use unwrap

src/main.rs

@@ -3,5 +3,53 @@ use bevy::prelude::*;
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
+        .add_systems(Startup, spawn_player)
+        .add_systems(Startup, spawn_camera)
+        .add_systems(Main, move_player)
         .run();
-}
+}
+
+const PLAYER_SPEED: f32 = 500.0;
+
+#[derive(Component)]
+struct Player;
+
+fn spawn_player(mut commands: Commands, asset_server: Res<AssetServer>) {
+    commands.spawn((
+        Player,
+        SpriteBundle {
+            texture: asset_server.load("sprites/human.png"),
+            ..Default::default()
+        },
+    ));
+}
+
+fn move_player(
+    key: Res<ButtonInput<KeyCode>>,
+    time: Res<Time>,
+    mut q_player: Query<&mut Transform, With<Player>>,
+) {
+    let mut direction = Vec3::ZERO;
+    if key.pressed(KeyCode::KeyW) {
+        direction.y += 1.0;
+    }
+    if key.pressed(KeyCode::KeyS) {
+        direction.y -= 1.0;
+    }
+    if key.pressed(KeyCode::KeyD) {
+        direction.x += 1.0;
+    }
+    if key.pressed(KeyCode::KeyA) {
+        direction.x -= 1.0;
+    }
+    if direction != Vec3::ZERO {
+        let mut player_transform = q_player.get_single_mut().unwrap();
+        player_transform.translation += direction.normalize() * PLAYER_SPEED * time.delta_seconds();
+    }
+}
+
+fn spawn_camera(mut commands: Commands) {
+    commands.spawn(Camera2dBundle {
+        ..Default::default()
+    });
+}