power tracks damaged/destroyed correctly

OpenRa.Game/Player.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRa.Game.GameRules;
+using OpenRa.Game.Traits;
 
 namespace OpenRa.Game
 {
@@ -35,14 +36,27 @@ namespace OpenRa.Game
 				ProductionInit( cat );
 		}
 
-		public void ChangePower(int dPower)
+		void UpdatePower()
 		{
-			if (dPower > 0)
-				powerProvided += dPower;
-			if (dPower < 0)
-				powerDrained -= dPower;
+			var oldBalance = powerProvided - powerDrained;
 
-			if (powerDrained > powerProvided)
+			powerProvided = 0;
+			powerDrained = 0;
+
+			var myBuildings = Game.world.Actors
+				.Where(a => a.Owner == this && a.traits.Contains<Building>());
+
+			foreach (var a in myBuildings)
+			{
+				var bi = a.Info as BuildingInfo;
+				if (bi.Power > 0)		/* todo: is this how real-ra scales it? */
+					powerProvided += (a.Health * bi.Power) / bi.Strength;
+				else 
+					powerDrained -= bi.Power;
+			}
+
+			if (powerProvided - powerDrained < 0)
+				if (powerProvided - powerDrained  != oldBalance)
 					GiveAdvice("lopower1.aud");
 		}
 
@@ -99,6 +113,8 @@ namespace OpenRa.Game
 
 		public void Tick()
 		{
+			UpdatePower();
+
 			foreach( var p in production )
 				if( p.Value != null )
 					p.Value.Tick( this );

OpenRa.Game/Traits/Building.cs

@@ -2,7 +2,7 @@
 
 namespace OpenRa.Game.Traits
 {
-	class Building : ITick, INotifyBuildComplete
+	class Building : ITick
 	{
 		public readonly BuildingInfo unitInfo;
 
@@ -19,11 +19,5 @@ namespace OpenRa.Game.Traits
 
 			first = false;
 		}
-
-		public void BuildingComplete(Actor self)
-		{
-			if (self.Owner != null)
-				self.Owner.ChangePower(unitInfo.Power);
-		}
 	}
 }