statez 0.1.2

Basic state management for the ggez game framework.
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extern crate ggez;
extern crate statez;

use ggez::{conf, event, graphics, Context, GameResult};
use statez::{State, StateManager, StateTransition};

#[derive(Default)]
struct SharedData; // empty

#[derive(Default)]
struct StateOne {
    go_to_next_state: bool,
}

#[derive(Default)]
struct StateTwo {
    go_to_next_state: bool,
}

impl State<SharedData> for StateOne {
    fn update(
        &mut self,
        _shared_data: &mut SharedData,
        _ctx: &mut Context,
    ) -> GameResult<StateTransition<SharedData>> {
        if self.go_to_next_state {
            Ok(StateTransition::Replace(Box::new(StateTwo::default())))
        } else {
            Ok(StateTransition::None)
        }
    }

    fn draw(&mut self, _shared_data: &mut SharedData, ctx: &mut Context) -> GameResult<()> {
        graphics::set_background_color(ctx, graphics::WHITE);
        graphics::clear(ctx);
        graphics::present(ctx);

        Ok(())
    }

    fn key_up_event(
        &mut self,
        _shared_data: &mut SharedData,
        _ctx: &mut Context,
        keycode: event::Keycode,
        _keymod: event::Mod,
        _repeat: bool,
    ) {
        if keycode == event::Keycode::Space {
            self.go_to_next_state = true;
        }
    }
}

impl State<SharedData> for StateTwo {
    fn update(
        &mut self,
        _shared_data: &mut SharedData,
        _ctx: &mut Context,
    ) -> GameResult<StateTransition<SharedData>> {
        if self.go_to_next_state {
            Ok(StateTransition::Replace(Box::new(StateOne::default())))
        } else {
            Ok(StateTransition::None)
        }
    }

    fn draw(&mut self, _shared_data: &mut SharedData, ctx: &mut Context) -> GameResult<()> {
        graphics::set_background_color(ctx, graphics::BLACK);
        graphics::clear(ctx);
        graphics::present(ctx);

        Ok(())
    }

    fn key_up_event(
        &mut self,
        _shared_data: &mut SharedData,
        _ctx: &mut Context,
        keycode: event::Keycode,
        _keymod: event::Mod,
        _repeat: bool,
    ) {
        if keycode == event::Keycode::Space {
            self.go_to_next_state = true;
        }
    }
}

fn main() {
    let mut conf = conf::Conf::new();
    conf.window_setup =
        conf::WindowSetup::default().title("statez - hello_world - press space to swap state");
    let ctx = &mut Context::load_from_conf("hello_world", "statez", conf)
        .expect("Unable to create context");

    let shared_data = SharedData::default();
    let state_manager = &mut StateManager::new(shared_data, Box::new(StateOne::default()));

    event::run(ctx, state_manager).expect("Fatal error");

    println!("Terminated successfully.");
}