some basic plane behavior on Yak

OpenRa.Game/OpenRa.Game.csproj

@@ -106,6 +106,7 @@
     <Compile Include="Support\PerfHistory.cs" />
     <Compile Include="Traits\AcceptsOre.cs" />
     <Compile Include="Traits\Activities\Attack.cs" />
+    <Compile Include="Traits\Activities\Fly.cs" />
     <Compile Include="Traits\Activities\IActivity.cs" />
     <Compile Include="Traits\Activities\DeliverOre.cs" />
     <Compile Include="Traits\Activities\DeployMcv.cs" />
@@ -169,6 +170,7 @@
     <Compile Include="Traits\Fake.cs" />
     <Compile Include="Traits\Harvester.cs" />
     <Compile Include="Traits\Helicopter.cs" />
+    <Compile Include="Traits\Plane.cs" />
     <Compile Include="Traits\ProductionQueue.cs" />
     <Compile Include="Traits\RenderBuildingCharge.cs" />
     <Compile Include="Traits\RenderInfantry.cs" />
@@ -184,6 +186,7 @@
     <Compile Include="Traits\Cloak.cs" />
     <Compile Include="Traits\RenderUnit.cs" />
     <Compile Include="Traits\RenderUnitMuzzleFlash.cs" />
+    <Compile Include="Traits\RenderUnitPlane.cs" />
     <Compile Include="Traits\RenderUnitReload.cs" />
     <Compile Include="Traits\RenderUnitRotor.cs" />
     <Compile Include="Traits\RenderUnitSpinner.cs" />

OpenRa.Game/Traits/Activities/Fly.cs

@@ -0,0 +1,97 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits.Activities
+{
+	class Fly : IActivity
+	{
+		readonly int2 Cell;
+		bool isCanceled;
+
+		public Fly(int2 cell) { Cell = cell; }
+
+		public IActivity NextActivity { get; set; }
+
+		const int CruiseAltitude = 20;
+		
+		public IActivity Tick(Actor self)
+		{
+			if (isCanceled) return NextActivity;
+
+			var d = Util.CenterOfCell(Cell) - self.CenterLocation;
+			if (d.LengthSquared < 50)		/* close enough */
+				return NextActivity;
+
+			var unit = self.traits.Get<Unit>();
+
+			if (unit.Altitude < CruiseAltitude)
+				++unit.Altitude;
+
+			var desiredFacing = Util.GetFacing(d, unit.Facing);
+			if (unit.Altitude == CruiseAltitude)
+				Util.TickFacing(ref unit.Facing, desiredFacing, self.Info.ROT);
+			var speed = .2f * Util.GetEffectiveSpeed(self);
+			var angle = unit.Facing / 128f * Math.PI;
+
+			self.CenterLocation += speed * -float2.FromAngle((float)angle);
+			self.Location = ((1 / 24f) * self.CenterLocation).ToInt2();
+
+			return null;
+		}
+
+		public void Cancel(Actor self) { isCanceled = true; NextActivity = null; }
+	}
+
+	class FlyTimed : IActivity
+	{
+		public IActivity NextActivity { get; set; }
+		int remainingTicks;
+
+		public FlyTimed(int ticks) { remainingTicks = ticks; }
+		
+		public IActivity Tick(Actor self)
+		{
+			if (remainingTicks == 0)
+				return NextActivity;
+
+			--remainingTicks;
+
+			var unit = self.traits.Get<Unit>();
+			var speed = .2f * Util.GetEffectiveSpeed(self);
+			var angle = unit.Facing / 128f * Math.PI;
+
+			self.CenterLocation += speed * -float2.FromAngle((float)angle);
+			self.Location = ((1 / 24f) * self.CenterLocation).ToInt2();
+
+			return null;
+		}
+
+		public void Cancel(Actor self) { remainingTicks = 0; NextActivity = null; }
+	}
+
+	class Circle : IActivity
+	{
+		public IActivity NextActivity { get; set; }
+		bool isCanceled;
+		readonly int2 Cell;
+
+		public Circle(int2 cell) { Cell = cell; }
+		
+		public IActivity Tick(Actor self)
+		{
+			if (isCanceled) return NextActivity;
+			return new Fly(Cell)
+			{
+				NextActivity =
+					new FlyTimed(50)
+					{
+						NextActivity = this
+					}
+			};
+		}
+
+		public void Cancel(Actor self) { isCanceled = true; NextActivity = null; }
+	}
+}

OpenRa.Game/Traits/Plane.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Traits.Activities;
+
+namespace OpenRa.Game.Traits
+{
+	class Plane : IOrder
+	{
+		public Plane(Actor self)
+		{
+		}
+
+		public Order IssueOrder(Actor self, int2 xy, MouseInput mi, Actor underCursor)
+		{
+			if (mi.Button == MouseButton.Left) return null;
+			if (underCursor == null)
+				return Order.Move(self, xy);
+			return null;
+		}
+
+		public void ResolveOrder(Actor self, Order order)
+		{
+			if (order.OrderString == "Move")
+			{
+				self.CancelActivity();
+				self.QueueActivity(new Circle(order.TargetLocation));
+			}
+		}
+	}
+}

OpenRa.Game/Traits/RenderUnitPlane.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Graphics;
+
+namespace OpenRa.Game.Traits
+{
+	class RenderUnitPlane : RenderUnit
+	{
+		public RenderUnitPlane(Actor self)
+			: base(self) {}
+
+		public override IEnumerable<Tuple<Sprite, float2, int>> Render(Actor self)
+		{
+			var unit = self.traits.Get<Unit>();
+
+			yield return Util.CenteredShadow(self, anim.Image, self.CenterLocation);
+			var p = self.CenterLocation - new float2(0, unit.Altitude);
+			yield return Util.Centered(self, anim.Image, p);
+		}
+	}
+}

units.ini

@@ -161,7 +161,7 @@ LongDesc=Fast Ground-Attack Plane.\n  Strong vs Buildings\n  Weak vs Infantry, L
 [YAK]
 Description=Yak Attack Plane
 BuiltAt=afld
-Traits=Unit, Mobile, RenderUnit
+Traits=Unit, Plane, RenderUnitPlane
 InitialFacing=192
 LongDesc=Anti-Tanks & Anti-Infantry Plane.\n  Strong vs Infantry, Tanks\n  Weak vs Buildings
 [TRAN]