Add a camera system (#69)

closes: #63
Reviewed-on: corentin/border-wars#69
Reviewed-by: Tipragot <contact@tipragot.fr>

Cargo.lock

@@ -1317,8 +1317,6 @@ dependencies = [
  "bevy",
  "bevy_egui",
  "noise",
- "num",
- "partial-min-max",
  "paste",
 ]
 
@@ -3019,40 +3017,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "num"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b05180d69e3da0e530ba2a1dae5110317e49e3b7f3d41be227dc5f92e49ee7af"
-dependencies = [
- "num-bigint",
- "num-complex",
- "num-integer",
- "num-iter",
- "num-rational",
- "num-traits",
-]
-
-[[package]]
-name = "num-bigint"
-version = "0.4.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "608e7659b5c3d7cba262d894801b9ec9d00de989e8a82bd4bef91d08da45cdc0"
-dependencies = [
- "autocfg",
- "num-integer",
- "num-traits",
-]
-
-[[package]]
-name = "num-complex"
-version = "0.4.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23c6602fda94a57c990fe0df199a035d83576b496aa29f4e634a8ac6004e68a6"
-dependencies = [
- "num-traits",
-]
-
 [[package]]
 name = "num-derive"
 version = "0.3.3"
@@ -3064,38 +3028,6 @@ dependencies = [
  "syn 1.0.109",
 ]
 
-[[package]]
-name = "num-integer"
-version = "0.1.46"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
-dependencies = [
- "num-traits",
-]
-
-[[package]]
-name = "num-iter"
-version = "0.1.44"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d869c01cc0c455284163fd0092f1f93835385ccab5a98a0dcc497b2f8bf055a9"
-dependencies = [
- "autocfg",
- "num-integer",
- "num-traits",
-]
-
-[[package]]
-name = "num-rational"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0638a1c9d0a3c0914158145bc76cff373a75a627e6ecbfb71cbe6f453a5a19b0"
-dependencies = [
- "autocfg",
- "num-bigint",
- "num-integer",
- "num-traits",
-]
-
 [[package]]
 name = "num-traits"
 version = "0.2.18"
@@ -3353,12 +3285,6 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
-[[package]]
-name = "partial-min-max"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6448add382c60bbbc64f9dab41309a12ec530c05191601042f911356ac09758c"
-
 [[package]]
 name = "paste"
 version = "1.0.14"

crates/border-wars/src/camera.rs

@@ -0,0 +1,123 @@
+//! This module contains the camera systems responsible for movement and
+//! scaling.
+
+use bevy::input::mouse::{MouseScrollUnit, MouseWheel};
+use bevy::prelude::*;
+
+use crate::CurrentScene;
+
+/// The speed of camera movement.
+#[derive(Resource)]
+struct CameraSpeedMouvement(f32);
+
+/// The speed of camera scaling.
+#[derive(Resource)]
+struct CameraSpeedScale(f32);
+
+/// The minimum scale of the camera.
+#[derive(Resource)]
+struct MinimumScale(f32);
+
+/// The maximum scale of the camera.
+#[derive(Resource)]
+struct MaximumScale(f32);
+
+/// Key settings for camera movement.
+#[derive(Resource)]
+pub struct KeysMovementSettings {
+    /// Key to move the camera up.
+    pub up: KeyCode,
+
+    /// Key to move the camera down.
+    pub down: KeyCode,
+
+    /// Key to move the camera right.
+    pub right: KeyCode,
+
+    /// Key to move the camera left.
+    pub left: KeyCode,
+}
+
+/// A Bevy plugin for the camera.
+/// Allows camera movement with the keyboard and scaling with the mouse.
+pub struct CameraPlugin;
+
+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, scale_system.run_if(in_state(CurrentScene::Game)));
+    }
+}
+
+/// Initializes the camera.
+fn init_camera(mut commands: Commands) {
+    commands.spawn(Camera2dBundle::default());
+}
+
+/// Initializes the resources related to the camera.
+///
+/// - [KeysMovementSettings]: The key settings for camera movement.
+/// - [CameraSpeedMouvement]: The speed of camera movement.
+/// - [CameraSpeedScale]: The speed of camera scaling.
+/// - [MinimumScale]: The minimum scale of the camera.
+/// - [MaximumScale]: The maximum scale of the camera.
+fn init_resources_for_camera(mut commands: Commands) {
+    commands.insert_resource(KeysMovementSettings {
+        up: KeyCode::Z,
+        down: KeyCode::S,
+        right: KeyCode::D,
+        left: KeyCode::Q,
+    });
+
+    commands.insert_resource(CameraSpeedMouvement(10.0));
+    commands.insert_resource(CameraSpeedScale(0.1));
+    commands.insert_resource(MinimumScale(0.1));
+    commands.insert_resource(MaximumScale(10.0));
+}
+
+/// Moves the camera with keyboard input.
+fn movement_system(
+    mut query: Query<&mut Transform, With<Camera>>,
+    keys: Res<Input<KeyCode>>,
+    keys_settings: Res<KeysMovementSettings>,
+    movement_speed: Res<CameraSpeedMouvement>,
+) {
+    for mut transform in query.iter_mut() {
+        let mut target = Vec3::ZERO;
+        for key in keys.get_pressed() {
+            match *key {
+                value if value == keys_settings.up => target.y += movement_speed.0,
+                value if value == keys_settings.down => target.y -= movement_speed.0,
+                value if value == keys_settings.right => target.x += movement_speed.0,
+                value if value == keys_settings.left => target.x -= movement_speed.0,
+                _ => continue,
+            }
+        }
+
+        transform.translation += target;
+    }
+}
+
+/// Scales the view with mouse input.
+fn scale_system(
+    mut scroll_event: EventReader<MouseWheel>,
+    mut query: Query<&mut OrthographicProjection, With<Camera>>,
+    min_scale: Res<MinimumScale>,
+    max_scale: Res<MaximumScale>,
+    scale_speed: Res<CameraSpeedScale>,
+) {
+    for event in scroll_event.read() {
+        for mut projection in query.iter_mut() {
+            if event.unit != MouseScrollUnit::Line {
+                return;
+            }
+
+            let future_scale = event.y.mul_add(scale_speed.0, projection.scale);
+            if min_scale.0 < future_scale && future_scale < max_scale.0 {
+                projection.scale = future_scale;
+            }
+        }
+    }
+}

crates/border-wars/src/lib.rs

@@ -2,6 +2,7 @@
 
 use bevy::prelude::*;
 
+pub mod camera;
 pub mod map;
 pub mod scenes;
 

crates/border-wars/src/main.rs

@@ -1,11 +1,13 @@
 //! The main entry point of the game.
 
 use bevy::prelude::*;
+use border_wars::camera::CameraPlugin;
 use border_wars::scenes::ScenesPlugin;
 
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
         .add_plugins(ScenesPlugin)
+        .add_plugins(CameraPlugin)
         .run();
 }