Make AppearsOnRadar Conditional & Player Stance Awear

OpenRA.Game/Support/VariableExpression.cs

@@ -20,6 +20,8 @@ namespace OpenRA.Support
 {
 	public abstract class VariableExpression
 	{
+		public static readonly IReadOnlyDictionary<string, int> NoVariables = new ReadOnlyDictionary<string, int>(new Dictionary<string, int>());
+
 		public readonly string Expression;
 		readonly HashSet<string> variables = new HashSet<string>();
 		public IEnumerable<string> Variables { get { return variables; } }

OpenRA.Mods.Common/Traits/Conditions/ConditionalTrait.cs

@@ -18,8 +18,6 @@ namespace OpenRA.Mods.Common.Traits
 	/// <summary>Use as base class for *Info to subclass of ConditionalTrait. (See ConditionalTrait.)</summary>
 	public abstract class ConditionalTraitInfo : IObservesVariablesInfo, IRulesetLoaded
 	{
-		protected static readonly IReadOnlyDictionary<string, int> NoConditions = new ReadOnlyDictionary<string, int>(new Dictionary<string, int>());
-
 		[ConsumedConditionReference]
 		[Desc("Boolean expression defining the condition to enable this trait.")]
 		public readonly BooleanExpression RequiresCondition = null;
@@ -33,7 +31,7 @@ public abstract class ConditionalTraitInfo : IObservesVariablesInfo, IRulesetLoa
 
 		public virtual void RulesetLoaded(Ruleset rules, ActorInfo ai)
 		{
-			EnabledByDefault = RequiresCondition == null || RequiresCondition.Evaluate(NoConditions);
+			EnabledByDefault = RequiresCondition == null || RequiresCondition.Evaluate(VariableExpression.NoVariables);
 		}
 	}
 

OpenRA.Mods.Common/Traits/Conditions/PausableConditionalTrait.cs

@@ -28,7 +28,7 @@ public abstract class PausableConditionalTraitInfo : ConditionalTraitInfo
 		public override void RulesetLoaded(Ruleset rules, ActorInfo ai)
 		{
 			base.RulesetLoaded(rules, ai);
-			PausedByDefault = PauseOnCondition != null && PauseOnCondition.Evaluate(NoConditions);
+			PausedByDefault = PauseOnCondition != null && PauseOnCondition.Evaluate(VariableExpression.NoVariables);
 		}
 	}
 

OpenRA.Mods.Common/Traits/Radar/AppearsOnRadar.cs

@@ -18,38 +18,44 @@
 
 namespace OpenRA.Mods.Common.Traits.Radar
 {
-	public class AppearsOnRadarInfo : ITraitInfo
+	public class AppearsOnRadarInfo : ConditionalTraitInfo
 	{
 		public readonly bool UseLocation = false;
 
-		public object Create(ActorInitializer init) { return new AppearsOnRadar(this); }
+		[Desc("Player stances who can view this actor on radar.")]
+		public readonly Stance ValidStances = Stance.Ally | Stance.Neutral | Stance.Enemy;
+
+		public override object Create(ActorInitializer init) { return new AppearsOnRadar(this); }
 	}
 
-	public class AppearsOnRadar : IRadarSignature, INotifyCreated
+	public class AppearsOnRadar : ConditionalTrait<AppearsOnRadarInfo>, IRadarSignature
 	{
-		readonly AppearsOnRadarInfo info;
+		static readonly IEnumerable<Pair<CPos, Color>> NoCells = Enumerable.Empty<Pair<CPos, Color>>();
 		IRadarColorModifier modifier;
 
 		Color currentColor = Color.Transparent;
 		Func<Pair<CPos, SubCell>, Pair<CPos, Color>> cellToSignature;
 
 		public AppearsOnRadar(AppearsOnRadarInfo info)
-		{
-			this.info = info;
-		}
+			: base(info) { }
 
-		public void Created(Actor self)
+		protected override void Created(Actor self)
 		{
+			base.Created(self);
 			modifier = self.TraitsImplementing<IRadarColorModifier>().FirstOrDefault();
 		}
 
 		public IEnumerable<Pair<CPos, Color>> RadarSignatureCells(Actor self)
 		{
+			var viewer = self.World.RenderPlayer ?? self.World.LocalPlayer;
+			if (IsTraitDisabled || (viewer != null && !Info.ValidStances.HasStance(self.Owner.Stances[viewer])))
+				return NoCells;
+
 			var color = Game.Settings.Game.UsePlayerStanceColors ? self.Owner.PlayerStanceColor(self) : self.Owner.Color.RGB;
 			if (modifier != null)
 				color = modifier.RadarColorOverride(self, color);
 
-			if (info.UseLocation)
+			if (Info.UseLocation)
 				return new[] { Pair.New(self.Location, color) };
 
 			// PERF: Cache cellToSignature delegate to avoid allocations as color does not change often.