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Useful, but I this should just use the standard Bevy Name component. That reduces the code that we have to maintain, and will play nicer with various tooling like bevy_inspector_egui.

I'm also having a hard time figuring out how the example demonstrates the added functionality. Can you explain what you were after? I may be able to suggest how to make things clearer.

Hi Alice, I apologize for the confusion caused by the buggy example query_gltf_primitives. As detailed in the issue #13473, the newly introduced GltfMaterialName component is used to query for a mesh part with the specific material. When multiple materials are assigned to different parts of a mesh, the corresponding primitives are generated in equal number. However, these primitives currently lack individual names.

{
  "meshes": [
    {
      "name": "Cube",
      "primitives": [
        {
          "attributes": { "POSITION": 0, "NORMAL": 1, "TEXCOORD_0": 2 },
          "indices": 3,
          "material": 0
        },
        {
          "attributes": { "POSITION": 4, "NORMAL": 5, "TEXCOORD_0": 6 },
          "indices": 7,
          "material": 1
        },
        {
          "attributes": { "POSITION": 8, "NORMAL": 9, "TEXCOORD_0": 10 },
          "indices": 11,
          "material": 2
        },
        {
          "attributes": { "POSITION": 12, "NORMAL": 13, "TEXCOORD_0": 14 },
          "indices": 15,
          "material": 3
        }
      ]
    }
  ]
}

In bevy, each primitive is named according to its index.

// crates/bevy_gltf/src/loader.rs
fn primitive_name(mesh: &gltf::Mesh, primitive: &Primitive) -> String {
    let mesh_name = mesh.name().unwrap_or("Mesh");
    if mesh.primitives().len() > 1 {
        format!("{}.{}", mesh_name, primitive.index())
    } else {
        mesh_name.to_string()
    }
}

This causes a problem, which is addressed by @MatrixDev in the above issue:

I don't know which primitive contains which material. In case I want to motify some named material, I have to play with scene directly, used entities mapping, it's a boilerplate mess and not ECS friendly.

So it appears useful to name each primitive according to its associated material, given that primitives are distinguished based on the number of materials assigned to a single mesh. However, since some may rely on the indexed names stored in the Name component, I decided to introduce a new naming component for this purpose. This may not be the optimal solution, and I would appreciate your suggestions. Thank you.

I think using 'Name' for everything is not enough. Entity can have a GLTF node/primitive name/index and material name/index all at the same time.

We should be able to query using any of those at any time. Sometimes I want to query for all entities with a specific material, other times I'd like to query for all entities with a specific primitive. Names of materials and primitives might be different.

I'm not even talking about bevy generating names for entites when nodes contain multiple primitives.

Right 🤔 Okay, I see your point. Thank you for explaining!

I have improved the documentation, corrected capitalization errors, and optimized the code of the find_top_material_and_mesh system to achieve smooth color transitions and vertex transformations.

Fantastic, thank you!

Thank you to everyone involved with the authoring or reviewing of this PR! This work is relatively important and needs release notes! Head over to bevyengine/bevy-website#1703 if you'd like to help out.