MRJ works; moved ProvidesRadar.IsActive update to Tick to avoid desync if any other actor code relies on it.

OpenRa.Game/Chrome.cs

@@ -307,7 +307,7 @@ namespace OpenRa
 		{
 			var hasNewRadar = world.Actors.Any(a => a.Owner == world.LocalPlayer 
 				&& a.traits.Contains<ProvidesRadar>() 
-				&& a.traits.Get<ProvidesRadar>().IsActive(a));
+				&& a.traits.Get<ProvidesRadar>().IsActive);
 			
 			if (hasNewRadar != hasRadar)
 			{

OpenRa.Game/OpenRa.Game.csproj

@@ -229,6 +229,7 @@
     <Compile Include="Traits\ConstructionYard.cs" />
     <Compile Include="Traits\IronCurtain.cs" />
     <Compile Include="Traits\IronCurtainable.cs" />
+    <Compile Include="Traits\JamsRadar.cs" />
     <Compile Include="Traits\LightPaletteRotator.cs" />
     <Compile Include="Traits\LimitedAmmo.cs" />
     <Compile Include="Traits\Passenger.cs" />

OpenRa.Game/Traits/Building.cs

@@ -40,7 +40,14 @@ namespace OpenRa.Traits
 		[Sync]
 		bool manuallyDisabled = false;
 		public bool ManuallyDisabled { get { return manuallyDisabled; } }
-		public bool Disabled { get { return (manuallyDisabled || (Info.RequiresPower && self.Owner.GetPowerState() != PowerState.Normal)); } }
+		public bool Disabled
+		{
+			get
+			{
+				return (manuallyDisabled || 
+					(Info.RequiresPower && self.Owner.GetPowerState() != PowerState.Normal));
+			}
+		}
 		bool wasDisabled = false;
 		
 		public Building(Actor self)

OpenRa.Game/Traits/JamsRadar.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Traits
+{
+	class JamsRadarInfo : StatelessTraitInfo<JamsRadar>
+	{
+		public readonly int Range = 0;
+	}
+
+	class JamsRadar {}
+}

OpenRa.Game/Traits/ProvidesRadar.cs

@@ -1,20 +1,26 @@
-
+using System.Linq;
+
 namespace OpenRa.Traits
 {
 	class ProvidesRadarInfo : StatelessTraitInfo<ProvidesRadar> {}
 
-	class ProvidesRadar
+	class ProvidesRadar : ITick
 	{
-		public bool IsActive(Actor self)
+		public bool IsActive { get; private set; }
+
+		public void Tick(Actor self) { IsActive = UpdateActive(self); }
+
+		bool UpdateActive(Actor self)
 		{
-			// TODO: Check for nearby MRJ
-			
 			// Check if powered
 			var b = self.traits.Get<Building>();
-			if (b != null && b.Disabled)
-				return false;
-			
-			return true;
+			if (b != null && b.Disabled) return false;
+
+			var isJammed = self.World.Actors.Any(a => a.traits.Contains<JamsRadar>()
+				&& self.Owner != a.Owner
+				&& (self.Location - a.Location).Length < a.Info.Traits.Get<JamsRadarInfo>().Range);
+
+			return !isJammed;
 		}
 	}
 }