Add GltfMeshName component and Deref implementations (#19331)

Stores mesh names from glTF files in GltfMeshName component rather than
Name component, making both GltfMeshName and GltfMaterialName behave
like strings via Deref.

# Objective

Fixed the side effects of #19287
Fixes Examples that modify gltf materials are broken #19322

## Solution

Add GltfMeshName component and Deref implementations

Stores mesh names from glTF files in GltfMeshName component rather than
Name component, making both GltfMeshName and GltfMaterialName behave
like strings via Deref.


## Testing

cargo run --example depth_of_field
cargo run --example lightmaps
cargo run --example mixed_lighting
They are consistent with the situation before the error occurred.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Rob Parrett <robparrett@gmail.com>

crates/bevy_gltf/src/assets.rs

@@ -1,5 +1,7 @@
 //! Representation of assets present in a glTF file
 
+use core::ops::Deref;
+
 #[cfg(feature = "bevy_animation")]
 use bevy_animation::AnimationClip;
 use bevy_asset::{Asset, Handle};
@@ -297,6 +299,21 @@ pub struct GltfMeshExtras {
     pub value: String,
 }
 
+/// The mesh name of a glTF primitive.
+///
+/// See [the relevant glTF specification section](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-mesh).
+#[derive(Clone, Debug, Reflect, Default, Component)]
+#[reflect(Component, Clone)]
+pub struct GltfMeshName(pub String);
+
+impl Deref for GltfMeshName {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.as_ref()
+    }
+}
+
 /// Additional untyped data that can be present on most glTF types at the material level.
 ///
 /// See [the relevant glTF specification section](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-extras).
@@ -313,3 +330,11 @@ pub struct GltfMaterialExtras {
 #[derive(Clone, Debug, Reflect, Default, Component)]
 #[reflect(Component, Clone)]
 pub struct GltfMaterialName(pub String);
+
+impl Deref for GltfMaterialName {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.as_ref()
+    }
+}

crates/bevy_gltf/src/lib.rs

@@ -193,6 +193,7 @@ impl Plugin for GltfPlugin {
         app.register_type::<GltfExtras>()
             .register_type::<GltfSceneExtras>()
             .register_type::<GltfMeshExtras>()
+            .register_type::<GltfMeshName>()
             .register_type::<GltfMaterialExtras>()
             .register_type::<GltfMaterialName>()
             .init_asset::<Gltf>()

crates/bevy_gltf/src/loader/mod.rs

@@ -66,7 +66,7 @@ use tracing::{error, info_span, warn};
 
 use crate::{
     vertex_attributes::convert_attribute, Gltf, GltfAssetLabel, GltfExtras, GltfMaterialExtras,
-    GltfMaterialName, GltfMeshExtras, GltfNode, GltfSceneExtras, GltfSkin,
+    GltfMaterialName, GltfMeshExtras, GltfMeshName, GltfNode, GltfSceneExtras, GltfSkin,
 };
 
 #[cfg(feature = "bevy_animation")]
@@ -1463,6 +1463,10 @@ fn load_node(
                         });
                     }
 
+                    if let Some(name) = mesh.name() {
+                        mesh_entity.insert(GltfMeshName(name.to_string()));
+                    }
+
                     if let Some(name) = material.name() {
                         mesh_entity.insert(GltfMaterialName(name.to_string()));
                     }

examples/3d/depth_of_field.rs

@@ -15,6 +15,7 @@ use bevy::{
         dof::{self, DepthOfField, DepthOfFieldMode},
         tonemapping::Tonemapping,
     },
+    gltf::GltfMeshName,
     pbr::Lightmap,
     prelude::*,
     render::camera::PhysicalCameraParameters,
@@ -186,7 +187,7 @@ fn tweak_scene(
     mut materials: ResMut<Assets<StandardMaterial>>,
     mut lights: Query<&mut DirectionalLight, Changed<DirectionalLight>>,
     mut named_entities: Query<
-        (Entity, &Name, &MeshMaterial3d<StandardMaterial>),
+        (Entity, &GltfMeshName, &MeshMaterial3d<StandardMaterial>),
         (With<Mesh3d>, Without<Lightmap>),
     >,
 ) {

examples/3d/lightmaps.rs

@@ -3,6 +3,7 @@
 use argh::FromArgs;
 use bevy::{
     core_pipeline::prepass::{DeferredPrepass, DepthPrepass, MotionVectorPrepass},
+    gltf::GltfMeshName,
     pbr::{DefaultOpaqueRendererMethod, Lightmap},
     prelude::*,
 };
@@ -63,7 +64,7 @@ fn add_lightmaps_to_meshes(
     asset_server: Res<AssetServer>,
     mut materials: ResMut<Assets<StandardMaterial>>,
     meshes: Query<
-        (Entity, &Name, &MeshMaterial3d<StandardMaterial>),
+        (Entity, &GltfMeshName, &MeshMaterial3d<StandardMaterial>),
         (With<Mesh3d>, Without<Lightmap>),
     >,
     args: Res<Args>,

examples/3d/mixed_lighting.rs

@@ -1,6 +1,7 @@
 //! Demonstrates how to combine baked and dynamic lighting.
 
 use bevy::{
+    gltf::GltfMeshName,
     pbr::Lightmap,
     picking::{backend::HitData, pointer::PointerInteraction},
     prelude::*,
@@ -221,7 +222,7 @@ fn update_lightmaps(
     mut commands: Commands,
     asset_server: Res<AssetServer>,
     mut materials: ResMut<Assets<StandardMaterial>>,
-    meshes: Query<(Entity, &Name, &MeshMaterial3d<StandardMaterial>), With<Mesh3d>>,
+    meshes: Query<(Entity, &GltfMeshName, &MeshMaterial3d<StandardMaterial>), With<Mesh3d>>,
     mut lighting_mode_change_event_reader: EventReader<LightingModeChanged>,
     app_status: Res<AppStatus>,
 ) {
@@ -432,7 +433,7 @@ fn reset_sphere_position(
 fn move_sphere(
     mouse_button_input: Res<ButtonInput<MouseButton>>,
     pointers: Query<&PointerInteraction>,
-    mut meshes: Query<(&Name, &ChildOf), With<Mesh3d>>,
+    mut meshes: Query<(&GltfMeshName, &ChildOf), With<Mesh3d>>,
     mut transforms: Query<&mut Transform>,
     app_status: Res<AppStatus>,
 ) {

release-content/migration-guides/rename_spawn_gltf_material_name.md

@@ -7,3 +7,5 @@ pull_requests: [19287]
 When loading a Gltf scene in Bevy, each mesh primitive will generate an entity and store a `GltfMaterialName` component and `Name` component.
 
 The `Name` components were previously stored as mesh name plus primitive index - for example, `MeshName.0` and `MeshName.1`. To make it easier to view these entities in Inspector-style tools, they are now stored as mesh name plus material name - for example, `MeshName.Material1Name` and `MeshName.Material2Name`.
+
+If you were relying on the previous value of the `Name` component on meshes, use the new `GltfMeshName` component instead.