djeedai / bevy_hanabi / 27069487078

58%

Build Type

push

github

Committed by web-flow

Commit Message

Serialization through Bevy's type registry (#534)

This change transitions from the `typetag` dependency to using Bevy's
own built-in `TypeRegistry` to serialize and deserialize Hanabi's
`EffectAsset` (`*.effect`).

This solves a long-standing issue where modifiers couldn't be serialized
easily, and user-provided modifiers were ignored for serialization. With
the use of Bevy's own type registry, all built-in and user modifiers are
treated equally, as long as they are registered via
`register_reflect_modifier()`. All built-in modifiers are automatically
registered by the `HanabiPlugin`.

That registration allows leveraging the new `ReflectModifier` type data,
which provides a factory function to create a concrete modifier type
instance.  This is used during deserialization to instantiate the actual
modifier object.  This works around the lack of reflection/serialization
support for `Box<dyn Trait>`.

This change has a few knock-on effects on other parts of Hanabi:
- `EffectAsset::mesh` is now an `Option<AssetPath<'static>>` referencing
  the mesh, if any, used to render particles. That path is now also
  serialized.
- At runtime, the new `EffectMesh` component can override this asset
  mesh.

With this, `EffectAsset` is now entirely serializable. This doesn't
solve the entire asset story, as some additional items are still missing
(notably, textures). But this should greatly improve the value
proposition for loading Hanabi effects from assets on disk, rather than
generating effects in code.

Coverage Stats

280 of 410 new or added lines in 6 files covered. (68.29%)

8 existing lines in 2 files now uncovered.

5121 of 8760 relevant lines covered (58.46%)

190.98 hits per line