Class basic_registry
Synopsis
#include <src/entt/entity/registry.hpp>
template<typename Entity>
class basic_registry
Description
Fast and reliable entity-component system.
- Template Parameters
Entity- A valid entity type (see entt_traits for more details).
Mentioned in
- Entity Component System / The Registry, the Entity and the Component
Methods
| basic_registry overload | Default constructor. | |
| basic_registry overload | Allocates enough memory upon construction to store count pools. | |
| basic_registry overload | Move constructor. | |
| alive | Returns the number of entities still in use. | |
| all_of | Checks if an entity has all the given components. | |
| any_of | Checks if an entity has at least one of the given components. | |
| assign | Assigns identifiers to an empty registry. | |
| capacity | Returns the number of entities that a registry has currently allocated space for. | |
| clear | Clears a whole registry or the pools for the given components. | |
| compact | Removes all tombstones from a registry or only the pools for the given components. | |
| create overload | Creates a new entity or recycles a destroyed one. | |
| create overload | Assigns each element in a range an identifier. | |
| ctx overload | Returns the context object, that is, a general purpose container. | |
| current | Returns the actual version for an identifier. | |
| data | Direct access to the list of entities of a registry. | |
| destroy overload | Destroys an entity and releases its identifier. | |
| destroy overload | Destroys all entities in a range and releases their identifiers. | |
| each | Iterates all the entities that are still in use. | |
| emplace | Assigns the given component to an entity. | |
| emplace_or_replace | Assigns or replaces the given component for an entity. | |
| empty | Checks whether the registry is empty (no entities still in use). | |
| erase overload | Erases the given components from an entity. | |
| erase overload | Erases the given components from all the entities in a range. | |
| get overload | Returns references to the given components for an entity. | |
| get_or_emplace | Returns a reference to the given component for an entity. | |
| group overload | Returns a group for the given components. | |
| group_if_exists overload | Returns a group for the given components. | |
| insert overload | Assigns each entity in a range the given component. | |
| insert overload | Assigns each entity in a range the given components. | |
| on_construct | Returns a sink object for the given component. | |
| on_destroy | Returns a sink object for the given component. | |
| on_update | Returns a sink object for the given component. | |
| operator= | Move assignment operator. | |
| orphan | Checks if an entity has components assigned. | |
| owned | Checks whether the given components belong to any group. | |
| patch | Patches the given component for an entity. | |
| release overload | Releases an identifier. | |
| release overload | Releases all identifiers in a range. | |
| released | Returns the head of the list of released entities. | |
| remove overload | Removes the given components from an entity. | |
| remove overload | Removes the given components from all the entities in a range. | |
| replace | Replaces the given component for an entity. | |
| reserve | Increases the capacity (number of entities) of the registry. | |
| size | Returns the number of entities created so far. | |
| sort overload | Sorts the elements of a given component. | |
| sort overload | Sorts two pools of components in the same way. | |
| sortable | Checks whether a group can be sorted. | |
| storage overload | Returns an iterable object to use to visit a registry. | |
| storage overload | Finds the storage associated with a given name, if any. | |
| storage overload | Returns the storage for a given component type. | |
| try_get overload | Returns pointers to the given components for an entity. | |
| valid | Checks if an identifier refers to a valid entity. | |
| view overload | Returns a view for the given components. |
Source
Lines 220-1491 in src/entt/entity/registry.hpp.
template<typename Entity>
class basic_registry {
using entity_traits = entt_traits<Entity>;
using basic_common_type = basic_sparse_set<Entity>;
template<typename Component>
using storage_type = typename storage_traits<Entity, Component>::storage_type;
template<typename...>
struct group_handler;
template<typename... Exclude, typename... Get, typename... Owned>
struct group_handler<exclude_t<Exclude...>, get_t<Get...>, Owned...> {
// nasty workaround for an issue with the toolset v141 that doesn't accept a fold expression here
static_assert(!std::disjunction_v<std::bool_constant<component_traits<Owned>::in_place_delete>...>, "Groups do not support in-place delete");
std::conditional_t<sizeof...(Owned) == 0, basic_common_type, std::size_t> current{};
template<typename Component>
void maybe_valid_if(basic_registry &owner, const Entity entt) {
[[maybe_unused]] const auto cpools = std::forward_as_tuple(owner.assure<Owned>()...);
const auto is_valid = ((std::is_same_v<Component, Owned> || std::get<storage_type<Owned> &>(cpools).contains(entt)) && ...)
&& ((std::is_same_v<Component, Get> || owner.assure<Get>().contains(entt)) && ...)
&& ((std::is_same_v<Component, Exclude> || !owner.assure<Exclude>().contains(entt)) && ...);
if constexpr(sizeof...(Owned) == 0) {
if(is_valid && !current.contains(entt)) {
current.emplace(entt);
}
} else {
if(is_valid && !(std::get<0>(cpools).index(entt) < current)) {
const auto pos = current++;
(std::get<storage_type<Owned> &>(cpools).swap_elements(std::get<storage_type<Owned> &>(cpools).data()[pos], entt), ...);
}
}
}
void discard_if([[maybe_unused]] basic_registry &owner, const Entity entt) {
if constexpr(sizeof...(Owned) == 0) {
current.remove(entt);
} else {
if(const auto cpools = std::forward_as_tuple(owner.assure<Owned>()...); std::get<0>(cpools).contains(entt) && (std::get<0>(cpools).index(entt) < current)) {
const auto pos = --current;
(std::get<storage_type<Owned> &>(cpools).swap_elements(std::get<storage_type<Owned> &>(cpools).data()[pos], entt), ...);
}
}
}
};
struct group_data {
std::size_t size;
std::unique_ptr<void, void (*)(void *)> group;
bool (*owned)(const id_type) ENTT_NOEXCEPT;
bool (*get)(const id_type) ENTT_NOEXCEPT;
bool (*exclude)(const id_type) ENTT_NOEXCEPT;
};
template<typename Component>
[[nodiscard]] auto &assure(const id_type id = type_hash<Component>::value()) {
static_assert(std::is_same_v<Component, std::decay_t<Component>>, "Non-decayed types not allowed");
auto &&cpool = pools[id];
if(!cpool) {
cpool.reset(new storage_type<Component>{});
cpool->bind(forward_as_any(*this));
}
ENTT_ASSERT(cpool->type() == type_id<Component>(), "Unexpected type");
return static_cast<storage_type<Component> &>(*cpool);
}
template<typename Component>
[[nodiscard]] const auto &assure(const id_type id = type_hash<Component>::value()) const {
static_assert(std::is_same_v<Component, std::decay_t<Component>>, "Non-decayed types not allowed");
if(const auto it = pools.find(id); it != pools.cend()) {
ENTT_ASSERT(it->second->type() == type_id<Component>(), "Unexpected type");
return static_cast<const storage_type<Component> &>(*it->second);
}
static storage_type<Component> placeholder{};
return placeholder;
}
auto generate_identifier(const std::size_t pos) ENTT_NOEXCEPT {
ENTT_ASSERT(pos < entity_traits::to_integral(null), "No entities available");
return entity_traits::combine(static_cast<typename entity_traits::entity_type>(pos), {});
}
auto recycle_identifier() ENTT_NOEXCEPT {
ENTT_ASSERT(free_list != null, "No entities available");
const auto curr = entity_traits::to_entity(free_list);
free_list = entity_traits::combine(entity_traits::to_integral(entities[curr]), tombstone);
return (entities[curr] = entity_traits::combine(curr, entity_traits::to_integral(entities[curr])));
}
auto release_entity(const Entity entity, const typename entity_traits::version_type version) {
const typename entity_traits::version_type vers = version + (version == entity_traits::to_version(tombstone));
entities[entity_traits::to_entity(entity)] = entity_traits::construct(entity_traits::to_integral(free_list), vers);
free_list = entity_traits::combine(entity_traits::to_integral(entity), tombstone);
return vers;
}
public:
/*! @brief Underlying entity identifier. */
using entity_type = Entity;
/*! @brief Underlying version type. */
using version_type = typename entity_traits::version_type;
/*! @brief Unsigned integer type. */
using size_type = std::size_t;
/*! @brief Common type among all storage types. */
using base_type = basic_common_type;
/*! @brief Context type. */
using context = internal::registry_context;
/*! @brief Default constructor. */
basic_registry()
: pools{},
groups{},
entities{},
free_list{tombstone},
vars{} {}
/**
* @brief Allocates enough memory upon construction to store `count` pools.
* @param count The number of pools to allocate memory for.
*/
basic_registry(const size_type count)
: pools{},
groups{},
entities{},
free_list{tombstone},
vars{} {
pools.reserve(count);
}
/**
* @brief Move constructor.
* @param other The instance to move from.
*/
basic_registry(basic_registry &&other)
: pools{std::move(other.pools)},
groups{std::move(other.groups)},
entities{std::move(other.entities)},
free_list{other.free_list},
vars{std::move(other.vars)} {
for(auto &&curr: pools) {
curr.second->bind(forward_as_any(*this));
}
}
/**
* @brief Move assignment operator.
* @param other The instance to move from.
* @return This registry.
*/
basic_registry &operator=(basic_registry &&other) {
pools = std::move(other.pools);
groups = std::move(other.groups);
entities = std::move(other.entities);
free_list = other.free_list;
vars = std::move(other.vars);
for(auto &&curr: pools) {
curr.second->bind(forward_as_any(*this));
}
return *this;
}
/**
* @brief Returns an iterable object to use to _visit_ a registry.
*
* The iterable object returns a pair that contains the name and a reference
* to the current storage.
*
* @return An iterable object to use to _visit_ the registry.
*/
[[nodiscard]] auto storage() ENTT_NOEXCEPT {
return iterable_adaptor{internal::storage_proxy_iterator{pools.begin()}, internal::storage_proxy_iterator{pools.end()}};
}
/*! @copydoc storage */
[[nodiscard]] auto storage() const ENTT_NOEXCEPT {
return iterable_adaptor{internal::storage_proxy_iterator{pools.cbegin()}, internal::storage_proxy_iterator{pools.cend()}};
}
/**
* @brief Finds the storage associated with a given name, if any.
* @param id Name used to map the storage within the registry.
* @return An iterator to the given storage if it's found, past the end
* iterator otherwise.
*/
[[nodiscard]] auto storage(const id_type id) {
return internal::storage_proxy_iterator{pools.find(id)};
}
/**
* @brief Finds the storage associated with a given name, if any.
* @param id Name used to map the storage within the registry.
* @return An iterator to the given storage if it's found, past the end
* iterator otherwise.
*/
[[nodiscard]] auto storage(const id_type id) const {
return internal::storage_proxy_iterator{pools.find(id)};
}
/**
* @brief Returns the storage for a given component type.
* @tparam Component Type of component of which to return the storage.
* @param id Optional name used to map the storage within the registry.
* @return The storage for the given component type.
*/
template<typename Component>
decltype(auto) storage(const id_type id = type_hash<std::remove_const_t<Component>>::value()) {
if constexpr(std::is_const_v<Component>) {
return std::as_const(*this).template storage<std::remove_const_t<Component>>(id);
} else {
return assure<Component>(id);
}
}
/**
* @brief Returns the storage for a given component type.
*
* @warning
* If a storage for the given component doesn't exist yet, a temporary
* placeholder is returned instead.
*
* @tparam Component Type of component of which to return the storage.
* @param id Optional name used to map the storage within the registry.
* @return The storage for the given component type.
*/
template<typename Component>
decltype(auto) storage(const id_type id = type_hash<std::remove_const_t<Component>>::value()) const {
return assure<std::remove_const_t<Component>>(id);
}
/**
* @brief Returns the number of entities created so far.
* @return Number of entities created so far.
*/
[[nodiscard]] size_type size() const ENTT_NOEXCEPT {
return entities.size();
}
/**
* @brief Returns the number of entities still in use.
* @return Number of entities still in use.
*/
[[nodiscard]] size_type alive() const {
auto sz = entities.size();
for(auto curr = free_list; curr != null; --sz) {
curr = entities[entity_traits::to_entity(curr)];
}
return sz;
}
/**
* @brief Increases the capacity (number of entities) of the registry.
* @param cap Desired capacity.
*/
void reserve(const size_type cap) {
entities.reserve(cap);
}
/**
* @brief Returns the number of entities that a registry has currently
* allocated space for.
* @return Capacity of the registry.
*/
[[nodiscard]] size_type capacity() const ENTT_NOEXCEPT {
return entities.capacity();
}
/**
* @brief Checks whether the registry is empty (no entities still in use).
* @return True if the registry is empty, false otherwise.
*/
[[nodiscard]] bool empty() const {
return !alive();
}
/**
* @brief 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 registry is empty.
*
* @warning
* This list contains both valid and destroyed entities and isn't suitable
* for direct use.
*
* @return A pointer to the array of entities.
*/
[[nodiscard]] const entity_type *data() const ENTT_NOEXCEPT {
return entities.data();
}
/**
* @brief Returns the head of the list of released entities.
*
* This function is intended for use in conjunction with `assign`.<br/>
* The returned entity has an invalid identifier in all cases.
*
* @return The head of the list of released entities.
*/
[[nodiscard]] entity_type released() const ENTT_NOEXCEPT {
return free_list;
}
/**
* @brief Checks if an identifier refers to a valid entity.
* @param entity An identifier, either valid or not.
* @return True if the identifier is valid, false otherwise.
*/
[[nodiscard]] bool valid(const entity_type entity) const {
const auto pos = size_type(entity_traits::to_entity(entity));
return (pos < entities.size() && entities[pos] == entity);
}
/**
* @brief Returns the actual version for an identifier.
* @param entity A valid identifier.
* @return The version for the given identifier if valid, the tombstone
* version otherwise.
*/
[[nodiscard]] version_type current(const entity_type entity) const {
const auto pos = size_type(entity_traits::to_entity(entity));
return entity_traits::to_version(pos < entities.size() ? entities[pos] : tombstone);
}
/**
* @brief Creates a new entity or recycles a destroyed one.
* @return A valid identifier.
*/
[[nodiscard]] entity_type create() {
return (free_list == null) ? entities.emplace_back(generate_identifier(entities.size())) : recycle_identifier();
}
/**
* @copybrief create
*
* If the requested entity isn't in use, the suggested identifier is used.
* Otherwise, a new identifier is generated.
*
* @param hint Required identifier.
* @return A valid identifier.
*/
[[nodiscard]] entity_type create(const entity_type hint) {
const auto length = entities.size();
if(hint == null || hint == tombstone) {
return create();
} else if(const auto req = entity_traits::to_entity(hint); !(req < length)) {
entities.resize(size_type(req) + 1u, null);
for(auto pos = length; pos < req; ++pos) {
release_entity(generate_identifier(pos), {});
}
return (entities[req] = hint);
} else if(const auto curr = entity_traits::to_entity(entities[req]); req == curr) {
return create();
} else {
auto *it = &free_list;
for(; entity_traits::to_entity(*it) != req; it = &entities[entity_traits::to_entity(*it)]) {}
*it = entity_traits::combine(curr, entity_traits::to_integral(*it));
return (entities[req] = hint);
}
}
/**
* @brief Assigns each element in a range an identifier.
*
* @sa create
*
* @tparam It Type of forward iterator.
* @param first An iterator to the first element of the range to generate.
* @param last An iterator past the last element of the range to generate.
*/
template<typename It>
void create(It first, It last) {
for(; free_list != null && first != last; ++first) {
*first = recycle_identifier();
}
const auto length = entities.size();
entities.resize(length + std::distance(first, last), null);
for(auto pos = length; first != last; ++first, ++pos) {
*first = entities[pos] = generate_identifier(pos);
}
}
/**
* @brief Assigns identifiers to an empty registry.
*
* This function is intended for use in conjunction with `data`, `size` and
* `destroyed`.<br/>
* 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
* There must be no entities still alive for this to work properly.
*
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
* @param destroyed The head of the list of destroyed entities.
*/
template<typename It>
void assign(It first, It last, const entity_type destroyed) {
ENTT_ASSERT(!alive(), "Entities still alive");
entities.assign(first, last);
free_list = destroyed;
}
/**
* @brief Releases an identifier.
*
* The version is updated and the identifier can be recycled at any time.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @param entity A valid identifier.
* @return The version of the recycled entity.
*/
version_type release(const entity_type entity) {
return release(entity, static_cast<version_type>(entity_traits::to_version(entity) + 1u));
}
/**
* @brief Releases an identifier.
*
* The suggested version or the valid version closest to the suggested one
* is used instead of the implicitly generated version.
*
* @sa release
*
* @param entity A valid identifier.
* @param version A desired version upon destruction.
* @return The version actually assigned to the entity.
*/
version_type release(const entity_type entity, const version_type version) {
ENTT_ASSERT(orphan(entity), "Non-orphan entity");
return release_entity(entity, version);
}
/**
* @brief Releases all identifiers in a range.
*
* @sa release
*
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
*/
template<typename It>
void release(It first, It last) {
for(; first != last; ++first) {
release(*first);
}
}
/**
* @brief Destroys an entity and releases its identifier.
*
* @sa release
*
* @warning
* Adding or removing components to an entity that is being destroyed can
* result in undefined behavior. Attempting to use an invalid entity results
* in undefined behavior.
*
* @param entity A valid identifier.
* @return The version of the recycled entity.
*/
version_type destroy(const entity_type entity) {
return destroy(entity, static_cast<version_type>(entity_traits::to_version(entity) + 1u));
}
/**
* @brief Destroys an entity and releases its identifier.
*
* The suggested version or the valid version closest to the suggested one
* is used instead of the implicitly generated version.
*
* @sa destroy
*
* @param entity A valid identifier.
* @param version A desired version upon destruction.
* @return The version actually assigned to the entity.
*/
version_type destroy(const entity_type entity, const version_type version) {
ENTT_ASSERT(valid(entity), "Invalid entity");
for(size_type pos = pools.size(); pos; --pos) {
pools.begin()[pos - 1u].second->remove(entity);
}
return release_entity(entity, version);
}
/**
* @brief Destroys all entities in a range and releases their identifiers.
*
* @sa destroy
*
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
*/
template<typename It>
void destroy(It first, It last) {
for(; first != last; ++first) {
destroy(*first);
}
}
/**
* @brief Assigns the given component to an entity.
*
* The component must have a proper constructor or be of aggregate type.
*
* @warning
* Attempting to use an invalid entity or to assign a component to an entity
* that already owns it results in undefined behavior.
*
* @tparam Component Type of component to create.
* @tparam Args Types of arguments to use to construct the component.
* @param entity A valid identifier.
* @param args Parameters to use to initialize the component.
* @return A reference to the newly created component.
*/
template<typename Component, typename... Args>
decltype(auto) emplace(const entity_type entity, Args &&...args) {
ENTT_ASSERT(valid(entity), "Invalid entity");
return assure<Component>().emplace(entity, std::forward<Args>(args)...);
}
/**
* @brief Assigns each entity in a range the given component.
*
* @sa emplace
*
* @tparam Component Type of component to create.
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
* @param value An instance of the component to assign.
*/
template<typename Component, typename It>
void insert(It first, It last, const Component &value = {}) {
ENTT_ASSERT(std::all_of(first, last, [this](const auto entity) { return valid(entity); }), "Invalid entity");
assure<Component>().insert(first, last, value);
}
/**
* @brief Assigns each entity in a range the given components.
*
* @sa emplace
*
* @tparam Component Type of component to create.
* @tparam EIt Type of input iterator.
* @tparam CIt Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
* @param from An iterator to the first element of the range of components.
*/
template<typename Component, typename EIt, typename CIt, typename = std::enable_if_t<std::is_same_v<typename std::iterator_traits<CIt>::value_type, Component>>>
void insert(EIt first, EIt last, CIt from) {
ENTT_ASSERT(std::all_of(first, last, [this](const auto entity) { return valid(entity); }), "Invalid entity");
assure<Component>().insert(first, last, from);
}
/**
* @brief Assigns or replaces the given component for an entity.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @tparam Component Type of component to assign or replace.
* @tparam Args Types of arguments to use to construct the component.
* @param entity A valid identifier.
* @param args Parameters to use to initialize the component.
* @return A reference to the newly created component.
*/
template<typename Component, typename... Args>
decltype(auto) emplace_or_replace(const entity_type entity, Args &&...args) {
ENTT_ASSERT(valid(entity), "Invalid entity");
auto &cpool = assure<Component>();
return cpool.contains(entity)
? cpool.patch(entity, [&args...](auto &...curr) { ((curr = Component{std::forward<Args>(args)...}), ...); })
: cpool.emplace(entity, std::forward<Args>(args)...);
}
/**
* @brief Patches the given component for an entity.
*
* The signature of the function should be equivalent to the following:
*
* @code{.cpp}
* void(Component &);
* @endcode
*
* @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.
*
* @tparam Component Type of component to patch.
* @tparam Func Types of the function objects to invoke.
* @param entity A valid identifier.
* @param func Valid function objects.
* @return A reference to the patched component.
*/
template<typename Component, typename... Func>
decltype(auto) patch(const entity_type entity, Func &&...func) {
ENTT_ASSERT(valid(entity), "Invalid entity");
return assure<Component>().patch(entity, std::forward<Func>(func)...);
}
/**
* @brief Replaces the given component for an entity.
*
* The component must have a proper constructor or be of aggregate type.
*
* @warning
* Attempting to use an invalid entity or to replace a component of an
* entity that doesn't own it results in undefined behavior.
*
* @tparam Component Type of component to replace.
* @tparam Args Types of arguments to use to construct the component.
* @param entity A valid identifier.
* @param args Parameters to use to initialize the component.
* @return A reference to the component being replaced.
*/
template<typename Component, typename... Args>
decltype(auto) replace(const entity_type entity, Args &&...args) {
ENTT_ASSERT(valid(entity), "Invalid entity");
return assure<Component>().patch(entity, [&args...](auto &...curr) { ((curr = Component{std::forward<Args>(args)...}), ...); });
}
/**
* @brief Removes the given components from an entity.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @tparam Component Type of component to remove.
* @tparam Other Other types of components to remove.
* @param entity A valid identifier.
* @return The number of components actually removed.
*/
template<typename Component, typename... Other>
size_type remove(const entity_type entity) {
ENTT_ASSERT(valid(entity), "Invalid entity");
return (assure<Component>().remove(entity) + ... + assure<Other>().remove(entity));
}
/**
* @brief Removes the given components from all the entities in a range.
*
* @sa remove
*
* @tparam Component Type of component to remove.
* @tparam Other Other types of components to remove.
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
* @return The number of components actually removed.
*/
template<typename Component, typename... Other, typename It>
size_type remove(It first, It last) {
if constexpr(sizeof...(Other) == 0u) {
ENTT_ASSERT(std::all_of(first, last, [this](const auto entity) { return valid(entity); }), "Invalid entity");
return assure<Component>().remove(std::move(first), std::move(last));
} else {
size_type count{};
for(auto cpools = std::forward_as_tuple(assure<Component>(), assure<Other>()...); first != last; ++first) {
ENTT_ASSERT(valid(*first), "Invalid entity");
count += std::apply([entt = *first](auto &...curr) { return (curr.remove(entt) + ... + 0u); }, cpools);
}
return count;
}
}
/**
* @brief Erases the given components from an entity.
*
* @warning
* Attempting to use an invalid entity or to erase a component from an
* entity that doesn't own it results in undefined behavior.
*
* @tparam Component Types of components to erase.
* @tparam Other Other types of components to erase.
* @param entity A valid identifier.
*/
template<typename Component, typename... Other>
void erase(const entity_type entity) {
ENTT_ASSERT(valid(entity), "Invalid entity");
(assure<Component>().erase(entity), (assure<Other>().erase(entity), ...));
}
/**
* @brief Erases the given components from all the entities in a range.
*
* @sa erase
*
* @tparam Component Types of components to erase.
* @tparam Other Other types of components to erase.
* @tparam It Type of input iterator.
* @param first An iterator to the first element of the range of entities.
* @param last An iterator past the last element of the range of entities.
*/
template<typename Component, typename... Other, typename It>
void erase(It first, It last) {
if constexpr(sizeof...(Other) == 0u) {
ENTT_ASSERT(std::all_of(first, last, [this](const auto entity) { return valid(entity); }), "Invalid entity");
assure<Component>().erase(std::move(first), std::move(last));
} else {
for(auto cpools = std::forward_as_tuple(assure<Component>(), assure<Other>()...); first != last; ++first) {
ENTT_ASSERT(valid(*first), "Invalid entity");
std::apply([entt = *first](auto &...curr) { (curr.erase(entt), ...); }, cpools);
}
}
}
/**
* @brief Removes all tombstones from a registry or only the pools for the
* given components.
* @tparam Component Types of components for which to clear all tombstones.
*/
template<typename... Component>
void compact() {
if constexpr(sizeof...(Component) == 0) {
for(auto &&curr: pools) {
curr.second->compact();
}
} else {
(assure<Component>().compact(), ...);
}
}
/**
* @brief Checks if an entity has all the given components.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @tparam Component Components for which to perform the check.
* @param entity A valid identifier.
* @return True if the entity has all the components, false otherwise.
*/
template<typename... Component>
[[nodiscard]] bool all_of(const entity_type entity) const {
ENTT_ASSERT(valid(entity), "Invalid entity");
return (assure<std::remove_const_t<Component>>().contains(entity) && ...);
}
/**
* @brief Checks if an entity has at least one of the given components.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @tparam Component Components for which to perform the check.
* @param entity A valid identifier.
* @return True if the entity has at least one of the given components,
* false otherwise.
*/
template<typename... Component>
[[nodiscard]] bool any_of(const entity_type entity) const {
ENTT_ASSERT(valid(entity), "Invalid entity");
return (assure<std::remove_const_t<Component>>().contains(entity) || ...);
}
/**
* @brief 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.
*
* @tparam Component Types of components to get.
* @param entity A valid identifier.
* @return References to the components owned by the entity.
*/
template<typename... Component>
[[nodiscard]] decltype(auto) get([[maybe_unused]] const entity_type entity) const {
ENTT_ASSERT(valid(entity), "Invalid entity");
return view<Component...>().template get<const Component...>(entity);
}
/*! @copydoc get */
template<typename... Component>
[[nodiscard]] decltype(auto) get([[maybe_unused]] const entity_type entity) {
ENTT_ASSERT(valid(entity), "Invalid entity");
return view<Component...>().template get<Component...>(entity);
}
/**
* @brief 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.
*
* @warning
* Attempting to use an invalid entity results in undefined behavior.
*
* @tparam Component Type of component to get.
* @tparam Args Types of arguments to use to construct the component.
* @param entity A valid identifier.
* @param args Parameters to use to initialize the component.
* @return Reference to the component owned by the entity.
*/
template<typename Component, typename... Args>
[[nodiscard]] decltype(auto) get_or_emplace(const entity_type entity, Args &&...args) {
ENTT_ASSERT(valid(entity), "Invalid entity");
auto &cpool = assure<Component>();
return cpool.contains(entity) ? cpool.get(entity) : cpool.emplace(entity, std::forward<Args>(args)...);
}
/**
* @brief 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.
*
* @tparam Component Types of components to get.
* @param entity A valid identifier.
* @return Pointers to the components owned by the entity.
*/
template<typename... Component>
[[nodiscard]] auto try_get([[maybe_unused]] const entity_type entity) const {
ENTT_ASSERT(valid(entity), "Invalid entity");
if constexpr(sizeof...(Component) == 1) {
const auto &cpool = assure<std::remove_const_t<Component>...>();
return cpool.contains(entity) ? std::addressof(cpool.get(entity)) : nullptr;
} else {
return std::make_tuple(try_get<Component>(entity)...);
}
}
/*! @copydoc try_get */
template<typename... Component>
[[nodiscard]] auto try_get([[maybe_unused]] const entity_type entity) {
if constexpr(sizeof...(Component) == 1) {
return (const_cast<Component *>(std::as_const(*this).template try_get<Component>(entity)), ...);
} else {
return std::make_tuple(try_get<Component>(entity)...);
}
}
/**
* @brief Clears a whole registry or the pools for the given components.
* @tparam Component Types of components to remove from their entities.
*/
template<typename... Component>
void clear() {
if constexpr(sizeof...(Component) == 0) {
for(auto &&curr: pools) {
curr.second->clear();
}
each([this](const auto entity) { this->release(entity); });
} else {
(assure<Component>().clear(), ...);
}
}
/**
* @brief Iterates all the entities that are still in use.
*
* The signature of the function should be equivalent to the following:
*
* @code{.cpp}
* void(const Entity);
* @endcode
*
* It's not defined whether entities created during iteration are returned.
*
* @tparam Func Type of the function object to invoke.
* @param func A valid function object.
*/
template<typename Func>
void each(Func func) const {
if(free_list == null) {
for(auto pos = entities.size(); pos; --pos) {
func(entities[pos - 1]);
}
} else {
for(auto pos = entities.size(); pos; --pos) {
if(const auto entity = entities[pos - 1]; entity_traits::to_entity(entity) == (pos - 1)) {
func(entity);
}
}
}
}
/**
* @brief Checks if an entity has components assigned.
* @param entity A valid identifier.
* @return True if the entity has no components assigned, false otherwise.
*/
[[nodiscard]] bool orphan(const entity_type entity) const {
ENTT_ASSERT(valid(entity), "Invalid entity");
return std::none_of(pools.cbegin(), pools.cend(), [entity](auto &&curr) { return curr.second->contains(entity); });
}
/**
* @brief Returns a sink object for the given component.
*
* Use this function to receive notifications whenever a new instance of the
* given component is created and assigned to an entity.<br/>
* The function type for a listener is equivalent to:
*
* @code{.cpp}
* void(basic_registry<Entity> &, Entity);
* @endcode
*
* Listeners are invoked **after** assigning the component to the entity.
*
* @sa sink
*
* @tparam Component Type of component of which to get the sink.
* @return A temporary sink object.
*/
template<typename Component>
[[nodiscard]] auto on_construct() {
return assure<Component>().on_construct();
}
/**
* @brief Returns a sink object for the given component.
*
* Use this function to receive notifications whenever an instance of the
* given component is explicitly updated.<br/>
* The function type for a listener is equivalent to:
*
* @code{.cpp}
* void(basic_registry<Entity> &, Entity);
* @endcode
*
* Listeners are invoked **after** updating the component.
*
* @sa sink
*
* @tparam Component Type of component of which to get the sink.
* @return A temporary sink object.
*/
template<typename Component>
[[nodiscard]] auto on_update() {
return assure<Component>().on_update();
}
/**
* @brief Returns a sink object for the given component.
*
* Use this function to receive notifications whenever an instance of the
* given component is removed from an entity and thus destroyed.<br/>
* The function type for a listener is equivalent to:
*
* @code{.cpp}
* void(basic_registry<Entity> &, Entity);
* @endcode
*
* Listeners are invoked **before** removing the component from the entity.
*
* @sa sink
*
* @tparam Component Type of component of which to get the sink.
* @return A temporary sink object.
*/
template<typename Component>
[[nodiscard]] auto on_destroy() {
return assure<Component>().on_destroy();
}
/**
* @brief Returns a view for the given components.
*
* Views are created on the fly and share with the registry its internal
* data structures. Feel free to discard them after the use.<br/>
* Creating and destroying a view is an incredibly cheap operation. As a
* rule of thumb, storing a view should never be an option.
*
* @tparam Component Type of component used to construct the view.
* @tparam Other Other types of components used to construct the view.
* @tparam Exclude Types of components used to filter the view.
* @return A newly created view.
*/
template<typename Component, typename... Other, typename... Exclude>
[[nodiscard]] basic_view<entity_type, get_t<std::add_const_t<Component>, std::add_const_t<Other>...>, exclude_t<Exclude...>> view(exclude_t<Exclude...> = {}) const {
return {assure<std::remove_const_t<Component>>(), assure<std::remove_const_t<Other>>()..., assure<Exclude>()...};
}
/*! @copydoc view */
template<typename Component, typename... Other, typename... Exclude>
[[nodiscard]] basic_view<entity_type, get_t<Component, Other...>, exclude_t<Exclude...>> view(exclude_t<Exclude...> = {}) {
return {assure<std::remove_const_t<Component>>(), assure<std::remove_const_t<Other>>()..., assure<Exclude>()...};
}
/**
* @brief Returns a group for the given components.
*
* Groups are created on the fly and share with the registry its internal
* data structures. Feel free to discard them after the use.<br/>
* Creating and destroying a group is an incredibly cheap operation. 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.<br/>
* However, groups also affect some features of the registry such as the
* creation and destruction of components.
*
* @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.
*
* @tparam Owned Types of components owned by the group.
* @tparam Get Types of components observed by the group.
* @tparam Exclude Types of components used to filter the group.
* @return A newly created group.
*/
template<typename... Owned, typename... Get, typename... Exclude>
[[nodiscard]] basic_group<entity_type, owned_t<Owned...>, get_t<Get...>, exclude_t<Exclude...>> group(get_t<Get...>, exclude_t<Exclude...> = {}) {
static_assert(sizeof...(Owned) + sizeof...(Get) > 0, "Exclusion-only groups are not supported");
static_assert(sizeof...(Owned) + sizeof...(Get) + sizeof...(Exclude) > 1, "Single component groups are not allowed");
using handler_type = group_handler<exclude_t<std::remove_const_t<Exclude>...>, get_t<std::remove_const_t<Get>...>, std::remove_const_t<Owned>...>;
const auto cpools = std::forward_as_tuple(assure<std::remove_const_t<Owned>>()..., assure<std::remove_const_t<Get>>()...);
constexpr auto size = sizeof...(Owned) + sizeof...(Get) + sizeof...(Exclude);
handler_type *handler = nullptr;
auto it = std::find_if(groups.cbegin(), groups.cend(), [size](const auto &gdata) {
return gdata.size == size
&& (gdata.owned(type_hash<std::remove_const_t<Owned>>::value()) && ...)
&& (gdata.get(type_hash<std::remove_const_t<Get>>::value()) && ...)
&& (gdata.exclude(type_hash<Exclude>::value()) && ...);
});
if(it != groups.cend()) {
handler = static_cast<handler_type *>(it->group.get());
} else {
group_data candidate = {
size,
{new handler_type{}, [](void *instance) { delete static_cast<handler_type *>(instance); }},
[]([[maybe_unused]] const id_type ctype) ENTT_NOEXCEPT { return ((ctype == type_hash<std::remove_const_t<Owned>>::value()) || ...); },
[]([[maybe_unused]] const id_type ctype) ENTT_NOEXCEPT { return ((ctype == type_hash<std::remove_const_t<Get>>::value()) || ...); },
[]([[maybe_unused]] const id_type ctype) ENTT_NOEXCEPT { return ((ctype == type_hash<Exclude>::value()) || ...); },
};
handler = static_cast<handler_type *>(candidate.group.get());
const void *maybe_valid_if = nullptr;
const void *discard_if = nullptr;
if constexpr(sizeof...(Owned) == 0) {
groups.push_back(std::move(candidate));
} else {
[[maybe_unused]] auto has_conflict = [size](const auto &gdata) {
const auto overlapping = (0u + ... + gdata.owned(type_hash<std::remove_const_t<Owned>>::value()));
const auto sz = overlapping + (0u + ... + gdata.get(type_hash<std::remove_const_t<Get>>::value())) + (0u + ... + gdata.exclude(type_hash<Exclude>::value()));
return !overlapping || ((sz == size) || (sz == gdata.size));
};
ENTT_ASSERT(std::all_of(groups.cbegin(), groups.cend(), std::move(has_conflict)), "Conflicting groups");
const auto next = std::find_if_not(groups.cbegin(), groups.cend(), [size](const auto &gdata) {
return !(0u + ... + gdata.owned(type_hash<std::remove_const_t<Owned>>::value())) || (size > gdata.size);
});
const auto prev = std::find_if(std::make_reverse_iterator(next), groups.crend(), [](const auto &gdata) {
return (0u + ... + gdata.owned(type_hash<std::remove_const_t<Owned>>::value()));
});
maybe_valid_if = (next == groups.cend() ? maybe_valid_if : next->group.get());
discard_if = (prev == groups.crend() ? discard_if : prev->group.get());
groups.insert(next, std::move(candidate));
}
(on_construct<std::remove_const_t<Owned>>().before(maybe_valid_if).template connect<&handler_type::template maybe_valid_if<std::remove_const_t<Owned>>>(*handler), ...);
(on_construct<std::remove_const_t<Get>>().before(maybe_valid_if).template connect<&handler_type::template maybe_valid_if<std::remove_const_t<Get>>>(*handler), ...);
(on_destroy<Exclude>().before(maybe_valid_if).template connect<&handler_type::template maybe_valid_if<Exclude>>(*handler), ...);
(on_destroy<std::remove_const_t<Owned>>().before(discard_if).template connect<&handler_type::discard_if>(*handler), ...);
(on_destroy<std::remove_const_t<Get>>().before(discard_if).template connect<&handler_type::discard_if>(*handler), ...);
(on_construct<Exclude>().before(discard_if).template connect<&handler_type::discard_if>(*handler), ...);
if constexpr(sizeof...(Owned) == 0) {
for(const auto entity: view<Owned..., Get...>(exclude<Exclude...>)) {
handler->current.emplace(entity);
}
} else {
// we cannot iterate backwards because we want to leave behind valid entities in case of owned types
for(auto *first = std::get<0>(cpools).data(), *last = first + std::get<0>(cpools).size(); first != last; ++first) {
handler->template maybe_valid_if<type_list_element_t<0, type_list<std::remove_const_t<Owned>...>>>(*this, *first);
}
}
}
return {handler->current, std::get<storage_type<std::remove_const_t<Owned>> &>(cpools)..., std::get<storage_type<std::remove_const_t<Get>> &>(cpools)...};
}
/*! @copydoc group */
template<typename... Owned, typename... Get, typename... Exclude>
[[nodiscard]] basic_group<entity_type, owned_t<std::add_const_t<Owned>...>, get_t<std::add_const_t<Get>...>, exclude_t<Exclude...>> group_if_exists(get_t<Get...>, exclude_t<Exclude...> = {}) const {
auto it = std::find_if(groups.cbegin(), groups.cend(), [](const auto &gdata) {
return gdata.size == (sizeof...(Owned) + sizeof...(Get) + sizeof...(Exclude))
&& (gdata.owned(type_hash<std::remove_const_t<Owned>>::value()) && ...)
&& (gdata.get(type_hash<std::remove_const_t<Get>>::value()) && ...)
&& (gdata.exclude(type_hash<Exclude>::value()) && ...);
});
if(it == groups.cend()) {
return {};
} else {
using handler_type = group_handler<exclude_t<std::remove_const_t<Exclude>...>, get_t<std::remove_const_t<Get>...>, std::remove_const_t<Owned>...>;
return {static_cast<handler_type *>(it->group.get())->current, assure<std::remove_const_t<Owned>>()..., assure<std::remove_const_t<Get>>()...};
}
}
/*! @copydoc group */
template<typename... Owned, typename... Exclude>
[[nodiscard]] basic_group<entity_type, owned_t<Owned...>, get_t<>, exclude_t<Exclude...>> group(exclude_t<Exclude...> = {}) {
return group<Owned...>(get_t<>{}, exclude<Exclude...>);
}
/*! @copydoc group */
template<typename... Owned, typename... Exclude>
[[nodiscard]] basic_group<entity_type, owned_t<std::add_const_t<Owned>...>, get_t<>, exclude_t<Exclude...>> group_if_exists(exclude_t<Exclude...> = {}) const {
return group_if_exists<std::add_const_t<Owned>...>(get_t<>{}, exclude<Exclude...>);
}
/**
* @brief Checks whether the given components belong to any group.
* @tparam Component Types of components in which one is interested.
* @return True if the pools of the given components are _free_, false
* otherwise.
*/
template<typename... Component>
[[nodiscard]] bool owned() const {
return std::any_of(groups.cbegin(), groups.cend(), [](auto &&gdata) { return (gdata.owned(type_hash<std::remove_const_t<Component>>::value()) || ...); });
}
/**
* @brief Checks whether a group can be sorted.
* @tparam Owned Types of components owned by the group.
* @tparam Get Types of components observed by the group.
* @tparam Exclude Types of components used to filter the group.
* @return True if the group can be sorted, false otherwise.
*/
template<typename... Owned, typename... Get, typename... Exclude>
[[nodiscard]] bool sortable(const basic_group<entity_type, owned_t<Owned...>, get_t<Get...>, exclude_t<Exclude...>> &) ENTT_NOEXCEPT {
constexpr auto size = sizeof...(Owned) + sizeof...(Get) + sizeof...(Exclude);
auto pred = [size](const auto &gdata) { return (0u + ... + gdata.owned(type_hash<std::remove_const_t<Owned>>::value())) && (size < gdata.size); };
return std::find_if(groups.cbegin(), groups.cend(), std::move(pred)) == groups.cend();
}
/**
* @brief Sorts the elements of a given component.
*
* The order remains valid until a component of the given type is assigned
* to or removed from an entity.<br/>
* The comparison function object returns `true` if the first element is
* _less_ than the second one, `false` otherwise. Its signature is also
* equivalent to one of the following:
*
* @code{.cpp}
* bool(const Entity, const Entity);
* bool(const Component &, const Component &);
* @endcode
*
* Moreover, it shall induce a _strict weak ordering_ on the values.<br/>
* The sort function object offers an `operator()` that accepts:
*
* * 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 object to use to compare the elements.
*
* The comparison 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.
*
* @tparam Component Type of components to sort.
* @tparam Compare Type of comparison function object.
* @tparam Sort Type of sort function object.
* @tparam Args Types of arguments to forward to the sort function object.
* @param compare A valid comparison function object.
* @param algo A valid sort function object.
* @param args Arguments to forward to the sort function object, if any.
*/
template<typename Component, typename Compare, typename Sort = std_sort, typename... Args>
void sort(Compare compare, Sort algo = Sort{}, Args &&...args) {
ENTT_ASSERT(!owned<Component>(), "Cannot sort owned storage");
auto &cpool = assure<Component>();
if constexpr(std::is_invocable_v<Compare, decltype(cpool.get({})), decltype(cpool.get({}))>) {
auto comp = [&cpool, compare = std::move(compare)](const auto lhs, const auto rhs) { return compare(std::as_const(cpool.get(lhs)), std::as_const(cpool.get(rhs))); };
cpool.sort(std::move(comp), std::move(algo), std::forward<Args>(args)...);
} else {
cpool.sort(std::move(compare), std::move(algo), std::forward<Args>(args)...);
}
}
/**
* @brief Sorts two pools of components in the same way.
*
* Being `To` and `From` the two sets, after invoking this function an
* iterator for `To` returns elements according to the following rules:
*
* * All entities in `To` that are also in `From` are returned first
* according to the order they have in `From`.
* * All entities in `To` that are not in `From` are returned in no
* particular order after all the other entities.
*
* Any subsequent change to `From` won't affect the order in `To`.
*
* @warning
* Pools of components owned by a group cannot be sorted.
*
* @tparam To Type of components to sort.
* @tparam From Type of components to use to sort.
*/
template<typename To, typename From>
void sort() {
ENTT_ASSERT(!owned<To>(), "Cannot sort owned storage");
assure<To>().respect(assure<From>());
}
/**
* @brief Returns the context object, that is, a general purpose container.
* @return The context object, that is, a general purpose container.
*/
context &ctx() ENTT_NOEXCEPT {
return vars;
}
/*! @copydoc ctx */
const context &ctx() const ENTT_NOEXCEPT {
return vars;
}
private:
dense_map<id_type, std::unique_ptr<base_type>, identity> pools;
std::vector<group_data> groups;
std::vector<entity_type> entities;
entity_type free_list;
context vars;
};