cargo: added cargo-related sequences for APC/LST/TRAN; moved Passengers onto UnitInfo for convenience (and to allow garrisoning without a big hack); added Cargo trait to all known transports

OpenRa.Game/Traits/Activities/UnloadCargo.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits.Activities
+{
+	class UnloadCargo : IActivity
+	{
+		public IActivity NextActivity { get; set; }
+		bool isCanceled;
+
+		public IActivity Tick(Actor self)
+		{
+			if (isCanceled) return NextActivity;
+
+			// if we're a thing that can turn, turn to the
+			// right facing for the unload animation
+			var unit = self.traits.GetOrDefault<Unit>();
+			if (unit != null && unit.Facing != self.Info.UnloadFacing)
+				return Util.SequenceActivities(new Turn(self.Info.UnloadFacing), this);
+
+			// todo: play the `open` anim (or the `close` anim backwards)
+			// todo: unload all the cargo
+			// todo: play the `close` anim (or the `open` anim backwards)
+
+			// as for open/close... the westwood guys suck at being consistent.
+
+			return this;
+		}
+
+		public void Cancel(Actor self) { NextActivity = null; isCanceled = true; }
+	}
+}