127 lines
4.7 KiB
C#
127 lines
4.7 KiB
C#
#region Copyright & License Information
|
|
/*
|
|
* Copyright 2007-2021 The OpenRA Developers (see AUTHORS)
|
|
* This file is part of OpenRA, which is free software. It is made
|
|
* available to you 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. For more
|
|
* information, see COPYING.
|
|
*/
|
|
#endregion
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.Linq;
|
|
using OpenRA.Mods.Common.Pathfinder;
|
|
using OpenRA.Traits;
|
|
|
|
namespace OpenRA.Mods.Common.Traits
|
|
{
|
|
[TraitLocation(SystemActors.World)]
|
|
[Desc("Calculates routes for mobile units with locomotors based on the A* search algorithm.", " Attach this to the world actor.")]
|
|
public class PathFinderInfo : TraitInfo, Requires<LocomotorInfo>
|
|
{
|
|
public override object Create(ActorInitializer init)
|
|
{
|
|
return new PathFinder(init.World);
|
|
}
|
|
}
|
|
|
|
public class PathFinder : IPathFinder
|
|
{
|
|
public static readonly List<CPos> NoPath = new List<CPos>(0);
|
|
|
|
readonly World world;
|
|
|
|
public PathFinder(World world)
|
|
{
|
|
this.world = world;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Calculates a path for the actor from multiple possible sources to target.
|
|
/// Returned path is *reversed* and given target to source.
|
|
/// The shortest path between a source and the target is returned.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// Searches that provide a multiple source cells are slower than those than provide only a single source cell,
|
|
/// as optimizations are possible for the single source case. Use searches from multiple source cells
|
|
/// sparingly.
|
|
/// </remarks>
|
|
public List<CPos> FindUnitPathToTargetCell(
|
|
Actor self, IEnumerable<CPos> sources, CPos target, BlockedByActor check,
|
|
Func<CPos, int> customCost = null,
|
|
Actor ignoreActor = null,
|
|
bool laneBias = true)
|
|
{
|
|
var sourcesList = sources.ToList();
|
|
if (sourcesList.Count == 0)
|
|
return NoPath;
|
|
|
|
var locomotor = GetLocomotor(self);
|
|
|
|
// If the target cell is inaccessible, bail early.
|
|
var inaccessible =
|
|
!world.Map.Contains(target) ||
|
|
!locomotor.CanMoveFreelyInto(self, target, check, ignoreActor) ||
|
|
(!(customCost is null) && customCost(target) == PathGraph.PathCostForInvalidPath);
|
|
if (inaccessible)
|
|
return NoPath;
|
|
|
|
// When searching from only one source cell, some optimizations are possible.
|
|
if (sourcesList.Count == 1)
|
|
{
|
|
var source = sourcesList[0];
|
|
|
|
// For adjacent cells on the same layer, we can return the path without invoking a full search.
|
|
if (source.Layer == target.Layer && (source - target).LengthSquared < 3)
|
|
{
|
|
if (!world.Map.Contains(source))
|
|
return NoPath;
|
|
return new List<CPos>(2) { target, source };
|
|
}
|
|
|
|
// With one starting point, we can use a bidirectional search.
|
|
using (var fromTarget = PathSearch.ToTargetCell(
|
|
world, locomotor, self, new[] { target }, source, check, ignoreActor: ignoreActor))
|
|
using (var fromSource = PathSearch.ToTargetCell(
|
|
world, locomotor, self, new[] { source }, target, check, ignoreActor: ignoreActor, inReverse: true))
|
|
return PathSearch.FindBidiPath(fromTarget, fromSource);
|
|
}
|
|
|
|
// With multiple starting points, we can only use a unidirectional search.
|
|
using (var search = PathSearch.ToTargetCell(
|
|
world, locomotor, self, sourcesList, target, check, customCost, ignoreActor, laneBias))
|
|
return search.FindPath();
|
|
}
|
|
|
|
/// <summary>
|
|
/// Calculates a path for the actor from multiple possible sources, whilst searching for an acceptable target.
|
|
/// Returned path is *reversed* and given target to source.
|
|
/// The shortest path between a source and a discovered target is returned.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// Searches with this method are slower than <see cref="FindUnitPathToTargetCell"/> due to the need to search for
|
|
/// and discover an acceptable target cell. Use this search sparingly.
|
|
/// </remarks>
|
|
public List<CPos> FindUnitPathToTargetCellByPredicate(
|
|
Actor self, IEnumerable<CPos> sources, Func<CPos, bool> targetPredicate, BlockedByActor check,
|
|
Func<CPos, int> customCost = null,
|
|
Actor ignoreActor = null,
|
|
bool laneBias = true)
|
|
{
|
|
// With no pre-specified target location, we can only use a unidirectional search.
|
|
using (var search = PathSearch.ToTargetCellByPredicate(
|
|
world, GetLocomotor(self), self, sources, targetPredicate, check, customCost, ignoreActor, laneBias))
|
|
return search.FindPath();
|
|
}
|
|
|
|
static Locomotor GetLocomotor(Actor self)
|
|
{
|
|
// PERF: This PathFinder trait requires the use of Mobile, so we can be sure that is in use.
|
|
// We can save some performance by avoiding querying for the Locomotor trait and retrieving it from Mobile.
|
|
return ((Mobile)self.OccupiesSpace).Locomotor;
|
|
}
|
|
}
|
|
}
|