Refactor McvDeploy into a generic 'transform into another actor' trait

OpenRa.Game/Traits/Activities/TransformIntoActor.cs

@@ -0,0 +1,47 @@
+using System;
+
+namespace OpenRa.Traits.Activities
+{
+	class TransformIntoActor : IActivity
+	{
+		string actor = null;
+		int2 offset;
+		string[] sounds = null;
+		bool transferPercentage;
+		
+		bool isCanceled;
+		
+		public TransformIntoActor(string actor, int2 offset, bool transferHealthPercentage, string[] sounds)
+		{
+			this.actor = actor;
+			this.offset = offset;
+			this.sounds = sounds;
+			this.transferPercentage = transferHealthPercentage;
+		}
+		
+		public IActivity NextActivity { get; set; }
+
+		public IActivity Tick( Actor self )
+		{
+			if (isCanceled) return NextActivity;
+			
+			self.World.AddFrameEndTask( _ =>
+			{
+				var oldHP = self.GetMaxHP();
+				var newHP = Rules.Info[actor].Traits.Get<OwnedActorInfo>().HP;
+				var newHealth = (transferPercentage) ? (int)((float)self.Health/oldHP*newHP) : Math.Min(self.Health, newHP);
+				
+				self.Health = 0;
+				self.World.Remove( self );
+				foreach (var s in sounds)
+					Sound.PlayToPlayer(self.Owner, s);
+
+				var a = self.World.CreateActor( actor, self.Location + offset, self.Owner );
+				a.Health = newHealth;
+			} );
+			return this;
+		}
+		
+		public void Cancel(Actor self) { isCanceled = true; NextActivity = null; }
+	}
+}