Persistence API

When making a game or application you will inevitably want to store some kind of state between launches, so that you aren’t starting from scratch each time you run the program. SGE provides a simple high-performance interface to make this easier.

To use the persistence API, create a state struct, and annotate it with the #[persistent] attribute macro.

#![allow(unused)]
fn main() {
#[persistent]
struct State {
    score: u64,
    player_color: Color,
    enemy_state: EnemyState,
}

#[persistent]
struct EnemyState {
    health: f32,
    position: Vec2,
}
}

The persistent macro will generate the functions state.save(path), State::load(path), state.to_bytes(), and State::from_bytes(bytes), for any struct that has fields that are all also serializable.

Serializable types include:

• Most builtin Rust types, numbers, strings, etc.
• Anything supported by rkyv out of the box.
• Most of the SGE types you would want to use this with
  • Vectors
  • Both colour types
• Any other custom struct you write, as long as it is also decorated with #[persistent]

Performance

This uses rkyv under the hood, which performs zero-copy serialization, meaning that it is very fast, so you can save often if you want. Do not save/load every frame.

See Persistent trait

See: /examples/persistence