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905 lines
34 KiB
905 lines
34 KiB
#ifndef ENTT_ENTITY_GROUP_HPP
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#define ENTT_ENTITY_GROUP_HPP
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#include <tuple>
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#include <type_traits>
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#include <utility>
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#include "../config/config.h"
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#include "../core/iterator.hpp"
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#include "../core/type_traits.hpp"
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#include "component.hpp"
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#include "entity.hpp"
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#include "fwd.hpp"
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#include "sparse_set.hpp"
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#include "storage.hpp"
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#include "utility.hpp"
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namespace entt {
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/**
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* @brief Group.
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*
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* Primary template isn't defined on purpose. All the specializations give a
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* compile-time error, but for a few reasonable cases.
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*/
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template<typename, typename, typename, typename>
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class basic_group;
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/**
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* @brief Non-owning group.
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*
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* A non-owning group returns all entities and only the entities that have at
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* least the given components. Moreover, it's guaranteed that the entity list
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* is tightly packed in memory for fast iterations.
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*
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* @b Important
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*
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* Iterators aren't invalidated if:
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*
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* * New instances of the given components are created and assigned to entities.
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* * The entity currently pointed is modified (as an example, if one of the
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* given components is removed from the entity to which the iterator points).
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* * The entity currently pointed is destroyed.
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*
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* In all other cases, modifying the pools iterated by the group in any way
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* invalidates all the iterators and using them results in undefined behavior.
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*
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* @note
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* Groups share references to the underlying data structures of the registry
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* that generated them. Therefore any change to the entities and to the
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* components made by means of the registry are immediately reflected by all the
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* groups.<br/>
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* Moreover, sorting a non-owning group affects all the instances of the same
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* group (it means that users don't have to call `sort` on each instance to sort
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* all of them because they _share_ entities and components).
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*
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* @warning
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* Lifetime of a group must not overcome that of the registry that generated it.
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* In any other case, attempting to use a group results in undefined behavior.
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*
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* @tparam Entity A valid entity type (see entt_traits for more details).
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* @tparam Get Type of components observed by the group.
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* @tparam Exclude Types of components used to filter the group.
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*/
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template<typename Entity, typename... Get, typename... Exclude>
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class basic_group<Entity, owned_t<>, get_t<Get...>, exclude_t<Exclude...>> {
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/*! @brief A registry is allowed to create groups. */
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friend class basic_registry<Entity>;
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template<typename Comp>
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using storage_type = constness_as_t<typename storage_traits<Entity, std::remove_const_t<Comp>>::storage_type, Comp>;
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using basic_common_type = std::common_type_t<typename storage_type<Get>::base_type...>;
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struct extended_group_iterator final {
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using difference_type = std::ptrdiff_t;
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using value_type = decltype(std::tuple_cat(std::tuple<Entity>{}, std::declval<basic_group>().get({})));
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using pointer = input_iterator_pointer<value_type>;
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using reference = value_type;
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using iterator_category = std::input_iterator_tag;
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extended_group_iterator() = default;
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extended_group_iterator(typename basic_common_type::iterator from, const std::tuple<storage_type<Get> *...> &args)
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: it{from},
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pools{args} {}
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extended_group_iterator &operator++() ENTT_NOEXCEPT {
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return ++it, *this;
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}
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extended_group_iterator operator++(int) ENTT_NOEXCEPT {
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extended_group_iterator orig = *this;
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return ++(*this), orig;
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}
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[[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
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const auto entt = *it;
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return std::tuple_cat(std::make_tuple(entt), std::get<storage_type<Get> *>(pools)->get_as_tuple(entt)...);
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}
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[[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
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return operator*();
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}
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[[nodiscard]] bool operator==(const extended_group_iterator &other) const ENTT_NOEXCEPT {
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return other.it == it;
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}
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[[nodiscard]] bool operator!=(const extended_group_iterator &other) const ENTT_NOEXCEPT {
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return !(*this == other);
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}
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private:
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typename basic_common_type::iterator it;
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std::tuple<storage_type<Get> *...> pools;
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};
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basic_group(basic_common_type &ref, storage_type<Get> &...gpool) ENTT_NOEXCEPT
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: handler{&ref},
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pools{&gpool...} {}
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public:
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/*! @brief Underlying entity identifier. */
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using entity_type = Entity;
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/*! @brief Unsigned integer type. */
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using size_type = std::size_t;
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/*! @brief Common type among all storage types. */
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using base_type = basic_common_type;
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/*! @brief Random access iterator type. */
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using iterator = typename base_type::iterator;
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/*! @brief Reversed iterator type. */
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using reverse_iterator = typename base_type::reverse_iterator;
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/*! @brief Iterable group type. */
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using iterable = iterable_adaptor<extended_group_iterator>;
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/*! @brief Default constructor to use to create empty, invalid groups. */
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basic_group() ENTT_NOEXCEPT
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: handler{} {}
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/**
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* @brief Returns a const reference to the underlying handler.
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* @return A const reference to the underlying handler.
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*/
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const base_type &handle() const ENTT_NOEXCEPT {
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return *handler;
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}
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/**
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* @brief Returns the storage for a given component type.
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* @tparam Comp Type of component of which to return the storage.
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* @return The storage for the given component type.
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*/
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template<typename Comp>
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[[nodiscard]] decltype(auto) storage() const ENTT_NOEXCEPT {
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return *std::get<storage_type<Comp> *>(pools);
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}
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/**
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* @brief Returns the storage for a given component type.
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* @tparam Comp Index of component of which to return the storage.
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* @return The storage for the given component type.
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*/
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template<std::size_t Comp>
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[[nodiscard]] decltype(auto) storage() const ENTT_NOEXCEPT {
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return *std::get<Comp>(pools);
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}
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/**
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* @brief Returns the number of entities that have the given components.
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* @return Number of entities that have the given components.
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*/
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[[nodiscard]] size_type size() const ENTT_NOEXCEPT {
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return *this ? handler->size() : size_type{};
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}
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/**
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* @brief Returns the number of elements that a group has currently
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* allocated space for.
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* @return Capacity of the group.
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*/
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[[nodiscard]] size_type capacity() const ENTT_NOEXCEPT {
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return *this ? handler->capacity() : size_type{};
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}
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/*! @brief Requests the removal of unused capacity. */
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void shrink_to_fit() {
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if(*this) {
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handler->shrink_to_fit();
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}
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}
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/**
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* @brief Checks whether a group is empty.
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* @return True if the group is empty, false otherwise.
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*/
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[[nodiscard]] bool empty() const ENTT_NOEXCEPT {
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return !*this || handler->empty();
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}
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/**
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* @brief Returns an iterator to the first entity of the group.
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*
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* The returned iterator points to the first entity of the group. If the
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* group is empty, the returned iterator will be equal to `end()`.
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*
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* @return An iterator to the first entity of the group.
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*/
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[[nodiscard]] iterator begin() const ENTT_NOEXCEPT {
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return *this ? handler->begin() : iterator{};
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}
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/**
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* @brief Returns an iterator that is past the last entity of the group.
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*
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* The returned iterator points to the entity following the last entity of
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* the group. Attempting to dereference the returned iterator results in
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* undefined behavior.
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*
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* @return An iterator to the entity following the last entity of the
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* group.
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*/
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[[nodiscard]] iterator end() const ENTT_NOEXCEPT {
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return *this ? handler->end() : iterator{};
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}
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/**
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* @brief Returns an iterator to the first entity of the reversed group.
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*
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* The returned iterator points to the first entity of the reversed group.
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* If the group is empty, the returned iterator will be equal to `rend()`.
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*
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* @return An iterator to the first entity of the reversed group.
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*/
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[[nodiscard]] reverse_iterator rbegin() const ENTT_NOEXCEPT {
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return *this ? handler->rbegin() : reverse_iterator{};
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}
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/**
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* @brief Returns an iterator that is past the last entity of the reversed
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* group.
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*
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* The returned iterator points to the entity following the last entity of
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* the reversed group. Attempting to dereference the returned iterator
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* results in undefined behavior.
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*
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* @return An iterator to the entity following the last entity of the
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* reversed group.
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*/
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[[nodiscard]] reverse_iterator rend() const ENTT_NOEXCEPT {
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return *this ? handler->rend() : reverse_iterator{};
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}
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/**
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* @brief Returns the first entity of the group, if any.
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* @return The first entity of the group if one exists, the null entity
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* otherwise.
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*/
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[[nodiscard]] entity_type front() const ENTT_NOEXCEPT {
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const auto it = begin();
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return it != end() ? *it : null;
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}
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/**
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* @brief Returns the last entity of the group, if any.
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* @return The last entity of the group if one exists, the null entity
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* otherwise.
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*/
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[[nodiscard]] entity_type back() const ENTT_NOEXCEPT {
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const auto it = rbegin();
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return it != rend() ? *it : null;
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}
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/**
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* @brief Finds an entity.
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* @param entt A valid identifier.
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* @return An iterator to the given entity if it's found, past the end
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* iterator otherwise.
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*/
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[[nodiscard]] iterator find(const entity_type entt) const ENTT_NOEXCEPT {
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const auto it = *this ? handler->find(entt) : iterator{};
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return it != end() && *it == entt ? it : end();
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}
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/**
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* @brief Returns the identifier that occupies the given position.
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* @param pos Position of the element to return.
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* @return The identifier that occupies the given position.
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*/
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[[nodiscard]] entity_type operator[](const size_type pos) const {
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return begin()[pos];
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}
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/**
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* @brief Checks if a group is properly initialized.
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* @return True if the group is properly initialized, false otherwise.
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*/
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[[nodiscard]] explicit operator bool() const ENTT_NOEXCEPT {
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return handler != nullptr;
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}
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/**
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* @brief Checks if a group contains an entity.
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* @param entt A valid identifier.
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* @return True if the group contains the given entity, false otherwise.
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*/
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[[nodiscard]] bool contains(const entity_type entt) const ENTT_NOEXCEPT {
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return *this && handler->contains(entt);
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}
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/**
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* @brief Returns the components assigned to the given entity.
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*
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* Prefer this function instead of `registry::get` during iterations. It has
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* far better performance than its counterpart.
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*
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* @warning
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* Attempting to use an invalid component type results in a compilation
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* error. Attempting to use an entity that doesn't belong to the group
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* results in undefined behavior.
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*
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* @tparam Comp Types of components to get.
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* @param entt A valid identifier.
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* @return The components assigned to the entity.
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*/
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template<typename... Comp>
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[[nodiscard]] decltype(auto) get(const entity_type entt) const {
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ENTT_ASSERT(contains(entt), "Group does not contain entity");
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if constexpr(sizeof...(Comp) == 0) {
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return std::tuple_cat(std::get<storage_type<Get> *>(pools)->get_as_tuple(entt)...);
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} else if constexpr(sizeof...(Comp) == 1) {
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return (std::get<storage_type<Comp> *>(pools)->get(entt), ...);
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} else {
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return std::tuple_cat(std::get<storage_type<Comp> *>(pools)->get_as_tuple(entt)...);
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}
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}
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/**
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* @brief Iterates entities and components and applies the given function
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* object to them.
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*
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* The function object is invoked for each entity. It is provided with the
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* entity itself and a set of references to non-empty components. The
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* _constness_ of the components is as requested.<br/>
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* The signature of the function must be equivalent to one of the following
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* forms:
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*
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* @code{.cpp}
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* void(const entity_type, Type &...);
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* void(Type &...);
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* @endcode
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*
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* @note
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* Empty types aren't explicitly instantiated and therefore they are never
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* returned during iterations.
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*
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* @tparam Func Type of the function object to invoke.
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* @param func A valid function object.
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*/
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template<typename Func>
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void each(Func func) const {
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for(const auto entt: *this) {
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if constexpr(is_applicable_v<Func, decltype(std::tuple_cat(std::tuple<entity_type>{}, std::declval<basic_group>().get({})))>) {
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std::apply(func, std::tuple_cat(std::make_tuple(entt), get(entt)));
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} else {
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std::apply(func, get(entt));
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}
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}
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}
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/**
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* @brief Returns an iterable object to use to _visit_ a group.
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*
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* The iterable object returns tuples that contain the current entity and a
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* set of references to its non-empty components. The _constness_ of the
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* components is as requested.
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*
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* @note
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* Empty types aren't explicitly instantiated and therefore they are never
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* returned during iterations.
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*
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* @return An iterable object to use to _visit_ the group.
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*/
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[[nodiscard]] iterable each() const ENTT_NOEXCEPT {
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return handler ? iterable{extended_group_iterator{handler->begin(), pools}, extended_group_iterator{handler->end(), pools}}
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: iterable{extended_group_iterator{{}, pools}, extended_group_iterator{{}, pools}};
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}
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/**
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* @brief Sort a group according to the given comparison function.
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*
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* Sort the group so that iterating it with a couple of iterators returns
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* entities and components in the expected order. See `begin` and `end` for
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* more details.
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*
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* The comparison function object must return `true` if the first element
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* is _less_ than the second one, `false` otherwise. The signature of the
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* comparison function should be equivalent to one of the following:
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*
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* @code{.cpp}
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* bool(std::tuple<Component &...>, std::tuple<Component &...>);
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* bool(const Component &..., const Component &...);
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* bool(const Entity, const Entity);
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* @endcode
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*
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* Where `Component` are such that they are iterated by the group.<br/>
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* Moreover, the comparison function object shall induce a
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* _strict weak ordering_ on the values.
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*
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* The sort function object must offer a member function template
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* `operator()` that accepts three arguments:
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*
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* * An iterator to the first element of the range to sort.
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* * An iterator past the last element of the range to sort.
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* * A comparison function to use to compare the elements.
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*
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* @tparam Comp Optional types of components to compare.
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* @tparam Compare Type of comparison function object.
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* @tparam Sort Type of sort function object.
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* @tparam Args Types of arguments to forward to the sort function object.
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* @param compare A valid comparison function object.
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* @param algo A valid sort function object.
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* @param args Arguments to forward to the sort function object, if any.
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*/
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template<typename... Comp, typename Compare, typename Sort = std_sort, typename... Args>
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void sort(Compare compare, Sort algo = Sort{}, Args &&...args) {
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if(*this) {
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if constexpr(sizeof...(Comp) == 0) {
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static_assert(std::is_invocable_v<Compare, const entity_type, const entity_type>, "Invalid comparison function");
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handler->sort(std::move(compare), std::move(algo), std::forward<Args>(args)...);
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} else {
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auto comp = [this, &compare](const entity_type lhs, const entity_type rhs) {
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if constexpr(sizeof...(Comp) == 1) {
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return compare((std::get<storage_type<Comp> *>(pools)->get(lhs), ...), (std::get<storage_type<Comp> *>(pools)->get(rhs), ...));
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} else {
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return compare(std::forward_as_tuple(std::get<storage_type<Comp> *>(pools)->get(lhs)...), std::forward_as_tuple(std::get<storage_type<Comp> *>(pools)->get(rhs)...));
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}
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};
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handler->sort(std::move(comp), std::move(algo), std::forward<Args>(args)...);
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}
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}
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}
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/**
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* @brief Sort the shared pool of entities according to the given component.
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*
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* Non-owning groups of the same type share with the registry a pool of
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* entities with its own order that doesn't depend on the order of any pool
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* of components. Users can order the underlying data structure so that it
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* respects the order of the pool of the given component.
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*
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* @note
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* The shared pool of entities and thus its order is affected by the changes
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* to each and every pool that it tracks. Therefore changes to those pools
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* can quickly ruin the order imposed to the pool of entities shared between
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* the non-owning groups.
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*
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* @tparam Comp Type of component to use to impose the order.
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*/
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template<typename Comp>
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void sort() const {
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if(*this) {
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handler->respect(*std::get<storage_type<Comp> *>(pools));
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}
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}
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private:
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base_type *const handler;
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const std::tuple<storage_type<Get> *...> pools;
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};
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/**
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* @brief Owning group.
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*
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* Owning groups return all entities and only the entities that have at least
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* the given components. Moreover:
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*
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* * It's guaranteed that the entity list is tightly packed in memory for fast
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* iterations.
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* * It's guaranteed that the lists of owned components are tightly packed in
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* memory for even faster iterations and to allow direct access.
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* * They stay true to the order of the owned components and all instances have
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* the same order in memory.
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*
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* The more types of components are owned by a group, the faster it is to
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* iterate them.
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*
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* @b Important
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*
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* Iterators aren't invalidated if:
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*
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* * New instances of the given components are created and assigned to entities.
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* * The entity currently pointed is modified (as an example, if one of the
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* given components is removed from the entity to which the iterator points).
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* * The entity currently pointed is destroyed.
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*
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* 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.
|
|
*
|
|
* @tparam Entity A valid entity type (see entt_traits for more details).
|
|
* @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.
|
|
*/
|
|
template<typename Entity, typename... Owned, typename... Get, typename... Exclude>
|
|
class basic_group<Entity, owned_t<Owned...>, get_t<Get...>, exclude_t<Exclude...>> {
|
|
/*! @brief A registry is allowed to create groups. */
|
|
friend class basic_registry<Entity>;
|
|
|
|
template<typename Comp>
|
|
using storage_type = constness_as_t<typename storage_traits<Entity, std::remove_const_t<Comp>>::storage_type, Comp>;
|
|
|
|
using basic_common_type = std::common_type_t<typename storage_type<Owned>::base_type..., typename storage_type<Get>::base_type...>;
|
|
|
|
class extended_group_iterator final {
|
|
template<typename Type>
|
|
auto index_to_element(storage_type<Type> &cpool) const {
|
|
if constexpr(ignore_as_empty_v<std::remove_const_t<Type>>) {
|
|
return std::make_tuple();
|
|
} else {
|
|
return std::forward_as_tuple(cpool.rbegin()[it.index()]);
|
|
}
|
|
}
|
|
|
|
public:
|
|
using difference_type = std::ptrdiff_t;
|
|
using value_type = decltype(std::tuple_cat(std::tuple<Entity>{}, std::declval<basic_group>().get({})));
|
|
using pointer = input_iterator_pointer<value_type>;
|
|
using reference = value_type;
|
|
using iterator_category = std::input_iterator_tag;
|
|
|
|
extended_group_iterator() = default;
|
|
|
|
template<typename... Other>
|
|
extended_group_iterator(typename basic_common_type::iterator from, const std::tuple<storage_type<Owned> *..., storage_type<Get> *...> &cpools)
|
|
: it{from},
|
|
pools{cpools} {}
|
|
|
|
extended_group_iterator &operator++() ENTT_NOEXCEPT {
|
|
return ++it, *this;
|
|
}
|
|
|
|
extended_group_iterator operator++(int) ENTT_NOEXCEPT {
|
|
extended_group_iterator orig = *this;
|
|
return ++(*this), orig;
|
|
}
|
|
|
|
[[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
|
|
return std::tuple_cat(
|
|
std::make_tuple(*it),
|
|
index_to_element<Owned>(*std::get<storage_type<Owned> *>(pools))...,
|
|
std::get<storage_type<Get> *>(pools)->get_as_tuple(*it)...);
|
|
}
|
|
|
|
[[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
|
|
return operator*();
|
|
}
|
|
|
|
[[nodiscard]] bool operator==(const extended_group_iterator &other) const ENTT_NOEXCEPT {
|
|
return other.it == it;
|
|
}
|
|
|
|
[[nodiscard]] bool operator!=(const extended_group_iterator &other) const ENTT_NOEXCEPT {
|
|
return !(*this == other);
|
|
}
|
|
|
|
private:
|
|
typename basic_common_type::iterator it;
|
|
std::tuple<storage_type<Owned> *..., storage_type<Get> *...> pools;
|
|
};
|
|
|
|
basic_group(const std::size_t &extent, storage_type<Owned> &...opool, storage_type<Get> &...gpool) ENTT_NOEXCEPT
|
|
: pools{&opool..., &gpool...},
|
|
length{&extent} {}
|
|
|
|
public:
|
|
/*! @brief Underlying entity identifier. */
|
|
using entity_type = Entity;
|
|
/*! @brief Unsigned integer type. */
|
|
using size_type = std::size_t;
|
|
/*! @brief Common type among all storage types. */
|
|
using base_type = basic_common_type;
|
|
/*! @brief Random access iterator type. */
|
|
using iterator = typename base_type::iterator;
|
|
/*! @brief Reversed iterator type. */
|
|
using reverse_iterator = typename base_type::reverse_iterator;
|
|
/*! @brief Iterable group type. */
|
|
using iterable = iterable_adaptor<extended_group_iterator>;
|
|
|
|
/*! @brief Default constructor to use to create empty, invalid groups. */
|
|
basic_group() ENTT_NOEXCEPT
|
|
: length{} {}
|
|
|
|
/**
|
|
* @brief Returns the storage for a given component type.
|
|
* @tparam Comp Type of component of which to return the storage.
|
|
* @return The storage for the given component type.
|
|
*/
|
|
template<typename Comp>
|
|
[[nodiscard]] decltype(auto) storage() const ENTT_NOEXCEPT {
|
|
return *std::get<storage_type<Comp> *>(pools);
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the storage for a given component type.
|
|
* @tparam Comp Index of component of which to return the storage.
|
|
* @return The storage for the given component type.
|
|
*/
|
|
template<std::size_t Comp>
|
|
[[nodiscard]] decltype(auto) storage() const ENTT_NOEXCEPT {
|
|
return *std::get<Comp>(pools);
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the number of entities that have the given components.
|
|
* @return Number of entities that have the given components.
|
|
*/
|
|
[[nodiscard]] size_type size() const ENTT_NOEXCEPT {
|
|
return *this ? *length : size_type{};
|
|
}
|
|
|
|
/**
|
|
* @brief Checks whether a group is empty.
|
|
* @return True if the group is empty, false otherwise.
|
|
*/
|
|
[[nodiscard]] bool empty() const ENTT_NOEXCEPT {
|
|
return !*this || !*length;
|
|
}
|
|
|
|
/**
|
|
* @brief 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()`.
|
|
*
|
|
* @return An iterator to the first entity of the group.
|
|
*/
|
|
[[nodiscard]] iterator begin() const ENTT_NOEXCEPT {
|
|
return *this ? (std::get<0>(pools)->base_type::end() - *length) : iterator{};
|
|
}
|
|
|
|
/**
|
|
* @brief 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.
|
|
*
|
|
* @return An iterator to the entity following the last entity of the
|
|
* group.
|
|
*/
|
|
[[nodiscard]] iterator end() const ENTT_NOEXCEPT {
|
|
return *this ? std::get<0>(pools)->base_type::end() : iterator{};
|
|
}
|
|
|
|
/**
|
|
* @brief 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()`.
|
|
*
|
|
* @return An iterator to the first entity of the reversed group.
|
|
*/
|
|
[[nodiscard]] reverse_iterator rbegin() const ENTT_NOEXCEPT {
|
|
return *this ? std::get<0>(pools)->base_type::rbegin() : reverse_iterator{};
|
|
}
|
|
|
|
/**
|
|
* @brief 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.
|
|
*
|
|
* @return An iterator to the entity following the last entity of the
|
|
* reversed group.
|
|
*/
|
|
[[nodiscard]] reverse_iterator rend() const ENTT_NOEXCEPT {
|
|
return *this ? (std::get<0>(pools)->base_type::rbegin() + *length) : reverse_iterator{};
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the first entity of the group, if any.
|
|
* @return The first entity of the group if one exists, the null entity
|
|
* otherwise.
|
|
*/
|
|
[[nodiscard]] entity_type front() const ENTT_NOEXCEPT {
|
|
const auto it = begin();
|
|
return it != end() ? *it : null;
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the last entity of the group, if any.
|
|
* @return The last entity of the group if one exists, the null entity
|
|
* otherwise.
|
|
*/
|
|
[[nodiscard]] entity_type back() const ENTT_NOEXCEPT {
|
|
const auto it = rbegin();
|
|
return it != rend() ? *it : null;
|
|
}
|
|
|
|
/**
|
|
* @brief Finds an entity.
|
|
* @param entt A valid identifier.
|
|
* @return An iterator to the given entity if it's found, past the end
|
|
* iterator otherwise.
|
|
*/
|
|
[[nodiscard]] iterator find(const entity_type entt) const ENTT_NOEXCEPT {
|
|
const auto it = *this ? std::get<0>(pools)->find(entt) : iterator{};
|
|
return it != end() && it >= begin() && *it == entt ? it : end();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the identifier that occupies the given position.
|
|
* @param pos Position of the element to return.
|
|
* @return The identifier that occupies the given position.
|
|
*/
|
|
[[nodiscard]] entity_type operator[](const size_type pos) const {
|
|
return begin()[pos];
|
|
}
|
|
|
|
/**
|
|
* @brief Checks if a group is properly initialized.
|
|
* @return True if the group is properly initialized, false otherwise.
|
|
*/
|
|
[[nodiscard]] explicit operator bool() const ENTT_NOEXCEPT {
|
|
return length != nullptr;
|
|
}
|
|
|
|
/**
|
|
* @brief Checks if a group contains an entity.
|
|
* @param entt A valid identifier.
|
|
* @return True if the group contains the given entity, false otherwise.
|
|
*/
|
|
[[nodiscard]] bool contains(const entity_type entt) const ENTT_NOEXCEPT {
|
|
return *this && std::get<0>(pools)->contains(entt) && (std::get<0>(pools)->index(entt) < (*length));
|
|
}
|
|
|
|
/**
|
|
* @brief 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.
|
|
*
|
|
* @tparam Comp Types of components to get.
|
|
* @param entt A valid identifier.
|
|
* @return The components assigned to the entity.
|
|
*/
|
|
template<typename... Comp>
|
|
[[nodiscard]] decltype(auto) get(const entity_type entt) const {
|
|
ENTT_ASSERT(contains(entt), "Group does not contain entity");
|
|
|
|
if constexpr(sizeof...(Comp) == 0) {
|
|
return std::tuple_cat(std::get<storage_type<Owned> *>(pools)->get_as_tuple(entt)..., std::get<storage_type<Get> *>(pools)->get_as_tuple(entt)...);
|
|
} else if constexpr(sizeof...(Comp) == 1) {
|
|
return (std::get<storage_type<Comp> *>(pools)->get(entt), ...);
|
|
} else {
|
|
return std::tuple_cat(std::get<storage_type<Comp> *>(pools)->get_as_tuple(entt)...);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief 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.<br/>
|
|
* The signature of the function must be equivalent to one of the following
|
|
* forms:
|
|
*
|
|
* @code{.cpp}
|
|
* void(const entity_type, Type &...);
|
|
* void(Type &...);
|
|
* @endcode
|
|
*
|
|
* @note
|
|
* Empty types aren't explicitly instantiated and therefore they are never
|
|
* returned during iterations.
|
|
*
|
|
* @tparam Func Type of the function object to invoke.
|
|
* @param func A valid function object.
|
|
*/
|
|
template<typename Func>
|
|
void each(Func func) const {
|
|
for(auto args: each()) {
|
|
if constexpr(is_applicable_v<Func, decltype(std::tuple_cat(std::tuple<entity_type>{}, std::declval<basic_group>().get({})))>) {
|
|
std::apply(func, args);
|
|
} else {
|
|
std::apply([&func](auto, auto &&...less) { func(std::forward<decltype(less)>(less)...); }, args);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Returns an iterable object to use to _visit_ a 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.
|
|
*
|
|
* @return An iterable object to use to _visit_ the group.
|
|
*/
|
|
[[nodiscard]] iterable each() const ENTT_NOEXCEPT {
|
|
iterator last = length ? std::get<0>(pools)->basic_common_type::end() : iterator{};
|
|
return {extended_group_iterator{last - *length, pools}, extended_group_iterator{last, pools}};
|
|
}
|
|
|
|
/**
|
|
* @brief 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:
|
|
*
|
|
* @code{.cpp}
|
|
* bool(std::tuple<Component &...>, std::tuple<Component &...>);
|
|
* bool(const Component &, const Component &);
|
|
* bool(const Entity, const Entity);
|
|
* @endcode
|
|
*
|
|
* Where `Component` are either owned types or not but still such that they
|
|
* are iterated by the group.<br/>
|
|
* Moreover, the comparison function object shall induce a
|
|
* _strict weak ordering_ on the values.
|
|
*
|
|
* The sort function object 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.
|
|
*
|
|
* @tparam Comp Optional types of components to compare.
|
|
* @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... Comp, typename Compare, typename Sort = std_sort, typename... Args>
|
|
void sort(Compare compare, Sort algo = Sort{}, Args &&...args) const {
|
|
auto *cpool = std::get<0>(pools);
|
|
|
|
if constexpr(sizeof...(Comp) == 0) {
|
|
static_assert(std::is_invocable_v<Compare, const entity_type, const entity_type>, "Invalid comparison function");
|
|
cpool->sort_n(*length, std::move(compare), std::move(algo), std::forward<Args>(args)...);
|
|
} else {
|
|
auto comp = [this, &compare](const entity_type lhs, const entity_type rhs) {
|
|
if constexpr(sizeof...(Comp) == 1) {
|
|
return compare((std::get<storage_type<Comp> *>(pools)->get(lhs), ...), (std::get<storage_type<Comp> *>(pools)->get(rhs), ...));
|
|
} else {
|
|
return compare(std::forward_as_tuple(std::get<storage_type<Comp> *>(pools)->get(lhs)...), std::forward_as_tuple(std::get<storage_type<Comp> *>(pools)->get(rhs)...));
|
|
}
|
|
};
|
|
|
|
cpool->sort_n(*length, std::move(comp), std::move(algo), std::forward<Args>(args)...);
|
|
}
|
|
|
|
[this](auto *head, auto *...other) {
|
|
for(auto next = *length; next; --next) {
|
|
const auto pos = next - 1;
|
|
[[maybe_unused]] const auto entt = head->data()[pos];
|
|
(other->swap_elements(other->data()[pos], entt), ...);
|
|
}
|
|
}(std::get<storage_type<Owned> *>(pools)...);
|
|
}
|
|
|
|
private:
|
|
const std::tuple<storage_type<Owned> *..., storage_type<Get> *...> pools;
|
|
const size_type *const length;
|
|
};
|
|
|
|
} // namespace entt
|
|
|
|
#endif
|