feat(taiko): 3 secs preparation before game start

taiko-game/src/app.rs

@@ -51,6 +51,7 @@ pub struct App {
     auto_play: Option<Vec<TaikoNote>>,
     auto_play_combo_sleep: u8,
     guage_color_change: i32,
+    enter_countdown: i16,
 }
 
 impl App {
@@ -105,6 +106,7 @@ impl App {
             auto_play: None,
             auto_play_combo_sleep: 0,
             guage_color_change: 0,
+            enter_countdown: 0,
         })
     }
 
@@ -167,6 +169,8 @@ impl App {
     }
 
     async fn enter_game(&mut self) -> Result<()> {
+        self.enter_countdown = self.args.tps as i16 * -3;
+
         let selected = self.course_selector.selected().unwrap_or(0);
         let mut course = self
             .song
@@ -198,7 +202,7 @@ impl App {
         self.taiko.replace(DefaultTaikoEngine::new(source));
 
         self.player.stop_music().await;
-        self.player.play_music(self.music.as_ref().unwrap()).await;
+        self.player.load_music(self.music.as_ref().unwrap()).await;
 
         Ok(())
     }
@@ -406,7 +410,18 @@ impl App {
                             self.ticks.remove(0);
                         }
 
-                        let player_time = self.player.get_music_time().await;
+                        if self.enter_countdown < 0 {
+                            self.enter_countdown += 1;
+                        } else if self.enter_countdown == 0 {
+                            self.player.play_loaded_music().await;
+                            self.enter_countdown = 1;
+                        }
+
+                        let player_time = if self.enter_countdown <= 0 {
+                            self.enter_countdown as f64 / self.args.tps as f64
+                        } else {
+                            self.player.get_music_time().await
+                        };
                         if self.taiko.is_some() {
                             let taiko = self.taiko.as_mut().unwrap();
 
@@ -480,7 +495,11 @@ impl App {
                         } else {
                             0.0
                         };
-                        let player_time = self.player.get_music_time().await;
+                        let player_time = if self.enter_countdown <= 0 {
+                            self.enter_countdown as f64 / self.args.tps as f64
+                        } else {
+                            self.player.get_music_time().await
+                        };
 
                         let song_name: Option<String> = if self.song.is_none() {
                             None

taiko-game/src/sound.rs

@@ -53,6 +53,12 @@ pub(crate) trait SoundPlayer {
     /// Plays a sound effect.
     async fn play_effect(&mut self, effect: &SoundData);
 
+    /// Loads a background music.
+    async fn load_music(&mut self, music: &SoundData);
+
+    /// Plays a background music after loading it.
+    async fn play_loaded_music(&mut self);
+
     /// Plays a background music.
     async fn play_music(&mut self, music: &SoundData);
 
@@ -118,7 +124,7 @@ impl SoundPlayer for RodioSoundPlayer {
         self.controller.add(source);
     }
 
-    async fn play_music(&mut self, music: &SoundData) {
+    async fn load_music(&mut self, music: &SoundData) {
         let sink = self.sink.lock().await;
 
         let source = rodio::buffer::SamplesBuffer::new(
@@ -131,12 +137,20 @@ impl SoundPlayer for RodioSoundPlayer {
         sink.append(mixer);
         self.controller = controller;
         self.controller.add(source);
-
-        sink.play();
+        sink.pause();
         self.music_start = Some(Instant::now());
         self.music_time = 0.0;
     }
 
+    async fn play_loaded_music(&mut self) {
+        self.resume_music().await
+    }
+
+    async fn play_music(&mut self, music: &SoundData) {
+        self.load_music(music).await;
+        self.play_loaded_music().await;
+    }
+
     async fn play_music_from(&mut self, music: &SoundData, time: f64) {
         let sink = self.sink.lock().await;
         let data = music