add Effect.ChangeLighting(red, green, blue, ambient) to Lua API

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

@@ -9,6 +9,7 @@
 #endregion
 
 using System.Collections.Generic;
+using Eluant;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Scripting;
 
@@ -18,11 +19,13 @@ namespace OpenRA.Mods.Common.Scripting
 	public class EffectGlobal : ScriptGlobal
 	{
 		readonly IEnumerable<FlashPaletteEffect> fpes;
+		readonly GlobalLightingPaletteEffect lighting;
 
 		public EffectGlobal(ScriptContext context)
 			: base(context)
 		{
 			fpes = context.World.WorldActor.TraitsImplementing<FlashPaletteEffect>();
+			lighting = context.World.WorldActor.TraitOrDefault<GlobalLightingPaletteEffect>();
 		}
 
 		[Desc("Controls the `FlashPaletteEffect` trait.")]
@@ -32,5 +35,17 @@ namespace OpenRA.Mods.Common.Scripting
 				if (fpe.Info.Type == type)
 					fpe.Enable(ticks);
 		}
+
+		[Desc("Dynamically adjusts the `GlobalLightingPaletteEffect` trait.")]
+		public void ChangeLighting(double red, double green, double blue, double ambient)
+		{
+			if (lighting == null)
+				throw new LuaException("GlobalLightingPaletteEffect needs to be added to the World actor first.");
+
+			lighting.Red = (float)red;
+			lighting.Green = (float)green;
+			lighting.Blue = (float)blue;
+			lighting.Ambient = (float)ambient;
+		}
 	}
 }