bevy_proto_backend/schematics/
schematic.rs

1use bevy::prelude::{FromReflect, Reflect};
2use bevy::reflect::{GetTypeRegistration, Typed};
3
4use crate::deps::DependenciesBuilder;
5use crate::schematics::SchematicContext;
6
7/// Trait used to create a [prototype] schematic for modifying an [entity]
8/// (or the [world] in general).
9///
10/// This trait can either be manually implemented or [derived].
11///
12/// See the [module-level documentation] for details.
13///
14/// # Example
15///
16/// ```
17/// use bevy::prelude::{Component, Reflect};
18/// use bevy_proto_backend::schematics::{Schematic, SchematicContext};
19/// #[derive(Component, Reflect)]
20/// struct PlayerId(usize);
21///
22/// impl Schematic for PlayerId {
23///   type Input = Self;
24///
25///   fn apply(input: &Self::Input, context: &mut SchematicContext) {
26///     entity.insert(Self(input.0));
27///   }
28///
29///   fn remove(input: &Self::Input, context: &mut SchematicContext) {
30///     entity.remove::<Self>();
31///   }
32/// }
33/// ```
34///
35/// [prototype]: crate::proto::Prototypical
36/// [entity]: bevy::ecs::world::EntityMut
37/// [world]: bevy::ecs::world::World
38/// [derived]: bevy_proto_derive::Schematic
39/// [module-level documentation]: crate::schematics
40pub trait Schematic: Reflect + Typed {
41    /// The input type to this schematic.
42    ///
43    /// This acts as an intermediate between serialized schematic information
44    /// and the actual schematic instance.
45    ///
46    /// For types that don't need an intermediate type, this can just be
47    /// set to `Self`.
48    type Input: FromReflect + GetTypeRegistration;
49
50    /// Controls how this schematic is applied to the given entity.
51    fn apply(input: &Self::Input, context: &mut SchematicContext);
52    /// Controls how this schematic is removed from the given entity.
53    fn remove(input: &Self::Input, context: &mut SchematicContext);
54
55    /// Allows dependency assets to be loaded when this schematic is loaded.
56    #[allow(unused_variables)]
57    fn preload_dependencies(input: &mut Self::Input, dependencies: &mut DependenciesBuilder) {}
58}
59
60/// A custom [`From`]-like trait used to convert the [input] of a [schematic]
61/// to itself.
62///
63/// This is used by [derive macro] to automatically handle the conversion.
64///
65/// This trait is has a blanket implementation for any type where the input
66/// type satisfies [`Into`] for the schematic type.
67///
68/// [input]: Schematic::Input
69/// [schematic]: Schematic
70/// [derive macro]: bevy_proto_derive::Schematic
71pub trait FromSchematicInput<T> {
72    fn from_input(input: T, context: &mut SchematicContext) -> Self;
73}
74
75impl<S, T: Into<S>> FromSchematicInput<T> for S {
76    fn from_input(input: T, _context: &mut SchematicContext) -> S {
77        input.into()
78    }
79}
bevy_proto_backend/schematics/schematic.rs

bevy_proto_backend/schematics/
schematic.rs
