godot::prelude

Derive Macro GodotConvert

#[derive(GodotConvert)]
{
    // Attributes available to this derive:
    #[godot]
}
Expand description

Derive macro for GodotConvert on structs.

This derive macro also derives ToGodot and FromGodot.

§Choosing a Via type

To specify the Via type that your type should be converted to, you must use the godot attribute. There are currently two modes supported.

§transparent

If you specify #[godot(transparent)] on single-field struct, your struct will be treated as a newtype struct. This means that all derived operations on the struct will defer to the type of that single field.

§Example

use godot::prelude::*;

#[derive(GodotConvert)]
#[godot(transparent)]
struct CustomVector2(Vector2);

let obj = CustomVector2(Vector2::new(10.0, 25.0));
assert_eq!(obj.to_godot(), Vector2::new(10.0, 25.0));

This also works for named structs with a single field:

use godot::prelude::*;

#[derive(GodotConvert)]
#[godot(transparent)]
struct MyNewtype {
    string: GString,
}

let obj = MyNewtype {
    string: "hello!".into(),
};
assert_eq!(obj.to_godot(), GString::from("hello!"));

However, it will not work for structs with more than one field, even if that field is zero sized:

use godot::prelude::*;

#[derive(GodotConvert)]
#[godot(transparent)]
struct SomeNewtype {
    int: i64,
    zst: (),
}

You can also not use transparent with enums:

use godot::prelude::*;

#[derive(GodotConvert)]
#[godot(transparent)]
enum MyEnum {
    Int(i64)
}

§via = <type>

For c-style enums, that is enums where all the variants are unit-like, you can use via = <type> to convert the enum into that type.

The types you can use this with currently are:

  • GString
  • i8, i16, i32, i64
  • u8, u16, u32

When using one of the integer types, each variant of the enum will be converted into its discriminant.

§Examples

use godot::prelude::*;
#[derive(GodotConvert)]
#[godot(via = GString)]
enum MyEnum {
    A,
    B,
    C,
}

assert_eq!(MyEnum::A.to_godot(), GString::from("A"));
assert_eq!(MyEnum::B.to_godot(), GString::from("B"));
assert_eq!(MyEnum::C.to_godot(), GString::from("C"));
use godot::prelude::*;
#[derive(GodotConvert)]
#[godot(via = i64)]
enum MyEnum {
    A,
    B,
    C,
}

assert_eq!(MyEnum::A.to_godot(), 0);
assert_eq!(MyEnum::B.to_godot(), 1);
assert_eq!(MyEnum::C.to_godot(), 2);

Explicit discriminants are used for integers:

use godot::prelude::*;
#[derive(GodotConvert)]
#[godot(via = u8)]
enum MyEnum {
    A,
    B = 10,
    C,
}

assert_eq!(MyEnum::A.to_godot(), 0);
assert_eq!(MyEnum::B.to_godot(), 10);
assert_eq!(MyEnum::C.to_godot(), 11);