move HiddenUnderFog, WithMuzzleFlash into modifiers where they belong

OpenRA.Game/Traits/Modifiers/WithMuzzleFlash.cs

@@ -0,0 +1,57 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
+ * This file is part of OpenRA.
+ * 
+ *  OpenRA is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  OpenRA is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU General Public License
+ *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using OpenRA.Graphics;
+
+namespace OpenRA.Traits
+{
+	class WithMuzzleFlashInfo : ITraitInfo, ITraitPrerequisite<RenderSimpleInfo>
+	{
+		public object Create(Actor self) { return new WithMuzzleFlash(self); }
+	}
+
+	class WithMuzzleFlash : INotifyAttack
+	{
+		Animation muzzleFlash;
+		bool isShowing;
+
+		public WithMuzzleFlash(Actor self)
+		{
+			var unit = self.traits.Get<Unit>();
+			var attackInfo = self.Info.Traits.Get<AttackBaseInfo>();
+			var render = self.traits.Get<RenderSimple>();
+
+			muzzleFlash = new Animation(render.GetImage(self), () => unit.Facing);
+			muzzleFlash.Play("muzzle");
+			var len = muzzleFlash.CurrentSequence.Length;
+
+			render.anims.Add("muzzle", new RenderSimple.AnimationWithOffset(
+				muzzleFlash,
+				() => attackInfo.PrimaryOffset.AbsOffset(),
+				() => !isShowing));
+		}
+
+		public void Attacking(Actor self)
+		{
+			isShowing = true;
+			muzzleFlash.PlayThen("muzzle", () => isShowing = false);
+		}
+	}
+}