crates/border-wars/src/camera.rs

@@ -46,7 +46,11 @@ impl Plugin for CameraPlugin {
     fn build(&self, app: &mut App) {
         app.add_systems(Startup, init_camera)
             .add_systems(Startup, init_resources_for_camera)
-            .add_systems(Update, movement_system.run_if(in_state(CurrentScene::Game)))
+            .add_systems(
+                Update,
+                (keyboard_movement_system, mouse_movement_system)
+                    .run_if(in_state(CurrentScene::Game)),
+            )
             .add_systems(Update, scale_system.run_if(in_state(CurrentScene::Game)));
     }
 }
@@ -78,7 +82,7 @@ fn init_resources_for_camera(mut commands: Commands) {
 }
 
 /// Moves the camera with keyboard input.
-fn movement_system(
+fn keyboard_movement_system(
     mut query: Query<&mut Transform, With<Camera>>,
     keys: Res<Input<KeyCode>>,
     keys_settings: Res<KeysMovementSettings>,
@@ -100,6 +104,35 @@ fn movement_system(
     }
 }
 
+/// Moves the camera with mouse input.
+fn mouse_movement_system(
+    mouse_button_input: Res<Input<MouseButton>>,
+    mut query: Query<&mut Transform, With<Camera>>,
+    windows: Query<&Window>,
+    mut last_position: Local<Option<Vec2>>,
+) {
+    let window = windows.get_single().expect("Main window not found");
+    let Some(position) = window.cursor_position() else {
+        return;
+    };
+
+    if mouse_button_input.just_pressed(MouseButton::Right) {
+        *last_position = Some(position);
+    }
+
+    if mouse_button_input.just_released(MouseButton::Right) {
+        *last_position = None;
+    }
+
+    if let Some(old_position) = *last_position {
+        for mut transform in query.iter_mut() {
+            let offset = (old_position - position).extend(0.0) * Vec3::new(1., -1., 1.);
+            transform.translation += offset;
+        }
+        *last_position = Some(position);
+    }
+}
+
 /// Scales the view with mouse input.
 fn scale_system(
     mut scroll_event: EventReader<MouseWheel>,

crates/border-wars/src/lib.rs

@@ -8,8 +8,8 @@ use serde::{Deserialize, Serialize};
 pub mod camera;
 pub mod map;
 pub mod networking;
-pub mod responsive_scale;
 pub mod scenes;
+pub mod ui;
 
 /// The current scene of the game.
 #[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Hash, States)]

crates/border-wars/src/main.rs

@@ -7,6 +7,7 @@ use border_wars::map::renderer::RendererPlugin;
 use border_wars::map::selected_tile::SelectTilePlugin;
 use border_wars::networking::NetworkingPlugin;
 use border_wars::scenes::ScenesPlugin;
+use border_wars::ui::UiPlugin;
 
 fn main() {
     App::new()
@@ -17,5 +18,6 @@ fn main() {
         .add_plugins(SelectTilePlugin)
         .add_plugins(NetworkingPlugin)
         .add_plugins(MapGenerationPlugin)
+        .add_plugins(UiPlugin)
         .run();
 }

crates/border-wars/src/scenes/mod.rs

@@ -3,7 +3,7 @@
 use bevy::prelude::*;
 use bevy_egui::EguiPlugin;
 
-use crate::{responsive_scale, CurrentScene};
+use crate::CurrentScene;
 
 pub mod lobby;
 pub mod menu;
@@ -16,7 +16,6 @@ impl Plugin for ScenesPlugin {
         app.add_plugins(EguiPlugin)
             .add_state::<CurrentScene>()
             .add_plugins(menu::MenuPlugin)
-            .add_plugins(lobby::LobbyPlugin)
-            .add_plugins(responsive_scale::ResponsiveScalingPlugin);
+            .add_plugins(lobby::LobbyPlugin);
     }
 }

crates/border-wars/src/ui/hover.rs

@@ -0,0 +1,38 @@
+//! The file that contains the hover logic.
+
+use bevy::prelude::*;
+
+/// The plugin for the hover system.
+pub struct HoverPlugin;
+
+impl Plugin for HoverPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Update, hovering);
+    }
+}
+
+/// A component that stores the hover texture and the original texture.
+#[derive(Component, Clone)]
+struct HoveredTexture {
+    /// The original texture.
+    texture: Handle<Image>,
+
+    /// The hovered texture.
+    hovered_texture: Handle<Image>,
+}
+
+/// The system that applies the hover logic by changing the texture.
+fn hovering(
+    mut interaction_query: Query<
+        (&Interaction, &HoveredTexture, &mut UiImage),
+        Changed<Interaction>,
+    >,
+) {
+    for (interaction, textures, mut image) in interaction_query.iter_mut() {
+        match *interaction {
+            Interaction::Hovered => image.texture = textures.hovered_texture.clone(),
+            Interaction::None => image.texture = textures.texture.clone(),
+            Interaction::Pressed => (),
+        }
+    }
+}

crates/border-wars/src/ui/mod.rs

@@ -0,0 +1,19 @@
+//! The file that contains the UI logic.
+
+pub mod hover;
+pub mod responsive_scale;
+
+use bevy::prelude::*;
+
+use self::hover::HoverPlugin;
+use self::responsive_scale::ResponsiveScalingPlugin;
+
+/// The plugin for the UI.
+pub struct UiPlugin;
+
+impl Plugin for UiPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_plugins(HoverPlugin)
+            .add_plugins(ResponsiveScalingPlugin);
+    }
+}

crates/border-wars/src/ui/responsive_scale.rs

@@ -29,6 +29,9 @@ pub fn change_scaling(
     size: Res<UILayoutSize>,
 ) {
     let window = windows.get_single().expect("Main window not found");
+    if window.resolution.physical_height() == 0 {
+        return;
+    };
     let (a, b) = (
         window.resolution.width() / size.0.x,
         window.resolution.height() / size.0.y,