Introducing per-player shrouds.

- Each player has their own shroud and their visibility does not extend outside of the shroud. 
- Units and buildings can no longer target other units outside of their visibility. Buildings can still be targetted if they have been explored.
- GPS will provide visibility in the fog-of-war.
- Spies that infiltrate radar domes will gain their victim's exploration and reset it on all clients (if the victim does not have GPS)

OpenRA.Mods.RA/SupportPowers/ChronoshiftPower.cs

@@ -45,9 +45,8 @@ namespace OpenRA.Mods.RA
 				var targetCell = target.Location + (order.TargetLocation - order.ExtraLocation);
 				var cpi = Info as ChronoshiftPowerInfo;
 
-				if (cs.CanChronoshiftTo(target, targetCell, true))
-					cs.Teleport(target, targetCell,
-						cpi.Duration * 25, cpi.KillCargo, self);
+				if (self.Owner.Shroud.IsExplored(targetCell) && cs.CanChronoshiftTo(target, targetCell))
+					cs.Teleport(target, targetCell, cpi.Duration * 25, cpi.KillCargo, self);
 			}
 		}
 
@@ -61,6 +60,48 @@ namespace OpenRA.Mods.RA
 
 			return units.Distinct().Where(a => a.HasTrait<Chronoshiftable>());
 		}
+		
+		
+		public bool SimilarTerrain(CPos xy, CPos sourceLocation) {
+			
+			if (!self.Owner.Shroud.IsExplored(xy))
+				return false;
+			
+			int range = (Info as ChronoshiftPowerInfo).Range;
+			var sourceTiles = self.World.FindTilesInCircle(xy, range);
+			var destTiles = self.World.FindTilesInCircle(sourceLocation, range);
+			List<string> sourceTerrain = new List<string>();
+			List<string> destTerrain = new List<string>();
+			
+			int j = 0;
+			foreach (var t in sourceTiles) {
+				j = j + 1;
+				if (!self.Owner.Shroud.IsExplored(t))
+					return false;
+				sourceTerrain.Add(self.World.GetTerrainType( t ));
+			}
+			j = 0;
+			foreach (var t in destTiles) {
+				j = j + 1;
+				if (!self.Owner.Shroud.IsExplored(t)) {
+					return false;
+				}
+				self.World.GetTerrainType( t );
+				destTerrain.Add(self.World.GetTerrainType( t ));
+			}
+			
+			// HACK but I don't want to write a comparison function
+			if (sourceTerrain.Count != destTerrain.Count)
+				return false;
+			
+			for (int i = 0; i < sourceTerrain.Count; i++) {
+			        if (!sourceTerrain[i].Equals(destTerrain[i]))
+			            return false;
+			}
+			
+			return true;
+		}
+		
 
 		class SelectTarget : IOrderGenerator
 		{
@@ -99,8 +140,11 @@ namespace OpenRA.Mods.RA
 			{
 				var xy = Game.viewport.ViewToWorld(Viewport.LastMousePos);
 				var targetUnits = power.UnitsInRange(xy);
-				foreach (var unit in targetUnits)
-					wr.DrawSelectionBox(unit, Color.Red);
+				foreach (var unit in targetUnits) {
+					if (manager.self.Owner.Shroud.IsTargetable(unit) || manager.self.Owner.HasFogVisibility()) {
+						wr.DrawSelectionBox(unit, Color.Red);
+					}
+				}
 			}
 
 			public void RenderBeforeWorld(WorldRenderer wr, World world)
@@ -175,8 +219,11 @@ namespace OpenRA.Mods.RA
 
 			public void RenderAfterWorld(WorldRenderer wr, World world)
 			{
-				foreach (var unit in power.UnitsInRange(sourceLocation))
-					wr.DrawSelectionBox(unit, Color.Red);
+				foreach (var unit in power.UnitsInRange(sourceLocation)) {
+					if (manager.self.Owner.Shroud.IsTargetable(unit) || manager.self.Owner.HasFogVisibility()) {
+						wr.DrawSelectionBox(unit, Color.Red);
+					}
+				}
 			}
 
 			public void RenderBeforeWorld(WorldRenderer wr, World world)
@@ -194,20 +241,24 @@ namespace OpenRA.Mods.RA
 				// Unit previews
 				foreach (var unit in power.UnitsInRange(sourceLocation))
 				{
-					var targetCell = unit.Location + (xy - sourceLocation);
-					foreach (var r in unit.Render())
-						r.Sprite.DrawAt(r.Pos - Traits.Util.CenterOfCell(unit.Location).ToFloat2() + Traits.Util.CenterOfCell(targetCell).ToFloat2(),
-							wr.GetPaletteIndex(r.Palette),
-							r.Scale*r.Sprite.size);
+					if (manager.self.Owner.Shroud.IsTargetable(unit)) {
+						var targetCell = unit.Location + (xy - sourceLocation);
+						foreach (var r in unit.Render())
+                            r.Sprite.DrawAt(r.Pos - Traits.Util.CenterOfCell(unit.Location).ToFloat2() + Traits.Util.CenterOfCell(targetCell).ToFloat2(),
+								wr.GetPaletteIndex(r.Palette),
+								r.Scale*r.Sprite.size);
+					}
 				}
 
 				// Unit tiles
 				foreach (var unit in power.UnitsInRange(sourceLocation))
 				{
-					var targetCell = unit.Location + (xy - sourceLocation);
-					var canEnter = unit.Trait<Chronoshiftable>().CanChronoshiftTo(unit,targetCell, false);
-					var tile = canEnter ? validTile : invalidTile;
-					tile.DrawAt( wr, targetCell.ToPPos().ToFloat2(), "terrain" );
+					if (manager.self.Owner.Shroud.IsTargetable(unit)) {
+						var targetCell = unit.Location + (xy - sourceLocation);
+						var canEnter = ((manager.self.Owner.Shroud.IsExplored(targetCell) || manager.self.Owner.HasFogVisibility())&& unit.Trait<Chronoshiftable>().CanChronoshiftTo(unit,targetCell));
+						var tile = canEnter ? validTile : invalidTile;
+						tile.DrawAt( wr, targetCell.ToPPos().ToFloat2(), "terrain" );
+					}
 				}
 			}
 
@@ -217,12 +268,18 @@ namespace OpenRA.Mods.RA
 				foreach (var unit in power.UnitsInRange(sourceLocation))
 				{
 					var targetCell = unit.Location + (xy - sourceLocation);
-					if (unit.Trait<Chronoshiftable>().CanChronoshiftTo(unit,targetCell, false))
+					if (manager.self.Owner.Shroud.IsExplored(targetCell) && unit.Trait<Chronoshiftable>().CanChronoshiftTo(unit,targetCell))
 					{
 						canTeleport = true;
 						break;
 					}
 				}
+				if (!canTeleport) {
+					// Check the terrain types. This will allow chronoshifts to occur on empty terrain to terrain of
+					// a similar type. This also keeps the cursor from changing in non-visible property, alerting the
+					// chronoshifter of enemy unit presence
+					canTeleport = power.SimilarTerrain(sourceLocation,xy);
+				}
 				return canTeleport;
 			}