input.rs

use bevy::prelude::*;
use std::collections::HashSet;

pub struct InputPlugin;

impl Plugin for InputPlugin {
    fn build(&self, app: &mut AppBuilder) {
        app
            .add_startup_system(connection.system())
            .add_system(connection.system())
            .add_system(gamepad_axis.system())
            .add_resource(Lobby::default())
            .add_resource(InputState::default());
    }
}

#[derive(Default)]
struct Lobby {
    gamepad: HashSet<Gamepad>,
    gamepad_event_reader: EventReader<GamepadEvent>,
}

#[derive(Default)]
pub struct InputState {
    pub movement_vector: Vec2,
}

fn connection(mut lobby: ResMut<Lobby>, gamepad_event: Res<Events<GamepadEvent>>) {
    for event in lobby.gamepad_event_reader.iter(&gamepad_event) {
        match &event {
            GamepadEvent(gamepad, GamepadEventType::Connected) => {
                lobby.gamepad.insert(*gamepad);
                println!("Connected {:?}", gamepad);
            }
            GamepadEvent(gamepad, GamepadEventType::Disconnected) => {
                lobby.gamepad.remove(gamepad);
                println!("Disconnected {:?}", gamepad);
            }
        }
    }
}

fn gamepad_axis(
    lobby: Res<Lobby>,
    axes: Res<Axis<GamepadAxis>>,
    mut input: ResMut<InputState>,
) {
    for gamepad in lobby.gamepad.iter() {
        if let Some(value) = axes.get(&GamepadAxis(*gamepad, GamepadAxisType::LeftStickX)) {
            *input.movement_vector.x_mut() = value;
        }
        if let Some(value) = axes.get(&GamepadAxis(*gamepad, GamepadAxisType::LeftStickY)) {
            *input.movement_vector.y_mut() = value;
        }
    }
    if input.movement_vector.length() > 1.0 {
        input.movement_vector = input.movement_vector.normalize()
    }
}

main.rs

use bevy::{
    prelude::*,
    render::pass::ClearColor,
};

mod input;

struct Player;

fn main() {
    App::build()
        .add_resource(ClearColor(Color::rgb(0.5, 0.5, 0.5)))
        .add_resource(WindowDescriptor {
            title: String::from("vshrs"),
            resizable: false,
            ..Default::default()
        })
        .add_default_plugins()
        .add_plugin(input::InputPlugin)
        .add_startup_system(setup.system())
        .add_system(move_player.system())
        .run();
}

fn setup(
    mut commands: Commands,
    mut materials: ResMut<Assets<ColorMaterial>>,
) {
    commands
        .spawn(Camera2dComponents::default())
        .spawn(SpriteComponents {
            material: materials.add(Color::rgb(0.2, 0.2, 0.8).into()),
            transform: Transform::from_translation(Vec3::new(0.0, 0.0, 0.0)),
            sprite: Sprite::new(Vec2::new(25.0, 25.0)),
            ..Default::default()
        })
        .with(Player);
}

fn move_player(
    time: Res<Time>,
    input: Res<input::InputState>,
    _player: &Player,
    mut transform: Mut<Transform>,
) {
    let translation = transform.translation_mut();
    *translation.x_mut() += input.movement_vector.x() * 500.0 * time.delta_seconds;
    *translation.y_mut() += input.movement_vector.y() * 500.0 * time.delta_seconds;
}