Fix processed RON assets being ignored (#48)

## Summary
- share custom RON asset loaders between the game and asset processor
- register image, font, and glTF loaders in the headless processor
- prevent `game_settings.ron` and `game.stylesheet.ron` from receiving ignored processed metadata

Reviewed-on: #48
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/lib.rs

@@ -32,7 +32,13 @@ use clap::Parser;
 use ron_asset_manager::RonAssetPlugin;
 
 use crate::{
-    camera::MatchCameraPlugin, fighter::manifest::FighterManifest, game_settings::GameSettings, schedule::GameplaySchedulePlugin, stage::manifest::StageManifest, ui::InGameUIPlugin,
+    camera::MatchCameraPlugin,
+    fighter::manifest::FighterManifest,
+    game_settings::GameSettings,
+    menus::style::FGUiStyle,
+    schedule::GameplaySchedulePlugin,
+    stage::manifest::StageManifest,
+    ui::InGameUIPlugin,
 };
 
 mod args;
@@ -80,6 +86,20 @@ pub enum AppState {
 #[derive(Default)]
 pub struct GamePlugin;
 
+/// Registers every custom asset loader used by the game and asset processor.
+pub struct GameAssetPlugin;
+
+impl Plugin for GameAssetPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_plugins((
+            RonAssetPlugin::<FighterManifest>::create("fighter.ron"),
+            RonAssetPlugin::<StageManifest>::create("stage.ron"),
+            RonAssetPlugin::<GameSettings>::create("ron"),
+            RonAssetPlugin::<FGUiStyle>::create("stylesheet.ron"),
+        ));
+    }
+}
+
 impl Plugin for GamePlugin {
     fn build(&self, app: &mut App) {
         // Each module owns its own systems, rollback registrations and
@@ -99,9 +119,7 @@ impl Plugin for GamePlugin {
                 scripting::importer::FighterScriptImportPlugin,
                 stage::StagePlugin,
                 MatchCameraPlugin,
-                RonAssetPlugin::<FighterManifest>::create("fighter.ron"),
-                RonAssetPlugin::<StageManifest>::create("stage.ron"),
-                RonAssetPlugin::<GameSettings>::create("ron"),
+                GameAssetPlugin,
                 InGameUIPlugin,
             ))
             .add_plugins(menus::MenuPlugin)
@@ -155,13 +173,14 @@ impl Plugin for GamePlugin {
     }
 }
 
-/// Registers only the custom asset processors used by CI and release builds.
-/// The processing binary adds this plugin without starting the game.
+/// Registers the custom asset loaders and processors used by CI and release
+/// builds. The processing binary adds this plugin without starting the game.
 pub struct AssetProcessingPlugin;
 
 impl Plugin for AssetProcessingPlugin {
     fn build(&self, app: &mut App) {
         app.add_plugins((
+            GameAssetPlugin,
             scripting::importer::FighterScriptImportPlugin,
             fighter::baked_animation::BakedAnimationAssetProcessingPlugin,
         ));