engine/examples/simple_window/src/main.rs

use anyhow::Result;

use ecs::*;
use engine::prelude::*;

fn main() -> Result<()> {
    let mut world_builder = World::builder();

    Engine::new::<GameState>(EngineCreateInfo::default(), &mut world_builder)?;

    world_builder.add_system(GameState::update);
    world_builder.resources.insert(GameState::Startup);

    world_builder.build().run()
}

enum GameState {
    Startup,
    Loading,
    Menu,
    Game(Game),
}

impl GameState {
    fn update(world: &mut World) -> Result<bool> {
        match world.resources.get_mut_unchecked::<Self>() {
            GameState::Startup => (),
            GameState::Loading => (),
            GameState::Menu => (),
            GameState::Game(game) => game.update(world)?,
        }

        Ok(true)
    }
}

impl EventConsumer for GameState {
    fn event(&mut self, world: &mut World, event: EngineEvent) -> Result<()> {
        match self {
            GameState::Startup => (),
            GameState::Loading => (),
            GameState::Menu => (),
            GameState::Game(game) => game.event(world, event)?,
        }

        Ok(())
    }
}

struct Game {}

impl Game {
    fn update(&mut self, world: &mut World) -> Result<()> {
        Ok(())
    }

    fn event(&mut self, world: &mut World, event: EngineEvent) -> Result<()> {
        Ok(())
    }
}