Moved track volume dimming into MusicController.

- Fixes an issue where the first few milliseconds of the theme song would always play at full volume, even if container is not focused.
- Allows easier application to any song.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/states/MainMenu.java

@@ -106,11 +106,6 @@ public class MainMenu extends BasicGameState {
 	 */
 	private float bgAlpha = 0f;
 
-	/**
-	 * Whether the theme song volume has been dimmed.
-	 */
-	private boolean volumeDimmed = false;
-
 	// game-related variables
 	private GameContainer container;
 	private StateBasedGame game;
@@ -259,16 +254,9 @@ public class MainMenu extends BasicGameState {
 			repoButton.hoverUpdate(delta, mouseX, mouseY);
 
 		// window focus change: increase/decrease theme song volume
-		if (MusicController.isThemePlaying()) {
-			boolean hasFocus = container.hasFocus();
-			if (volumeDimmed == hasFocus) {
-				if (hasFocus)  // restored focus
-					MusicController.setVolume(Options.getMusicVolume());
-				else  // lost focus
-					MusicController.setVolume(Options.getMusicVolume() / 3f);
-				volumeDimmed = !hasFocus;
-			}
-		}
+		if (MusicController.isThemePlaying() &&
+		    MusicController.isTrackDimmed() == container.hasFocus())
+				MusicController.toggleTrackDimmed();
 
 		// fade in background
 		if (bgAlpha < 0.9f) {