Draw crosshair when cursor grabbed

src/free_camera.rs

@@ -33,20 +33,24 @@ impl Default for CameraFreeLook {
 }
 
 pub fn camera_free_look(
-    window: Single<(&Window, &mut CursorOptions)>,
     accumulated_mouse_motion: Res<AccumulatedMouseMotion>,
     mouse_button_input: Res<ButtonInput<MouseButton>>,
     key_input: Res<ButtonInput<KeyCode>>,
+    window: Single<(&Window, &mut CursorOptions)>,
     camera: Single<(&mut Transform, &mut CameraFreeLook)>,
+    crosshair: Single<&mut Visibility, With<Crosshair>>,
 ) {
     let (window, mut cursor) = window.into_inner();
     let (mut transform, mut look) = camera.into_inner();
+    let mut crosshair_visibility = crosshair.into_inner();
 
     if !window.focused || key_input.just_pressed(KeyCode::Escape) {
+        *crosshair_visibility = Visibility::Hidden;
         cursor.grab_mode = CursorGrabMode::None;
         cursor.visible = true;
     }
     if mouse_button_input.any_just_pressed([MouseButton::Left, MouseButton::Right]) {
+        *crosshair_visibility = Visibility::Inherited;
         cursor.grab_mode = CursorGrabMode::Locked;
         cursor.visible = false;
     }
@@ -139,3 +143,32 @@ pub fn noclip_controller(
         transform.translation += movement.z * dt * forward;
     }
 }
+
+#[derive(Component)]
+pub struct Crosshair;
+
+pub fn setup_crosshair(mut commands: Commands, asset_server: Res<AssetServer>) {
+    commands.spawn((
+        Node {
+            width: percent(100),
+            height: percent(100),
+            align_items: AlignItems::Center,
+            justify_content: JustifyContent::Center,
+            ..default()
+        },
+        children![(
+            Crosshair,
+            Node {
+                width: px(64),
+                height: px(64),
+                ..default()
+            },
+            ImageNode {
+                image: asset_server.load("crosshair.png"),
+                ..default()
+            },
+            // Hidden by default, because cursor shouldn't be grabbed at startup either.
+            Visibility::Hidden,
+        )],
+    ));
+}

src/main.rs

@@ -9,7 +9,7 @@ use placement::*;
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
-        .add_systems(Startup, setup)
+        .add_systems(Startup, (setup_scene, setup_crosshair))
         .add_systems(Update, (camera_free_look, noclip_controller).chain())
         // This system requires `GlobalTransform`, so for a most
         // up-to-date value, run it right after it's been updated.
@@ -20,7 +20,7 @@ fn main() {
         .run();
 }
 
-fn setup(
+fn setup_scene(
     mut commands: Commands,
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<StandardMaterial>>,