92 lines
3.3 KiB
C#
92 lines
3.3 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2021 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version. For more
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* information, see COPYING.
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*/
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#endregion
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using System.Collections.Generic;
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using OpenRA.Activities;
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using OpenRA.Mods.Common.Traits;
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using OpenRA.Primitives;
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using OpenRA.Traits;
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namespace OpenRA.Mods.Common.Activities
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{
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public class Follow : Activity
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{
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readonly WDist minRange;
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readonly WDist maxRange;
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readonly IMove move;
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readonly Color? targetLineColor;
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Target target;
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Target lastVisibleTarget;
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bool useLastVisibleTarget;
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bool wasMovingWithinRange;
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public Follow(Actor self, in Target target, WDist minRange, WDist maxRange,
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WPos? initialTargetPosition, Color? targetLineColor = null)
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{
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this.target = target;
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this.minRange = minRange;
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this.maxRange = maxRange;
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this.targetLineColor = targetLineColor;
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move = self.Trait<IMove>();
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// The target may become hidden between the initial order request and the first tick (e.g. if queued)
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// Moving to any position (even if quite stale) is still better than immediately giving up
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if ((target.Type == TargetType.Actor && target.Actor.CanBeViewedByPlayer(self.Owner))
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|| target.Type == TargetType.FrozenActor || target.Type == TargetType.Terrain)
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lastVisibleTarget = Target.FromPos(target.CenterPosition);
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else if (initialTargetPosition.HasValue)
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lastVisibleTarget = Target.FromPos(initialTargetPosition.Value);
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}
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public override bool Tick(Actor self)
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{
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if (IsCanceling)
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return true;
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target = target.Recalculate(self.Owner, out var targetIsHiddenActor);
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if (!targetIsHiddenActor && target.Type == TargetType.Actor)
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lastVisibleTarget = Target.FromTargetPositions(target);
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useLastVisibleTarget = targetIsHiddenActor || !target.IsValidFor(self);
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// If we are ticking again after previously sequencing a MoveWithRange then that move must have completed
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// Either we are in range and can see the target, or we've lost track of it and should give up
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if (wasMovingWithinRange && targetIsHiddenActor)
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return true;
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wasMovingWithinRange = false;
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// Target is hidden or dead, and we don't have a fallback position to move towards
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if (useLastVisibleTarget && !lastVisibleTarget.IsValidFor(self))
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return true;
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var pos = self.CenterPosition;
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var checkTarget = useLastVisibleTarget ? lastVisibleTarget : target;
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// We've reached the required range - if the target is visible and valid then we wait
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// otherwise if it is hidden or dead we give up
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if (checkTarget.IsInRange(pos, maxRange) && !checkTarget.IsInRange(pos, minRange))
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return useLastVisibleTarget;
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// Move into range
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wasMovingWithinRange = true;
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QueueChild(move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, targetLineColor));
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return false;
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}
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public override IEnumerable<TargetLineNode> TargetLineNodes(Actor self)
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{
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if (targetLineColor != null)
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yield return new TargetLineNode(useLastVisibleTarget ? lastVisibleTarget : target, targetLineColor.Value);
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}
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}
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}
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