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36 lines
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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Operation to map all contained `Entity` fields in a type to new values."><title>MapEntities in bevy_ecs::entity - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-42caa33d.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="bevy_ecs" data-themes="" data-resource-suffix="" data-rustdoc-version="1.84.0 (9fc6b4312 2025-01-07)" data-channel="1.84.0" data-search-js="search-92e6798f.js" data-settings-js="settings-0f613d39.js" ><script src="../../static.files/storage-59e33391.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-5f194d8c.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-893ab5e7.css"></noscript><link rel="icon" href="https://bevyengine.org/assets/icon.png"></head><body class="rustdoc trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle" title="show sidebar"></button><a class="logo-container" href="../../bevy_ecs/index.html"><img src="https://bevyengine.org/assets/icon.png" alt=""></a></nav><nav class="sidebar"><div class="sidebar-crate"><a class="logo-container" href="../../bevy_ecs/index.html"><img src="https://bevyengine.org/assets/icon.png" alt="logo"></a><h2><a href="../../bevy_ecs/index.html">bevy_<wbr>ecs</a><span class="version">0.15.1</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">MapEntities</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#example" title="Example">Example</a></li></ul><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.map_entities" title="map_entities">map_entities</a></li></ul><h3><a href="#dyn-compatibility">Dyn Compatibility</a></h3><h3><a href="#implementors">Implementors</a></h3></section><div id="rustdoc-modnav"><h2><a href="index.html">In bevy_<wbr>ecs::<wbr>entity</a></h2></div></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><span class="rustdoc-breadcrumbs"><a href="../index.html">bevy_ecs</a>::<wbr><a href="index.html">entity</a></span><h1>Trait <span class="trait">MapEntities</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../../src/bevy_ecs/entity/map_entities.rs.html#47-53">Source</a> </span></div><pre class="rust item-decl"><code>pub trait MapEntities {
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// Required method
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fn <a href="#tymethod.map_entities" class="fn">map_entities</a><M: <a class="trait" href="trait.EntityMapper.html" title="trait bevy_ecs::entity::EntityMapper">EntityMapper</a>>(&mut self, entity_mapper: <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&mut M</a>);
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}</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Operation to map all contained <a href="struct.Entity.html" title="struct bevy_ecs::entity::Entity"><code>Entity</code></a> fields in a type to new values.</p>
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<p>As entity IDs are valid only for the <a href="../world/struct.World.html" title="struct bevy_ecs::world::World"><code>World</code></a> they’re sourced from, using <a href="struct.Entity.html" title="struct bevy_ecs::entity::Entity"><code>Entity</code></a>
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as references in components copied from another world will be invalid. This trait
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allows defining custom mappings for these references via <a href="trait.EntityMapper.html" title="trait bevy_ecs::entity::EntityMapper"><code>EntityMappers</code></a>, which
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inject the entity mapping strategy between your <code>MapEntities</code> type and the current world
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(usually by using an <a href="type.EntityHashMap.html" title="type bevy_ecs::entity::EntityHashMap"><code>EntityHashMap<Entity></code></a> between source entities and entities in the
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current world).</p>
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<p>This trait is similar to <a href="trait.VisitEntitiesMut.html" title="trait bevy_ecs::entity::VisitEntitiesMut"><code>VisitEntitiesMut</code></a>. They differ in that <a href="trait.VisitEntitiesMut.html" title="trait bevy_ecs::entity::VisitEntitiesMut"><code>VisitEntitiesMut</code></a> operates
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on <code>&mut Entity</code> and allows for in-place modification, while this trait makes no assumption that
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such in-place modification is occurring, which is impossible for types such as <a href="../../bevy_utils/type.HashSet.html" title="type bevy_utils::HashSet"><code>HashSet<Entity></code></a>
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and <a href="type.EntityHashMap.html" title="type bevy_ecs::entity::EntityHashMap"><code>EntityHashMap</code></a> which must be rebuilt when their contained <a href="struct.Entity.html" title="struct bevy_ecs::entity::Entity"><code>Entity</code></a>s are remapped.</p>
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<p>Implementing this trait correctly is required for properly loading components
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with entity references from scenes.</p>
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<h3 id="example"><a class="doc-anchor" href="#example">§</a>Example</h3>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>bevy_ecs::prelude::<span class="kw-2">*</span>;
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<span class="kw">use </span>bevy_ecs::entity::MapEntities;
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<span class="attr">#[derive(Component)]
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</span><span class="kw">struct </span>Spring {
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a: Entity,
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b: Entity,
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}
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<span class="kw">impl </span>MapEntities <span class="kw">for </span>Spring {
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<span class="kw">fn </span>map_entities<M: EntityMapper>(<span class="kw-2">&mut </span><span class="self">self</span>, entity_mapper: <span class="kw-2">&mut </span>M) {
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<span class="self">self</span>.a = entity_mapper.map_entity(<span class="self">self</span>.a);
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<span class="self">self</span>.b = entity_mapper.map_entity(<span class="self">self</span>.b);
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}
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}</code></pre></div>
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</div></details><h2 id="required-methods" class="section-header">Required Methods<a href="#required-methods" class="anchor">§</a></h2><div class="methods"><details class="toggle method-toggle" open><summary><section id="tymethod.map_entities" class="method"><a class="src rightside" href="../../src/bevy_ecs/entity/map_entities.rs.html#52">Source</a><h4 class="code-header">fn <a href="#tymethod.map_entities" class="fn">map_entities</a><M: <a class="trait" href="trait.EntityMapper.html" title="trait bevy_ecs::entity::EntityMapper">EntityMapper</a>>(&mut self, entity_mapper: <a class="primitive" href="https://doc.rust-lang.org/1.84.0/std/primitive.reference.html">&mut M</a>)</h4></section></summary><div class="docblock"><p>Updates all <a href="struct.Entity.html" title="struct bevy_ecs::entity::Entity"><code>Entity</code></a> references stored inside using <code>entity_mapper</code>.</p>
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<p>Implementors should look up any and all <a href="struct.Entity.html" title="struct bevy_ecs::entity::Entity"><code>Entity</code></a> values stored within <code>self</code> and
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update them to the mapped values via <code>entity_mapper</code>.</p>
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</div></details></div><h2 id="dyn-compatibility" class="section-header">Dyn Compatibility<a href="#dyn-compatibility" class="anchor">§</a></h2><div class="dyn-compatibility-info"><p>This trait is <b>not</b> <a href="https://doc.rust-lang.org/1.84.0/reference/items/traits.html#object-safety">dyn compatible</a>.</p><p><i>In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.</i></p></div><h2 id="implementors" class="section-header">Implementors<a href="#implementors" class="anchor">§</a></h2><div id="implementors-list"><section id="impl-MapEntities-for-T" class="impl"><a class="src rightside" href="../../src/bevy_ecs/entity/map_entities.rs.html#55-61">Source</a><a href="#impl-MapEntities-for-T" class="anchor">§</a><h3 class="code-header">impl<T: <a class="trait" href="trait.VisitEntitiesMut.html" title="trait bevy_ecs::entity::VisitEntitiesMut">VisitEntitiesMut</a>> <a class="trait" href="trait.MapEntities.html" title="trait bevy_ecs::entity::MapEntities">MapEntities</a> for T</h3></section></div><script src="../../trait.impl/bevy_ecs/entity/map_entities/trait.MapEntities.js" async></script></section></div></main></body></html> |