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

#include <entt.hpp>

Public Types
using	entity_type = Entity
	Underlying entity identifier. More...

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

using	size_type = std::size_t
	Unsigned integer type. More...

Public Member Functions
	basic_registry () ENTT_NOEXCEPT=default
	Default constructor. More...

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

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

template<typename... Component>
void	prepare ()
	Prepares pools for the given types if required. More...

template<typename Component >
size_type	size () const ENTT_NOEXCEPT
	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 ENTT_NOEXCEPT
	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...

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

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

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

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

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

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

template<typename... Component>
auto	create ()
	Creates a new entity and returns it. More...

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

template<typename... Component, typename... Exclude>
entity_type	create (entity_type src, const basic_registry &other, exclude_t< Exclude... >={})
	Creates a new entity from a prototype entity. More...

template<typename... Component, typename It , typename... Exclude>
void	create (It first, It last, entity_type src, const basic_registry &other, exclude_t< Exclude... >={})
	Assigns each element in a range an entity from a prototype entity. More...

void	destroy (const entity_type entity)
	Destroys an entity and lets the registry recycle the identifier. 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)	assign (const entity_type entity, [[maybe_unused]] Args &&... args)
	Assigns the given component to an entity. More...

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

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

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

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

template<typename... Component>
auto	try_get ([[maybe_unused]] const entity_type entity) ENTT_NOEXCEPT
	Returns pointers to the given components 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 , typename... Args>
decltype(auto)	assign_or_replace (const entity_type entity, Args &&... args)
	Assigns or replaces the given component for an entity. More...

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

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

template<typename Component >
auto	on_destroy () ENTT_NOEXCEPT
	Returns a sink object for the given component. 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 Component >
void	reset (const entity_type entity)
	Resets the given component for an entity. More...

template<typename Component >
void	reset ()
	Resets the pool of the given component. More...

void	reset ()
	Resets a whole registry. 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, typename... Exclude>
entt::basic_view< Entity, exclude_t< Exclude... >, Component... >	view (exclude_t< Exclude... >={})
	Returns a view for the given components. More...

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

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

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

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

template<typename It >
entt::basic_runtime_view< Entity >	runtime_view (It first, It last) const
	Returns a runtime view for the given components. More...

template<typename... Component, typename... Exclude>
basic_registry	clone (exclude_t< Exclude... >={}) const
	Returns a full or partial copy of a registry. More...

template<typename... Component, typename... Exclude>
void	stomp (const entity_type dst, const entity_type src, const basic_registry &other, exclude_t< Exclude... >={})
	Stomps an entity and its components. More...

template<typename... Component, typename It , typename... Exclude>
void	stomp (It first, It last, const entity_type src, const basic_registry &other, exclude_t< Exclude... >={})
	Stomps the entities in a range and their components. More...

entt::basic_snapshot< Entity >	snapshot () const ENTT_NOEXCEPT
	Returns a temporary object to use to create snapshots. More...

basic_snapshot_loader< Entity >	loader () ENTT_NOEXCEPT
	Returns a temporary object to use to load snapshots. 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 ENTT_NOEXCEPT
	Returns a pointer to an object in the context of the registry. More...

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

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

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

Static Public Member Functions
template<typename Component >
static component	type () ENTT_NOEXCEPT
	Returns the opaque identifier of a component. More...

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

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 and thus create views or groups to iterate them.

Template Parameters

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

Member Typedef Documentation

◆ entity_type

using entt::basic_registry::entity_type = Entity

Underlying entity identifier.

◆ size_type

using entt::basic_registry::size_type = std::size_t

Unsigned integer type.

◆ version_type

using entt::basic_registry::version_type = typename traits_type::version_type

Underlying version type.

Constructor & Destructor Documentation

◆ basic_registry() [1/2]

entt::basic_registry::basic_registry ( )

default

Default constructor.

◆ basic_registry() [2/2]

entt::basic_registry::basic_registry ( basic_registry && )

default

Default move constructor.

Member Function Documentation

◆ alive()

size_type entt::basic_registry::alive ( ) const

inline

Returns the number of entities still in use.

Returns: Number of entities still in use.

◆ assign()

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry::assign	(	const entity_type	entity,
		[[maybe_unused] ] 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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity or if the entity already owns an instance of the given component.

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.

◆ assign_or_replace()

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry::assign_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.assign<Component>(entity, args...);

Prefer this function anyway because it has slightly better performance.

Warning: Attempting to use an invalid entity results in undefined behavior.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

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.

◆ capacity() [1/2]

template<typename Component >

size_type entt::basic_registry::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]

size_type entt::basic_registry::capacity ( ) const

inline

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

Returns: Capacity of the registry.

◆ clone()

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

basic_registry entt::basic_registry::clone ( exclude_t< Exclude... > = {} ) const

inline

Returns a full or partial copy of a registry.

The components must be copyable for obvious reasons. The entities maintain their versions once copied.
If no components are provided, the registry will try to clone all the existing pools. The ones for non-copyable types won't be cloned.

This feature supports exclusion lists. The excluded types have higher priority than those indicated for cloning. An excluded type will never be cloned.

Note: There isn't an efficient way to know if all the entities are assigned at least one component once copied. Therefore, there may be orphans. It is up to the caller to clean up the registry if necessary.; Listeners and groups aren't copied. It is up to the caller to connect the listeners of interest to the new registry and to set up groups.

Warning: Attempting to clone components that aren't copyable results in unexpected behaviors.
A static assertion will abort the compilation when the components provided aren't copy constructible. Otherwise, an assertion will abort the execution at runtime in debug mode in case one or more pools cannot be cloned.

Template Parameters

Component	Types of components to clone.
Exclude	Types of components not to be cloned.

Returns: A fresh copy of the registry.

◆ create() [1/4]

template<typename... Component>

auto entt::basic_registry::create ( )

inline

Creates a new entity and returns it.

There are two kinds of entity identifiers:

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

Users should not care about the type of the returned entity identifier. In case entity identifers are stored around, the valid member function can be used to know if they are still valid or the entity has been destroyed and potentially recycled.
The returned entity has assigned the given components, if any.

The components must be at least default constructible. A compilation error will occur otherwhise.

Template Parameters

Component Types of components to assign to the entity.

Returns: A valid entity identifier if the component list is empty, a tuple containing the entity identifier and the references to the components just created otherwise.

◆ create() [2/4]

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

entity_type entt::basic_registry::create	(	entity_type	src,
		const basic_registry &	other,
		exclude_t< Exclude... >	= `{}`
	)

inline

Creates a new entity from a prototype entity.

See also: create

The components must be copyable for obvious reasons. The source entity must be a valid one.
If no components are provided, the registry will try to copy all the existing types. The non-copyable ones will be ignored.

Note: Specifying the list of components is ways faster than an opaque copy.

Template Parameters

Component	Types of components to copy.
Exclude	Types of components not to be copied.

Parameters

src	A valid entity identifier to be copied.
other	The registry that owns the source entity.

Returns: A valid entity identifier.

◆ create() [3/4]

template<typename... Component, typename It >

auto entt::basic_registry::create	(	It	first,
		It	last
	)

inline

Assigns each element in a range an entity.

See also: create

The components must be at least move and default insertable. A compilation error will occur otherwhise.

Template Parameters

Component	Types of components to assign to the entity.
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.

Returns: No return value if the component list is empty, a tuple containing the iterators to the lists of components just created and sorted the same of the entities otherwise.

◆ create() [4/4]

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

void entt::basic_registry::create	(	It	first,
		It	last,
		entity_type	src,
		const basic_registry &	other,
		exclude_t< Exclude... >	= `{}`
	)

inline

Assigns each element in a range an entity from a prototype entity.

See also: create

The components must be copyable for obvious reasons. The entities must be all valid.
If no components are provided, the registry will try to copy all the existing types. The non-copyable ones will be ignored.

Note: Specifying the list of components is ways faster than an opaque copy and uses the batch creation under the hood.

Template Parameters

Component	Types of components to copy.
It	Type of input iterator.
Exclude	Types of components not to be copied.

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.
src	A valid entity identifier to be copied.
other	The registry that owns the source entity.

◆ ctx() [1/2]

template<typename Type >

const Type& entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid requests.

Template Parameters

Type	Type of object to get.

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

◆ ctx() [2/2]

template<typename Type >

Type& entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid requests.

Template Parameters

Type	Type of object to get.

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

◆ ctx_or_set()

template<typename Type , typename... Args>

Type& entt::basic_registry::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: Reference to the object.

◆ current()

version_type entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode if the registry doesn't own the given entity.

Parameters

entity A valid entity identifier.

Returns: Actual version for the given entity identifier.

◆ data()

template<typename Component >

const entity_type* entt::basic_registry::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.

There are no guarantees on the order of the entities. Use a view if you want to iterate entities and components in the expected order.

Template Parameters

Component Type of component in which one is interested.

Returns: A pointer to the array of entities.

◆ destroy() [1/2]

void entt::basic_registry::destroy ( const entity_type entity )

inline

Destroys an entity and lets the registry recycle the identifier.

When an entity is destroyed, its version is updated and the identifier can be recycled at any time. In case entity identifers are stored around, the valid member function can be used to know if they are still valid or the entity has been destroyed and potentially recycled.

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. An assertion will abort the execution at runtime in debug mode if a violation is detected.; Attempting to use an invalid entity results in undefined behavior.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

Parameters

entity A valid entity identifier.

◆ destroy() [2/2]

template<typename It >

void entt::basic_registry::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 to destroy.
last	An iterator past the last element of the range to destroy.

◆ each()

template<typename Func >

void entt::basic_registry::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.

◆ empty()

template<typename... Component>

bool entt::basic_registry::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()

static entity_type entt::basic_registry::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... Component>

decltype(auto) entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity or if the entity doesn't own an instance of the given component.

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... Component>

decltype(auto) entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity or if the entity doesn't own an instance of the given component.

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_assign()

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry::get_or_assign	(	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.assign<Component>(entity, args...);

Prefer this function anyway because it has slightly better performance.

Warning: Attempting to use an invalid entity results in undefined behavior.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

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() [1/4]

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

entt::basic_group<Entity, exclude_t<Exclude...>, get_t<>, Owned...> entt::basic_registry::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() [2/4]

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

entt::basic_group<Entity, exclude_t<Exclude...>, get_t<>, Owned...> entt::basic_registry::group ( 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.
Exclude	Types of components used to filter the group.

Returns: A newly created group.

◆ group() [3/4]

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

entt::basic_group<Entity, exclude_t<Exclude...>, get_t<Get...>, Owned...> entt::basic_registry::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() [4/4]

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

entt::basic_group<Entity, exclude_t<Exclude...>, get_t<Get...>, Owned...> entt::basic_registry::group	(	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.

◆ has()

template<typename... Component>

bool entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

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.

◆ loader()

basic_snapshot_loader<Entity> entt::basic_registry::loader ( )

inline

Returns a temporary object to use to load snapshots.

A snapshot is either a full or a partial dump of a registry.
It can be used to save and restore its internal state or to keep two or more instances of this class in sync, as an example in a client-server architecture.

Note: The loader returned by this function requires that the registry be empty. In case it isn't, all the data will be automatically deleted before to return.

Returns: A temporary object to use to load snasphosts.

◆ on_construct()

template<typename Component >

auto entt::basic_registry::on_construct ( )

inline

Returns a sink object for the given component.

A sink is an opaque object used to connect listeners to components.
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(Entity, registry<Entity> &, Component &);

Listeners are invoked after the component has been assigned to the entity. The order of invocation of the listeners isn't guaranteed.

Note: Empty types aren't explicitly instantiated. Therefore, temporary objects are returned through signals. They can be caught only by copy or with const references.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ on_destroy()

template<typename Component >

auto entt::basic_registry::on_destroy ( )

inline

Returns a sink object for the given component.

A sink is an opaque object used to connect listeners to components.
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(Entity, registry<Entity> &);

Listeners are invoked before the component has been removed from the entity. The order of invocation of the listeners isn't guaranteed.

Note: Empty types aren't explicitly instantiated. Therefore, temporary objects are returned through signals. They can be caught only by copy or with const references.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ on_replace()

template<typename Component >

auto entt::basic_registry::on_replace ( )

inline

Returns a sink object for the given component.

A sink is an opaque object used to connect listeners to components.
The sink returned by this function can be used to receive notifications whenever an instance of the given component is explicitly replaced.

The function type for a listener is equivalent to:

void(Entity, registry<Entity> &, Component &);

Listeners are invoked before the component has been replaced. The order of invocation of the listeners isn't guaranteed.

Note: Empty types aren't explicitly instantiated. Therefore, temporary objects are returned through signals. They can be caught only by copy or with const references.

See also: sink

Template Parameters

Component Type of component of which to get the sink.

Returns: A temporary sink object.

◆ operator=()

basic_registry& entt::basic_registry::operator= ( basic_registry && )

default

Default move assignment operator.

Returns: This registry.

◆ orphan()

bool entt::basic_registry::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 Func >

void entt::basic_registry::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.

◆ prepare()

template<typename... Component>

void entt::basic_registry::prepare ( )

inline

Prepares pools for the given types if required.

Template Parameters

Component Types of components for which to prepare pools.

◆ raw() [1/2]

template<typename Component >

const Component* entt::basic_registry::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.

There are no guarantees on the order of the components. Use a view if you want to iterate entities and components in the expected order.

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 Component >

Component* entt::basic_registry::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.

There are no guarantees on the order of the components. Use a view if you want to iterate entities and components in the expected order.

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()

template<typename Component >

void entt::basic_registry::remove ( const entity_type entity )

inline

Removes the given component 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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity or if the entity doesn't own an instance of the given component.

Template Parameters

Component Type of component to remove.

Parameters

entity A valid entity identifier.

◆ replace()

template<typename Component , typename... Args>

decltype(auto) entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity or if the entity doesn't own an instance of the given component.

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 newly created component.

◆ reserve()

template<typename... Component>

void entt::basic_registry::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.

◆ reset() [1/3]

template<typename Component >

void entt::basic_registry::reset ( )

inline

Resets the pool of the given component.

For each entity that has an instance of the given component, the component itself is removed and thus destroyed.

Template Parameters

Component Type of component whose pool must be reset.

◆ reset() [2/3]

void entt::basic_registry::reset ( )

inline

Resets a whole registry.

Destroys all the entities. After a call to reset, all the entities still in use are recycled with a new version number. In case entity identifers are stored around, the valid member function can be used to know if they are still valid.

◆ reset() [3/3]

template<typename Component >

void entt::basic_registry::reset ( const entity_type entity )

inline

Resets the given component for an entity.

If the entity has an instance of the component, this function removes the component from the entity. Otherwise it does nothing.

Warning: Attempting to use an invalid entity results in undefined behavior.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

Template Parameters

Component Type of component to reset.

Parameters

entity A valid entity identifier.

◆ runtime_view()

template<typename It >

entt::basic_runtime_view<Entity> entt::basic_registry::runtime_view	(	It	first,
		It	last
	)		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.
This is particularly well suited to plugin systems and mods in general.

Template Parameters

It	Type of input iterator.

Parameters

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

Returns: A newly created runtime view.

◆ set()

template<typename Type , typename... Args>

Type& entt::basic_registry::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... Component>

void entt::basic_registry::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 Component >

size_type entt::basic_registry::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]

size_type entt::basic_registry::size ( ) const

inline

Returns the number of entities created so far.

Returns: Number of entities created so far.

◆ snapshot()

entt::basic_snapshot<Entity> entt::basic_registry::snapshot ( ) const

inline

Returns a temporary object to use to create snapshots.

A snapshot is either a full or a partial dump of a registry.
It can be used to save and restore its internal state or to keep two or more instances of this class in sync, as an example in a client-server architecture.

Returns: A temporary object to use to take snasphosts.

◆ sort() [1/2]

template<typename To , typename From >

void entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case the pool is owned by a group.

Template Parameters

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

◆ sort() [2/2]

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

void entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case the pool is owned by a group.

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.

◆ sortable()

template<typename... Component>

bool entt::basic_registry::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.

◆ stomp() [1/2]

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

void entt::basic_registry::stomp	(	const entity_type	dst,
		const entity_type	src,
		const basic_registry &	other,
		exclude_t< Exclude... >	= `{}`
	)

inline

Stomps an entity and its components.

The components must be copyable for obvious reasons. The entities must be both valid.
If no components are provided, the registry will try to copy all the existing types. The non-copyable ones will be ignored.

This feature supports exclusion lists as an alternative to component lists. An excluded type will never be copied.

Warning: Attempting to copy components that aren't copyable results in unexpected behaviors.
A static assertion will abort the compilation when the components provided aren't copy constructible. Otherwise, an assertion will abort the execution at runtime in debug mode in case one or more types cannot be copied.; Attempting to use invalid entities results in undefined behavior.
An assertion will abort the execution at runtime in debug mode in case of invalid entities.

Template Parameters

Component	Types of components to copy.
Exclude	Types of components not to be copied.

Parameters

dst	A valid entity identifier to copy to.
src	A valid entity identifier to be copied.
other	The registry that owns the source entity.

◆ stomp() [2/2]

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

void entt::basic_registry::stomp	(	It	first,
		It	last,
		const entity_type	src,
		const basic_registry &	other,
		exclude_t< Exclude... >	= `{}`
	)

inline

Stomps the entities in a range and their components.

See also: stomp

Template Parameters

Component	Types of components to copy.
It	Type of input iterator.
Exclude	Types of components not to be copied.

Parameters

first	An iterator to the first element of the range to stomp.
last	An iterator past the last element of the range to stomp.
src	A valid entity identifier to be copied.
other	The registry that owns the source entity.

◆ try_ctx() [1/2]

template<typename Type >

const Type* entt::basic_registry::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 Type >

Type* entt::basic_registry::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... Component>

auto entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

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... Component>

auto entt::basic_registry::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.
An assertion will abort the execution at runtime in debug mode in case of invalid entity.

Template Parameters

Component Types of components to get.

Parameters

entity A valid entity identifier.

Returns: Pointers to the components owned by the entity.

◆ type()

template<typename Component >

static component entt::basic_registry::type ( )

inlinestatic

Returns the opaque identifier of a component.

The given component doesn't need to be necessarily in use.
Identifiers aren't guaranteed to be stable between different runs.

Template Parameters

Component Type of component to query.

Returns: The opaque identifier of the given type of component.

◆ unset()

template<typename Type >

void entt::basic_registry::unset ( )

inline

Unsets a context variable if it exists.

Template Parameters

Type	Type of object to set.

◆ valid()

bool entt::basic_registry::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()

static version_type entt::basic_registry::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... Component, typename... Exclude>

entt::basic_view<Entity, exclude_t<Exclude...>, Component...> entt::basic_registry::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.

◆ view() [2/2]

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

entt::basic_view<Entity, exclude_t<Exclude...>, Component...> entt::basic_registry::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.

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

D:/CadworkJobs/SoftwareProjekte/Lexocad/LexoGit/Lexocad/lexocad/Base/include/Base/entt.hpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

◆ entity_type

◆ size_type

◆ version_type

Constructor & Destructor Documentation

◆ basic_registry() [1/2]

◆ basic_registry() [2/2]

Member Function Documentation

◆ alive()

◆ assign()

◆ assign_or_replace()

◆ capacity() [1/2]

◆ capacity() [2/2]

◆ clone()

◆ create() [1/4]

◆ create() [2/4]

◆ create() [3/4]

◆ create() [4/4]

◆ ctx() [1/2]

◆ ctx() [2/2]

◆ ctx_or_set()

◆ current()

◆ data()

◆ destroy() [1/2]

◆ destroy() [2/2]

◆ each()

◆ empty()

◆ entity()

◆ get() [1/2]

◆ get() [2/2]

◆ get_or_assign()

◆ group() [1/4]

◆ group() [2/4]

◆ group() [3/4]

◆ group() [4/4]

◆ has()

◆ loader()

◆ on_construct()

◆ on_destroy()

◆ on_replace()

◆ operator=()

◆ orphan()

◆ orphans()

◆ prepare()

◆ raw() [1/2]

◆ raw() [2/2]

◆ remove()

◆ replace()

◆ reserve()

◆ reset() [1/3]

◆ reset() [2/3]

◆ reset() [3/3]

◆ runtime_view()

◆ set()

◆ shrink_to_fit()

◆ size() [1/2]

◆ size() [2/2]

◆ snapshot()

◆ sort() [1/2]

◆ sort() [2/2]

◆ sortable()

◆ stomp() [1/2]

◆ stomp() [2/2]

◆ try_ctx() [1/2]

◆ try_ctx() [2/2]

◆ try_get() [1/2]

◆ try_get() [2/2]

◆ type()

◆ unset()

◆ valid()

◆ version()

◆ view() [1/2]

◆ view() [2/2]