.

Template Parameters

Component	Type of components to sort.
Compare	Type of comparison function object.
Sort	Type of sort function object.
Args	Types of arguments to forward to the sort function object.

Parameters

compare	A valid comparison function object.
algo	A valid sort function object.
args	Arguments to forward to the sort function object, if any.

◆ sort() [2/2]

template<typename Entity>

template<typename To , typename From >

void entt::basic_registry< Entity >::sort ( )

inline

Sorts two pools of components in the same way.

The order of the elements in a pool is highly affected by assignments of components to entities and deletions. Components are arranged to maximize the performance during iterations and users should not make any assumption on the order.

It happens that different pools of components must be sorted the same way because of runtime and/or performance constraints. This function can be used to order a pool of components according to the order between the entities in another pool of components.

How it works

Being A and B the two sets where B is the master (the one the order of which rules) and A is the slave (the one to sort), after a call to this function an iterator for A will return the entities according to the following rules:

All the entities in A that are also in B are returned first according to the order they have in B.
All the entities in A that are not in B are returned in no particular order after all the other entities.

Any subsequent change to B won't affect the order in A.

Warning: Pools of components owned by a group cannot be sorted.

Template Parameters

To	Type of components to sort.
From	Type of components to use to sort.

◆ sortable() [1/2]

template<typename Entity>

template<typename... Component>

bool entt::basic_registry< Entity >::sortable ( ) const

inline

Checks whether the given components belong to any group.

Template Parameters

Component Types of components in which one is interested.

Returns: True if the pools of the given components are sortable, false otherwise.

◆ sortable() [2/2]

template<typename Entity>

template<typename... Owned, typename... Get, typename... Exclude>

bool entt::basic_registry< Entity >::sortable ( const basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... > & )

inline

Checks whether a group can be sorted.

Template Parameters

Owned	Types of components owned by the group.
Get	Types of components observed by the group.
Exclude	Types of components used to filter the group.

Returns: True if the group can be sorted, false otherwise.

◆ storage() [1/2]

template<typename Entity>

poly_storage entt::basic_registry< Entity >::storage ( const type_info info )

inline

Returns a poly storage for a given type.

Parameters

info	The type for which to return a poly storage.

Returns: A valid poly storage if a pool for the given type exists, an empty and thus invalid element otherwise.

◆ storage() [2/2]

template<typename Entity>

poly_storage entt::basic_registry< Entity >::storage ( const type_info info ) const

inline

Returns a poly storage for a given type.

Parameters

info	The type for which to return a poly storage.

Returns: A valid poly storage if a pool for the given type exists, an empty and thus invalid element otherwise.

◆ try_ctx() [1/2]

template<typename Entity>

template<typename Type >

const Type* entt::basic_registry< Entity >::try_ctx ( ) const

inline

Returns a pointer to an object in the context of the registry.

Template Parameters

Type	Type of object to get.

Returns: A pointer to the object if it exists in the context of the registry, a null pointer otherwise.

◆ try_ctx() [2/2]

template<typename Entity>

template<typename Type >

Type* entt::basic_registry< Entity >::try_ctx ( )

inline

Returns a pointer to an object in the context of the registry.

Template Parameters

Type	Type of object to get.

Returns: A pointer to the object if it exists in the context of the registry, a null pointer otherwise.

◆ try_get() [1/2]

template<typename Entity>

template<typename... Component>

auto entt::basic_registry< Entity >::try_get ( [[maybe_unused] ] const entity_type entity ) const

inline

Returns pointers to the given components for an entity.

Warning: Attempting to use an invalid entity results in undefined behavior.

Note: The registry retains ownership of the pointed-to components.

Template Parameters

Component Types of components to get.

Parameters

entity A valid entity identifier.

Returns: Pointers to the components owned by the entity.

◆ try_get() [2/2]

template<typename Entity>

template<typename... Component>

auto entt::basic_registry< Entity >::try_get ( [[maybe_unused] ] const entity_type entity )

inline

Returns pointers to the given components for an entity.

Warning: Attempting to use an invalid entity results in undefined behavior.

Note: The registry retains ownership of the pointed-to components.

Template Parameters

Component Types of components to get.

Parameters

entity A valid entity identifier.

Returns: Pointers to the components owned by the entity.

◆ unset()

template<typename Entity>

template<typename Type >

void entt::basic_registry< Entity >::unset ( )

inline

Unsets a context variable if it exists.

Template Parameters

Type	Type of object to set.

◆ valid()

template<typename Entity>

bool entt::basic_registry< Entity >::valid ( const entity_type entity ) const

inline

Checks if an entity identifier refers to a valid entity.

Parameters

entity An entity identifier, either valid or not.

Returns: True if the identifier is valid, false otherwise.

◆ version()

template<typename Entity>

static version_type entt::basic_registry< Entity >::version ( const entity_type entity )

inlinestatic

Returns the version stored along with an entity identifier.

Parameters

entity An entity identifier, either valid or not.

Returns: The version stored along with the given entity identifier.

◆ view() [1/2]

template<typename Entity>

template<typename... Component, typename... Exclude>

basic_view<Entity, exclude_t<Exclude...>, Component...> entt::basic_registry< Entity >::view ( exclude_t< Exclude... > = {} ) const

inline

Returns a view for the given components.

This kind of objects are created on the fly and share with the registry its internal data structures.
Feel free to discard a view after the use. Creating and destroying a view is an incredibly cheap operation because they do not require any type of initialization.
As a rule of thumb, storing a view should never be an option.

Views do their best to iterate the smallest set of candidate entities. In particular:

Single component views are incredibly fast and iterate a packed array of entities, all of which has the given component.
Multi component views look at the number of entities available for each component and pick up a reference to the smallest set of candidates to test for the given components.

Views in no way affect the functionalities of the registry nor those of the underlying pools.

Note: Multi component views are pretty fast. However their performance tend to degenerate when the number of components to iterate grows up and the most of the entities have all the given components.
To get a performance boost, consider using a group instead.

Template Parameters

Component	Type of components used to construct the view.
Exclude	Types of components used to filter the view.

Returns: A newly created view.

◆ view() [2/2]

template<typename Entity>

template<typename... Component, typename... Exclude>

basic_view<Entity, exclude_t<Exclude...>, Component...> entt::basic_registry< Entity >::view ( exclude_t< Exclude... > = {} )

inline

Returns a view for the given components.

This kind of objects are created on the fly and share with the registry its internal data structures.
Feel free to discard a view after the use. Creating and destroying a view is an incredibly cheap operation because they do not require any type of initialization.
As a rule of thumb, storing a view should never be an option.

Views do their best to iterate the smallest set of candidate entities. In particular:

Single component views are incredibly fast and iterate a packed array of entities, all of which has the given component.
Multi component views look at the number of entities available for each component and pick up a reference to the smallest set of candidates to test for the given components.

Views in no way affect the functionalities of the registry nor those of the underlying pools.

Note: Multi component views are pretty fast. However their performance tend to degenerate when the number of components to iterate grows up and the most of the entities have all the given components.
To get a performance boost, consider using a group instead.

Template Parameters

Component	Type of components used to construct the view.
Exclude	Types of components used to filter the view.

Returns: A newly created view.

◆ visit() [1/2]

template<typename Entity>

template<typename Func >

void entt::basic_registry< Entity >::visit	(	entity_type	entity,
		Func	func
	)		const

inline

Visits an entity and returns the type info for its components.

The signature of the function should be equivalent to the following:

void(const type_info);

Returned identifiers are those of the components owned by the entity.

See also: type_info

Warning: It's not specified whether a component attached to or removed from the given entity during the visit is returned or not to the caller.

Template Parameters

Func	Type of the function object to invoke.

Parameters

entity	A valid entity identifier.
func	A valid function object.

◆ visit() [2/2]

template<typename Entity>

template<typename Func >

void entt::basic_registry< Entity >::visit ( Func func ) const

inline

Visits a registry and returns the type info for its components.

The signature of the function should be equivalent to the following:

void(const type_info);

Returned identifiers are those of the components managed by the registry.

See also: type_info

Warning: It's not specified whether a component for which a pool is created during the visit is returned or not to the caller.

Template Parameters

Func	Type of the function object to invoke.

Parameters

func	A valid function object.

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

Thirdparty/entt/include/entt/entt.hpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

template<typename Entity> class entt::basic_registry< Entity >

Member Function Documentation

◆ alive()

◆ any()

◆ assign()

◆ capacity() [1/2]

◆ capacity() [2/2]

◆ clear()

◆ create() [1/3]

◆ create() [2/3]

◆ create() [3/3]

◆ ctx() [1/3]

◆ ctx() [2/3]

◆ ctx() [3/3]

◆ ctx_or_set()

◆ current()

◆ data() [1/2]

◆ data() [2/2]

◆ destroy() [1/3]

◆ destroy() [2/3]

◆ destroy() [3/3]

◆ destroyed()

◆ each()

◆ emplace()

◆ emplace_or_replace()

◆ empty()

◆ entity()

◆ get() [1/2]

◆ get() [2/2]

◆ get_or_emplace()

◆ group() [1/2]

◆ group() [2/2]

◆ group_if_exists() [1/2]

◆ group_if_exists() [2/2]

◆ has()

◆ insert() [1/2]

◆ insert() [2/2]

◆ on_construct()

◆ on_destroy()

◆ on_update()

◆ operator=()

◆ orphan()

◆ orphans()

◆ patch()

◆ prepare()

◆ raw() [1/2]

◆ raw() [2/2]

◆ remove() [1/2]

◆ remove() [2/2]

◆ remove_all()

◆ remove_if_exists()

◆ replace()

◆ reserve()

◆ reserve_pools()

◆ runtime_view()

◆ set()

◆ shrink_to_fit()

◆ size() [1/2]

◆ size() [2/2]

◆ sort() [1/2]

◆ sort() [2/2]

◆ sortable() [1/2]

◆ sortable() [2/2]

◆ storage() [1/2]

◆ storage() [2/2]

◆ try_ctx() [1/2]

◆ try_ctx() [2/2]

◆ try_get() [1/2]

◆ try_get() [2/2]

◆ unset()

◆ valid()

◆ version()

◆ view() [1/2]

◆ view() [2/2]

◆ visit() [1/2]

◆ visit() [2/2]

template<typename Entity>
class entt::basic_registry< Entity >