Config file for game settings (#17)

* Initial config file implementation

* Log unexpected key and use systems

Uses only ECS systems now to tidy it up. Also will log a warning if
there is an unexpected key in the config file.

* Add clippy lints

Add `semicolon_if_nothing_returned` and `uninlined_format_args` for more
consistent code style

* Update README.md

* Add `shell.nix`

* Add instructions and feature for wayland

* Remove config plugin

We don't need to pretend that we can change the config while the game is
running (yet).

Cargo.toml

@@ -11,9 +11,14 @@ bevy_ninepatch = "0.9"
 iyes_loopless = "0.9"
 leafwing-input-manager = "0.7"
 
+directories = "4.0"
 itertools = "0.10"
 noise = { git = "https://github.com/bsurmanski/noise-rs", rev = "5abdde1b819eccc47e74969c15e1b56ae5a055d6" }
 rand = { version = "0.8", default_features = false, features = ["std", "small_rng"] }
+serde = "1.0"
+serde_derive = "1.0"
+serde_ignored = "0.1.6"
+toml = "0.5"
 
 [dependencies.bevy]
 version = "0.9"

src/audio.rs

@@ -3,15 +3,17 @@ use bevy_kira_audio::prelude::*;
 use iyes_loopless::prelude::*;
 use rand::prelude::*;
 
-use crate::{GameRng, GameState};
+use crate::{config::Config, GameRng, GameState};
 
 pub struct AudioPlugin;
 
 impl Plugin for AudioPlugin {
     fn build(&self, app: &mut App) {
         app.add_event::<PlaySfx>()
             .add_audio_channel::<BgmChannel>()
+            .add_audio_channel::<SfxChannel>()
             .add_startup_system(load_audio)
+            .add_startup_system(set_volume)
             .add_enter_system(GameState::MainMenu, start_title_bgm)
             .add_enter_system(GameState::InGame, start_fight_bgm)
             .add_exit_system(GameState::MainMenu, stop_bgm)
@@ -25,11 +27,14 @@ impl Plugin for AudioPlugin {
     }
 }
 
-/// Resource for the background music channel. Exists so in future a user may change BGM volume
-/// independently of SFX.
+/// Resource for the background music channel.
 #[derive(Resource)]
 struct BgmChannel;
 
+/// Resource for the sound effects channel.
+#[derive(Resource)]
+struct SfxChannel;
+
 /// Event for SFX.
 #[derive(Debug)]
 pub enum PlaySfx {
@@ -38,6 +43,16 @@ pub enum PlaySfx {
     BombFuse,
 }
 
+/// Update the channel volumes based on values in the [`Config`] resource.
+fn set_volume(
+    bgm_channel: Res<AudioChannel<BgmChannel>>,
+    sfx_channel: Res<AudioChannel<SfxChannel>>,
+    config: Res<Config>,
+) {
+    bgm_channel.set_volume(config.bgm_volume);
+    sfx_channel.set_volume(config.sfx_volume);
+}
+
 fn start_title_bgm(audio: Res<AudioChannel<BgmChannel>>, bgm: Res<Bgm>) {
     audio.play(bgm.title_screen.clone()).looped();
 }
@@ -60,7 +75,7 @@ fn stop_bgm(audio: Res<AudioChannel<BgmChannel>>) {
 }
 
 fn play_sfx(
-    audio: Res<Audio>,
+    audio: Res<AudioChannel<SfxChannel>>,
     sfx: Res<Sfx>,
     mut rng: ResMut<GameRng>,
     mut ev_sfx: EventReader<PlaySfx>,

src/config.rs

@@ -0,0 +1,75 @@
+//! Load the settings file for the game. This will be under the config folder by OS convention, for
+//! example:
+//!
+//! Linux: `~/.config/bomby/config.toml`
+//!
+//! Currently, the config is loaded at startup and cannot be changed from inside the game. So, this
+//! module does not export a bevy plugin (yet).
+
+use bevy::prelude::*;
+
+use directories::ProjectDirs;
+use serde_derive::{Deserialize, Serialize};
+
+use std::fs;
+
+const DEFAULT_ASPECT_RATIO: f32 = 16.0 / 9.0;
+const DEFAULT_WINDOW_HEIGHT: f32 = 900.0;
+const DEFAULT_WINDOW_WIDTH: f32 = DEFAULT_WINDOW_HEIGHT * DEFAULT_ASPECT_RATIO;
+
+/// Config resource containing runtime settings for the game.
+#[derive(Resource, Debug, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Config {
+    pub window_resizable: bool,
+    pub window_width: f32,
+    pub window_height: f32,
+    pub bgm_volume: f64,
+    pub sfx_volume: f64,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            window_resizable: true,
+            window_width: DEFAULT_WINDOW_WIDTH,
+            window_height: DEFAULT_WINDOW_HEIGHT,
+            bgm_volume: 1.0,
+            sfx_volume: 1.0,
+        }
+    }
+}
+
+/// Load the [`Config`] or generate a new one and insert it as a resource.
+pub fn load_config() -> Config {
+    let dirs = ProjectDirs::from("com", "Spicy Lobster", "Bomby");
+    let mut config = dirs
+        .map(|dirs| {
+            let mut path = dirs.config_dir().to_path_buf();
+            path.push("config.toml");
+            let config_str = fs::read_to_string(&path).unwrap_or_else(|_| "".to_string());
+            let mut de = toml::de::Deserializer::new(&config_str);
+            let mut unused_keys = Vec::new();
+            let config =
+                serde_ignored::deserialize(&mut de, |path| unused_keys.push(path.to_string()))
+                    .unwrap_or_else(|e| {
+                        warn!("failed to parse config file {path:?}: {e}");
+                        Config::default()
+                    });
+
+            for key in unused_keys {
+                warn!("unrecognised config setting: {key}");
+            }
+            config
+        })
+        .unwrap_or_else(|| {
+            warn!("failed to get config path");
+            Config::default()
+        });
+
+    // Ensure sensible bounds.
+    config.bgm_volume = config.bgm_volume.clamp(0.0, 1.0);
+    config.sfx_volume = config.sfx_volume.clamp(0.0, 1.0);
+
+    config
+}

src/main.rs

@@ -8,16 +8,13 @@ use rand::{rngs::SmallRng, SeedableRng};
 mod audio;
 mod bomb;
 mod camera;
+mod config;
 mod debug;
 mod ldtk;
 mod player;
 mod ui;
 mod z_sort;
 
-const RESOLUTION: f32 = 16.0 / 9.0;
-const WINDOW_HEIGHT: f32 = 900.0;
-const WINDOW_WIDTH: f32 = WINDOW_HEIGHT * RESOLUTION;
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum GameState {
     MainMenu,
@@ -29,22 +26,26 @@ pub enum GameState {
 pub struct GameRng(SmallRng);
 
 fn main() {
+    let config = config::load_config();
+    info!("Initialised config: {config:?}");
+
     App::new()
         .add_loopless_state(GameState::MainMenu)
         .add_plugins(
             DefaultPlugins
                 .set(ImagePlugin::default_nearest())
                 .set(WindowPlugin {
                     window: WindowDescriptor {
-                        width: WINDOW_WIDTH,
-                        height: WINDOW_HEIGHT,
+                        width: config.window_width,
+                        height: config.window_height,
                         title: "Bomby!".to_string(),
-                        resizable: false,
+                        resizable: config.window_resizable,
                         ..default()
                     },
                     ..default()
                 }),
         )
+        .insert_resource(config)
         .add_plugin(bevy_kira_audio::AudioPlugin)
         .add_plugin(audio::AudioPlugin)
         .add_plugin(debug::DebugPlugin)