Testcase

OpenRA.Mods.Common/Scripting/Global/WorldActorConditionGlobal.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Linq;
+using Eluant;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Scripting;
+
+namespace OpenRA.Mods.Common.Scripting
+{
+	[ScriptGlobal("WorldActor")]
+	public class WorldActorConditionGlobal : ScriptGlobal
+	{
+		public WorldActorConditionGlobal(ScriptContext context)
+			: base(context)
+		{
+			externalConditions = context.World.WorldActor.TraitsImplementing<ExternalCondition>().ToArray();
+		}
+
+		readonly ExternalCondition[] externalConditions;
+
+		[Desc("Grant an external condition on world actor and return the revocation token.",
+			"Conditions must be defined on an ExternalConditions trait on the actor.",
+			"If duration > 0 the condition will be automatically revoked after the defined number of ticks.")]
+		public int GrantCondition(string condition, int duration = 0)
+		{
+			var external = Array.Find(externalConditions, t => t.Info.Condition == condition && t.CanGrantCondition(this));
+
+			if (external == null)
+				throw new LuaException($"Condition `{condition}` has not been listed on an enabled ExternalCondition trait");
+
+			return external.GrantCondition(Context.World.WorldActor, this, duration);
+		}
+
+		[Desc("Revoke a condition on world actor using the token returned by GrantCondition.")]
+		public void RevokeCondition(int token)
+		{
+			foreach (var external in externalConditions)
+				if (external.TryRevokeCondition(Context.World.WorldActor, this, token))
+					break;
+		}
+
+		[Desc("Check whether world actor accepts a specific external condition.")]
+		public bool AcceptsCondition(string condition)
+		{
+			return Array.Exists(externalConditions, t => t.Info.Condition == condition && t.CanGrantCondition(this));
+		}
+	}
+}

mods/ra/maps/desert-shellmap/desert-shellmap.lua

@@ -170,6 +170,13 @@ ChronoshiftAlliedUnits = function()
 	Trigger.AfterDelay(DateTime.Seconds(60), ChronoshiftAlliedUnits)
 end
 
+DesertSandStormLoop = function()
+	WorldActor.GrantCondition("sandstorm", 1000)
+	Trigger.AfterDelay(2500, function()
+		DesertSandStormLoop()
+	end)
+end
+
 Ticks = 0
 Speed = 5
 
@@ -188,6 +195,7 @@ WorldLoaded = function()
 	SetupAlliedUnits()
 	SetupFactories()
 	ShipAlliedUnits()
+	DesertSandStormLoop()
 	InsertAlliedChinookReinforcements(Chinook1Entry, HeliPad1)
 	InsertAlliedChinookReinforcements(Chinook2Entry, HeliPad2)
 	PowerProxy = Actor.Create(ProxyType, false, { Owner = Soviets })

mods/ra/maps/desert-shellmap/rules.yaml

@@ -19,6 +19,27 @@ World:
 	LuaScript:
 		Scripts: desert-shellmap.lua
 	-StartGameNotification:
+	ExternalCondition@sandstorm:
+		Condition: sandstorm
+	WeatherOverlay:
+		ChangingWindLevel: false
+		WindLevels: 12, 7, 11, 8, 10, 9
+		WindTick: 150, 550
+		InstantWindChanges: false
+		UseSquares: false
+		ParticleSize: 1, 1
+		ParticleDensityFactor: 32
+		ScatterDirection: 0, 0
+		Gravity: -2.00, 2.00
+		SwingOffset: 0, 0
+		SwingSpeed: 0.001, 0.008
+		SwingAmplitude: 0.2, 0.3
+		ParticleColors: 686064, 986854, B48854, BD8D7E, CAA264, CB9367
+		LineTailAlphaValue: 150
+		InitialParticlePercentage: 0
+		FadeInTicks: 500
+		FadeOutTicks: 750
+		RequiresCondition: sandstorm
 
 ^ExistsInWorld:
 	GivesExperience: