Overhaul Land activity:

- Landing on an actor is no longer blocked by the underlying terrain - Land in a nearby cell if the requested location is blocked - Internally manages the fixed-wing landing sequence - ProductionAirdrop transport waits until the exit is free before landing
2019-06-30 11:56:26 +00:00
parent ff9db0bf7a
commit adecd4ca87
7 changed files with 257 additions and 186 deletions
--- a/OpenRA.Mods.Common/Activities/Air/Land.cs
+++ b/OpenRA.Mods.Common/Activities/Air/Land.cs
@@ -9,6 +9,8 @@
 */
 #endregion

+using System;
+using System.Collections.Generic;
 using OpenRA.Activities;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Traits;
@@ -17,25 +19,57 @@ namespace OpenRA.Mods.Common.Activities
 {
 	public class Land : Activity
 	{
-		readonly Target target;
 		readonly Aircraft aircraft;
 		readonly WVec offset;
+		readonly int desiredFacing;
+		readonly bool assignTargetOnFirstRun;
+		readonly CPos[] clearCells;
+		readonly WDist landRange;

+		Target target;
+		WPos targetPosition;
+		CPos landingCell;
 		bool landingInitiated;
-		bool soundPlayed;
+		bool finishedApproach;

-		public Land(Actor self, Target t, WVec offset)
+		public Land(Actor self, int facing = -1)
+			: this(self, Target.Invalid, new WDist(-1), WVec.Zero, facing, null)
 		{
-			target = t;
-			aircraft = self.Trait<Aircraft>();
-			this.offset = offset;
+			assignTargetOnFirstRun = true;
 		}

-		public Land(Actor self, Target t)
-			: this(self, t, WVec.Zero) { }
+		public Land(Actor self, Target target, int facing = -1)
+			: this(self, target, new WDist(-1), WVec.Zero, facing) { }

-		public Land(Actor self)
-			: this(self, Target.FromPos(Aircraft.GroundPosition(self)), WVec.Zero) { }
+		public Land(Actor self, Target target, WDist landRange, int facing = -1)
+			: this(self, target, landRange, WVec.Zero, facing) { }
+
+		public Land(Actor self, Target target, WVec offset, int facing = -1)
+			: this(self, target, WDist.Zero, offset, facing) { }
+
+		public Land(Actor self, Target target, WDist landRange, WVec offset, int facing = -1, CPos[] clearCells = null)
+		{
+			aircraft = self.Trait<Aircraft>();
+			this.target = target;
+			this.offset = offset;
+			this.clearCells = clearCells ?? new CPos[0];
+			this.landRange = landRange.Length >= 0 ? landRange : aircraft.Info.LandRange;
+
+			// NOTE: desiredFacing = -1 means we should not prefer any particular facing and instead just
+			// use whatever facing gives us the most direct path to the landing site.
+			if (facing == -1 && aircraft.Info.TurnToLand)
+				desiredFacing = aircraft.Info.InitialFacing;
+			else
+				desiredFacing = facing;
+		}
+
+		protected override void OnFirstRun(Actor self)
+		{
+			// When no target is provided we should land in the most direct manner possible.
+			// TODO: For fixed-wing aircraft self.Location is not necessarily the most direct landing site.
+			if (assignTargetOnFirstRun)
+				target = Target.FromCell(self.World, self.Location);
+		}

 		public override Activity Tick(Actor self)
 		{
@@ -48,73 +82,177 @@ namespace OpenRA.Mods.Common.Activities

 			if (IsCanceling || target.Type == TargetType.Invalid)
 			{
-				// We must return the actor to a sensible height before continuing.
-				// If the aircraft lands when idle and is idle, continue landing,
-				// otherwise climb back to CruiseAltitude.
-				// TODO: Remove this after fixing all activities to work properly with arbitrary starting altitudes.
-				var continueLanding = aircraft.Info.LandWhenIdle && self.CurrentActivity.IsCanceling && self.CurrentActivity.NextActivity == null;
-				if (!continueLanding)
+				if (landingInitiated)
 				{
-					var dat = self.World.Map.DistanceAboveTerrain(aircraft.CenterPosition);
-					if (dat > aircraft.LandAltitude && dat < aircraft.Info.CruiseAltitude)
+					// We must return the actor to a sensible height before continuing.
+					// If the aircraft lands when idle and is idle, continue landing,
+					// otherwise climb back to CruiseAltitude.
+					// TODO: Remove this after fixing all activities to work properly with arbitrary starting altitudes.
+					var continueLanding = aircraft.Info.LandWhenIdle && self.CurrentActivity.IsCanceling && self.CurrentActivity.NextActivity == null;
+					if (!continueLanding)
 					{
-						QueueChild(self, new TakeOff(self), true);
-						return this;
-					}
+						var dat = self.World.Map.DistanceAboveTerrain(aircraft.CenterPosition);
+						if (dat > aircraft.LandAltitude && dat < aircraft.Info.CruiseAltitude)
+						{
+							QueueChild(self, new TakeOff(self), true);
+							return this;
+						}

-					aircraft.RemoveInfluence();
-					return NextActivity;
+						aircraft.RemoveInfluence();
+						return NextActivity;
+					}
 				}
+				else
+					return NextActivity;
+			}
+
+			var pos = aircraft.CenterPosition;
+
+			// Reevaluate target position in case the target has moved.
+			targetPosition = target.CenterPosition + offset;
+			landingCell = self.World.Map.CellContaining(targetPosition);
+
+			// We are already at the landing location.
+			if ((targetPosition - pos).LengthSquared == 0)
+				return NextActivity;
+
+			// Look for free landing cell
+			if (target.Type == TargetType.Terrain && !landingInitiated)
+			{
+				var targetLocation = aircraft.FindLandingLocation(landingCell, landRange);
+				if (!targetLocation.HasValue)
+				{
+					// Maintain holding pattern.
+					if (aircraft.Info.CanHover)
+						QueueChild(self, new Wait(25), true);
+					else
+						QueueChild(self, new FlyCircle(self, 25), true);
+					return this;
+				}
+
+				target = Target.FromCell(self.World, targetLocation.Value);
+				targetPosition = target.CenterPosition + offset;
+				landingCell = self.World.Map.CellContaining(targetPosition);
+			}
+
+			// Move towards landing location
+			if (aircraft.Info.VTOL && (pos - targetPosition).HorizontalLengthSquared != 0)
+			{
+				QueueChild(self, new Fly(self, Target.FromPos(targetPosition)), true);
+
+				if (desiredFacing != -1)
+					QueueChild(self, new Turn(self, desiredFacing));
+
+				return this;
+			}
+
+			if (!aircraft.Info.VTOL && !finishedApproach)
+			{
+				// Calculate approach trajectory
+				var altitude = aircraft.Info.CruiseAltitude.Length;
+
+				// Distance required for descent.
+				var landDistance = altitude * 1024 / aircraft.Info.MaximumPitch.Tan();
+
+				// Approach landing from the opposite direction of the desired facing
+				// TODO: Calculate sensible trajectory without preferred facing.
+				var rotation = WRot.Zero;
+				if (desiredFacing != -1)
+					rotation = WRot.FromFacing(desiredFacing);
+
+				var approachStart = targetPosition + new WVec(0, landDistance, altitude).Rotate(rotation);
+
+				// Add 10% to the turning radius to ensure we have enough room
+				var speed = aircraft.MovementSpeed * 32 / 35;
+				var turnRadius = Fly.CalculateTurnRadius(speed, aircraft.Info.TurnSpeed);
+
+				// Find the center of the turning circles for clockwise and counterclockwise turns
+				var angle = WAngle.FromFacing(aircraft.Facing);
+				var fwd = -new WVec(angle.Sin(), angle.Cos(), 0);
+
+				// Work out whether we should turn clockwise or counter-clockwise for approach
+				var side = new WVec(-fwd.Y, fwd.X, fwd.Z);
+				var approachDelta = self.CenterPosition - approachStart;
+				var sideTowardBase = new[] { side, -side }
+					.MinBy(a => WVec.Dot(a, approachDelta));
+
+				// Calculate the tangent line that joins the turning circles at the current and approach positions
+				var cp = self.CenterPosition + turnRadius * sideTowardBase / 1024;
+				var posCenter = new WPos(cp.X, cp.Y, altitude);
+				var approachCenter = approachStart + new WVec(0, turnRadius * Math.Sign(self.CenterPosition.Y - approachStart.Y), 0);
+				var tangentDirection = approachCenter - posCenter;
+				var tangentLength = tangentDirection.Length;
+				var tangentOffset = WVec.Zero;
+				if (tangentLength != 0)
+					tangentOffset = new WVec(-tangentDirection.Y, tangentDirection.X, 0) * turnRadius / tangentLength;
+
+				// TODO: correctly handle CCW <-> CW turns
+				if (tangentOffset.X > 0)
+					tangentOffset = -tangentOffset;
+
+				var w1 = posCenter + tangentOffset;
+				var w2 = approachCenter + tangentOffset;
+				var w3 = approachStart;
+
+				turnRadius = Fly.CalculateTurnRadius(aircraft.Info.Speed, aircraft.Info.TurnSpeed);
+
+				// Move along approach trajectory.
+				QueueChild(self, new Fly(self, Target.FromPos(w1), WDist.Zero, new WDist(turnRadius * 3)), true);
+				QueueChild(self, new Fly(self, Target.FromPos(w2)), true);
+
+				// Fix a problem when the airplane is sent to land near the landing cell
+				QueueChild(self, new Fly(self, Target.FromPos(w3), WDist.Zero, new WDist(turnRadius / 2)), true);
+				finishedApproach = true;
+				return this;
 			}

 			if (!landingInitiated)
 			{
-				var landingCell = !aircraft.Info.VTOL ? self.World.Map.CellContaining(target.CenterPosition + offset) : self.Location;
-				if (!aircraft.CanLand(landingCell, target.Actor))
+				var blockingCells = clearCells.Append(landingCell);
+
+				if (!aircraft.CanLand(blockingCells, target.Actor))
 				{
 					// Maintain holding pattern.
-					if (!aircraft.Info.CanHover)
+					if (aircraft.Info.CanHover)
+						QueueChild(self, new Wait(25), true);
+					else
 						QueueChild(self, new FlyCircle(self, 25), true);

-					self.NotifyBlocker(landingCell);
+					self.NotifyBlocker(blockingCells);
+					finishedApproach = false;
 					return this;
 				}

+				if (aircraft.Info.LandingSounds.Length > 0)
+					Game.Sound.Play(SoundType.World, aircraft.Info.LandingSounds, self.World, aircraft.CenterPosition);
+
 				aircraft.AddInfluence(landingCell);
 				aircraft.EnteringCell(self);
 				landingInitiated = true;
 			}

-			var altitude = self.World.Map.DistanceAboveTerrain(self.CenterPosition);
-			var landAltitude = self.World.Map.DistanceAboveTerrain(target.CenterPosition + offset) + aircraft.LandAltitude;
-
-			if (!soundPlayed && aircraft.Info.LandingSounds.Length > 0 && altitude != landAltitude)
-			{
-				Game.Sound.Play(SoundType.World, aircraft.Info.LandingSounds, self.World, aircraft.CenterPosition);
-				soundPlayed = true;
-			}
-
-			// For VTOLs we assume we've already arrived at the target location and just need to move downward
+			// Final descent.
 			if (aircraft.Info.VTOL)
 			{
+				var landAltitude = self.World.Map.DistanceAboveTerrain(targetPosition) + aircraft.LandAltitude;
 				if (Fly.VerticalTakeOffOrLandTick(self, aircraft, aircraft.Facing, landAltitude))
 					return this;

 				return NextActivity;
 			}

-			var d = (target.CenterPosition + offset) - self.CenterPosition;
+			var d = targetPosition - pos;

 			// The next move would overshoot, so just set the final position
 			var move = aircraft.FlyStep(aircraft.Facing);
 			if (d.HorizontalLengthSquared < move.HorizontalLengthSquared)
 			{
 				var landingAltVec = new WVec(WDist.Zero, WDist.Zero, aircraft.LandAltitude);
-				aircraft.SetPosition(self, target.CenterPosition + offset + landingAltVec);
+				aircraft.SetPosition(self, targetPosition + landingAltVec);
 				return NextActivity;
 			}

-			var landingAlt = self.World.Map.DistanceAboveTerrain(target.CenterPosition + offset) + aircraft.LandAltitude;
+			var landingAlt = self.World.Map.DistanceAboveTerrain(targetPosition) + aircraft.LandAltitude;
 			Fly.FlyTick(self, aircraft, d.Yaw.Facing, landingAlt);

 			return this;