added fade possibility to backgroundmusic.cs

Assets/Scripts/Audio/BackgroundMusic.cs

@@ -14,6 +14,7 @@ public class BackgroundMusic : MonoBehaviour {
 	private bool inTransition = false;
 	private int preTransitionSample = 0;
 	private double lastUpdate = 0;
+	private float fadePerSecond = -1f;
 
 	// Use this for initialization
 	void Start () {
@@ -34,10 +35,18 @@ public class BackgroundMusic : MonoBehaviour {
 		if (AS[current].timeSamples != preTransitionSample)
 		{
 			inTransition = false;
+			AS[other].volume = 1;
+			fadePerSecond = -1;
 			Debug.Log("Music transition complete, playing " + AS[current].clip.name +
 			"\nSample new: " + AS[current].timeSamples + ", Sample old: " + AS[1-current].timeSamples +
 			"\nCurrent global time: " + AudioSettings.dspTime + ", Last update at " + lastUpdate);
 		}
+		if (fadePerSecond >= 0 && AS[1 - current].isPlaying)
+		{
+			AS[1 - current].volume -= fadePerSecond * Time.deltaTime;
+		}
+		
+		
 		/*else
 		{
 			lastUpdate = AudioSettings.dspTime;
@@ -72,7 +81,7 @@ public class BackgroundMusic : MonoBehaviour {
 		"\nCurrent Global Time: " + AudioSettings.dspTime);
 	}
 
-	public void TransitionTo(MusicObject target)
+	public void TransitionTo(MusicObject target, float fadeDuration = -1)
 	{
 		if (inTransition)
 		{
@@ -86,6 +95,12 @@ public class BackgroundMusic : MonoBehaviour {
 		}
 
 		inTransition = true;
+		
+		if (fadeDuration >= 0)
+		{
+			fadePerSecond = 1 / fadeDuration;
+			Play(target, AS[current].clip.samples + (int)(AS[current].clip.frequency * fadeDuration), 0);
+		}
 
 		int iTarget;
 		for (iTarget = 0; iTarget < currentMusic.targets.Length; iTarget++) //search for TransitionTarget that matches target