ADR-82: Mesh name of pointer events for GLTF in ECS7

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Latest published version:
https://adr.decentraland.org/adr/ADR-82
Authors:
gonpombo8
kuruk-mm
leanmendoza
menduz
nearnshaw
pbosio
pravusjif
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Context of the problem

In ECS6 the pointer events of GLTF have a meshName: string field that works for all meshes, that is because the raycasts for the clicks intersected all meshes in the GLTF.

In the new version of the ECS, the GltfContainer component have different semantics. Only meshes postfixed with _collider will be intersectable by raycasts.

The question that we are evaluating in this ADR is: "Which mesh name is going to be sent back to the scene?"

A key consideration must be the compatibility with ECS6 for all the time the adaptation layer lives. The adaptation layer should effortlessly mock the same behavior of the ECS6.

Alternatives

Alternative 1

Send the name of the collider mesh in the raycast event. This option would require explicit colliders. The name of the field will be hitName: string.

This is different to ECS6 because if no colliders are present in the GLTF, the loader automatically assigns the visible meshes to the collider, inheriting the name of the real meshes for the raycast.

Alterlative 1.bis ✅

Send the name of the collider mesh in the raycast event. This option would require explicit colliders. The name of the field will be hitName: string

To surround the compatibility problem with ECS6, a new GltfContainerCompatibility component can be created to mock the same behavior of the ECS6. This component would be hidden to the end-user to only be used by the Adaptation Layer.

Alternative 2

Add a new EntityName(name: string) component to any entity, and in each raycast hit bubble up until an entity has a EntityName(name: string) and use that one for the event.

Implementation: For entities created by the user, EntityName(name: string) should be manually added.

For the GltfContainer, the name of the parent node will be considered and added to the internal entity of the GltfScene.

Open questions

License

Copyright and related rights waived via CC0-1.0. DRAFT Draft