Owning group. More...

#include <entt.hpp>

Public Types
using	entity_type = Entity
	Underlying entity identifier.

using	size_type = std::size_t
	Unsigned integer type.

using	iterator = typename basic_sparse_set< Entity >::iterator
	Random access iterator type.

using	reverse_iterator = typename basic_sparse_set< Entity >::reverse_iterator
	Reversed iterator type.

Public Member Functions
	basic_group () ENTT_NOEXCEPT
	Default constructor to use to create empty, invalid groups.

size_type	size () const ENTT_NOEXCEPT
	Returns the number of entities that have the given components. More...

bool	empty () const ENTT_NOEXCEPT
	Checks whether a group is empty. More...

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

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

iterator	begin () const ENTT_NOEXCEPT
	Returns an iterator to the first entity of the group. More...

iterator	end () const ENTT_NOEXCEPT
	Returns an iterator that is past the last entity of the group. More...

reverse_iterator	rbegin () const ENTT_NOEXCEPT
	Returns an iterator to the first entity of the reversed group. More...

reverse_iterator	rend () const ENTT_NOEXCEPT
	Returns an iterator that is past the last entity of the reversed group. More...

entity_type	front () const
	Returns the first entity of the group, if any. More...

entity_type	back () const
	Returns the last entity of the group, if any. More...

iterator	find (const entity_type entt) const
	Finds an entity. More...

entity_type	operator[] (const size_type pos) const
	Returns the identifier that occupies the given position. More...

	operator bool () const ENTT_NOEXCEPT
	Checks if a group is properly initialized. More...

bool	contains (const entity_type entt) const
	Checks if a group contains an entity. More...

template<typename... Component>
decltype(auto)	get (const entity_type entt) const
	Returns the components assigned to the given entity. More...

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

iterable_group	each () const ENTT_NOEXCEPT
	Returns an iterable object to use to visit the group. More...

template<typename... Component, typename Compare , typename Sort = std_sort, typename... Args>
void	sort (Compare compare, Sort algo=Sort{}, Args &&... args) const
	Sort a group according to the given comparison function. More...

Friends
class	basic_registry< Entity >
	A registry is allowed to create groups.

Detailed Description

template<typename Entity, typename... Exclude, typename... Get, typename... Owned>
class entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >

Owning group.

Owning groups return all entities and only the entities that have at least the given components. Moreover:

It's guaranteed that the entity list is tightly packed in memory for fast iterations.
It's guaranteed that the lists of owned components are tightly packed in memory for even faster iterations and to allow direct access.
They stay true to the order of the owned components and all instances have the same order in memory.

The more types of components are owned by a group, the faster it is to iterate them.

Important

Iterators aren't invalidated if:

New instances of the given components are created and assigned to entities.
The entity currently pointed is modified (as an example, if one of the given components is removed from the entity to which the iterator points).
The entity currently pointed is destroyed.

In all other cases, modifying the pools iterated by the group in any way invalidates all the iterators and using them results in undefined behavior.

Note: Groups share references to the underlying data structures of the registry that generated them. Therefore any change to the entities and to the components made by means of the registry are immediately reflected by all the groups. Moreover, sorting an owning group affects all the instance of the same group (it means that users don't have to call sort on each instance to sort all of them because they share the underlying data structure).

Warning: Lifetime of a group must not overcome that of the registry that generated it. In any other case, attempting to use a group results in undefined behavior.

Template Parameters

Entity	A valid entity type (see entt_traits for more details).
Exclude	Types of components used to filter the group.
Get	Types of components observed by the group.
Owned	Types of components owned by the group.

Member Function Documentation

◆ back()

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

entity_type entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::back ( ) const

inline

Returns the last entity of the group, if any.

Returns: The last entity of the group if one exists, the null entity otherwise.

◆ begin()

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

iterator entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::begin ( ) const

inline

Returns an iterator to the first entity of the group.

The returned iterator points to the first entity of the group. If the group is empty, the returned iterator will be equal to end().

Returns: An iterator to the first entity of the group.

◆ contains()

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

bool entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::contains ( const entity_type entt ) const

inline

Checks if a group contains an entity.

Parameters

entt	A valid entity identifier.

Returns: True if the group contains the given entity, false otherwise.

◆ data()

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

const entity_type* entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::data ( ) const

inline

Direct access to the list of entities.

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

Returns: A pointer to the array of entities.

◆ each() [1/2]

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

template<typename Func >

void entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::each ( Func func ) const

inline

Iterates entities and components and applies the given function object to them.

The function object is invoked for each entity. It is provided with the entity itself and a set of references to non-empty components. The constness of the components is as requested.
The signature of the function must be equivalent to one of the following forms:

void(const entity_type, Type &...);

void(Type &...);

Note: Empty types aren't explicitly instantiated and therefore they are never returned during iterations.

Template Parameters

Func	Type of the function object to invoke.

Parameters

func	A valid function object.

◆ each() [2/2]

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

iterable_group entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::each ( ) const

inline

Returns an iterable object to use to visit the group.

The iterable object returns tuples that contain the current entity and a set of references to its non-empty components. The constness of the components is as requested.

Note: Empty types aren't explicitly instantiated and therefore they are never returned during iterations.

Returns: An iterable object to use to visit the group.

◆ empty()

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

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

inline

Checks whether a group is empty.

Returns: True if the group is empty, false otherwise.

◆ end()

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

iterator entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::end ( ) const

inline

Returns an iterator that is past the last entity of the group.

The returned iterator points to the entity following the last entity of the group. Attempting to dereference the returned iterator results in undefined behavior.

Returns: An iterator to the entity following the last entity of the group.

◆ find()

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

iterator entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::find ( const entity_type entt ) const

inline

Finds an entity.

Parameters

entt	A valid entity identifier.

Returns: An iterator to the given entity if it's found, past the end iterator otherwise.

◆ front()

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

entity_type entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::front ( ) const

inline

Returns the first entity of the group, if any.

Returns: The first entity of the group if one exists, the null entity otherwise.

◆ get()

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

template<typename... Component>

decltype(auto) entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::get ( const entity_type entt ) const

inline

Returns the components assigned to the given entity.

Prefer this function instead of registry::get during iterations. It has far better performance than its counterpart.

Warning: Attempting to use an invalid component type results in a compilation error. Attempting to use an entity that doesn't belong to the group results in undefined behavior.

Template Parameters

Component Types of components to get.

Parameters

entt	A valid entity identifier.

Returns: The components assigned to the entity.

◆ operator bool()

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

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

inlineexplicit

Checks if a group is properly initialized.

Returns: True if the group is properly initialized, false otherwise.

◆ operator[]()

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

entity_type entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::operator[] ( const size_type pos ) const

inline

Returns the identifier that occupies the given position.

Parameters

pos	Position of the element to return.

Returns: The identifier that occupies the given position.

◆ raw()

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

template<typename Component >

Component* entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::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()) is always a valid range, even if the container is empty.

Warning: This function is only available for owned types.

Template Parameters

Component Type of component in which one is interested.

Returns: A pointer to the array of components.

◆ rbegin()

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

reverse_iterator entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::rbegin ( ) const

inline

Returns an iterator to the first entity of the reversed group.

The returned iterator points to the first entity of the reversed group. If the group is empty, the returned iterator will be equal to rend().

Returns: An iterator to the first entity of the reversed group.

◆ rend()

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

reverse_iterator entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::rend ( ) const

inline

Returns an iterator that is past the last entity of the reversed group.

The returned iterator points to the entity following the last entity of the reversed group. Attempting to dereference the returned iterator results in undefined behavior.

Returns: An iterator to the entity following the last entity of the reversed group.

◆ size()

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

size_type entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::size ( ) const

inline

Returns the number of entities that have the given components.

Returns: Number of entities that have the given components.

◆ sort()

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

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

void entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >::sort	(	Compare	compare,
		Sort	algo = `Sort{}`,
		Args &&...	args
	)		const

inline

Sort a group according to the given comparison function.

Sort the group so that iterating it with a couple of iterators returns entities and components in the expected order. See begin and end for more details.

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(std::tuple<Component &...>, std::tuple<Component &...>);
bool(const Component &, const Component &);
bool(const Entity, const Entity);

Where Component are either owned types or not but still such that they are iterated by the group.
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.

Template Parameters

Component	Optional types of components to compare.
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.

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

Thirdparty/entt/include/entt/entt.hpp

Public Types

Public Member Functions

Friends

Detailed Description

template<typename Entity, typename... Exclude, typename... Get, typename... Owned> class entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >

Member Function Documentation

◆ back()

◆ begin()

◆ contains()

◆ data()

◆ each() [1/2]

◆ each() [2/2]

◆ empty()

◆ end()

◆ find()

◆ front()

◆ get()

◆ operator bool()

◆ operator[]()

◆ raw()

◆ rbegin()

◆ rend()

◆ size()

◆ sort()

template<typename Entity, typename... Exclude, typename... Get, typename... Owned>
class entt::basic_group< Entity, exclude_t< Exclude... >, get_t< Get... >, Owned... >