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OpenRA/OpenRA.Mods.Common/Traits/World/HierarchicalPathFinderOverlay.cs
RoosterDragon 5a8f91aa21 Add a hierarchical path finder to improve pathfinding performance.
Replaces the existing bi-directional search between points used by the pathfinder with a guided hierarchical search. The old search was a standard A* search with a heuristic of advancing in straight line towards the target. This heuristic performs well if a mostly direct path to the target exists, it performs poorly it the path has to navigate around blockages in the terrain. The hierarchical path finder maintains a simplified, abstract graph. When a path search is performed it uses this abstract graph to inform the heuristic. Instead of moving blindly towards the target, it will instead steer around major obstacles, almost as if it had been provided a map which ensures it can move in roughly the right direction. This allows it to explore less of the area overall, improving performance.

When a path needs to steer around terrain on the map, the hierarchical path finder is able to greatly improve on the previous performance. When a path is able to proceed in a straight line, no performance benefit will be seen. If the path needs to steer around actors on the map instead of terrain (e.g. trees, buildings, units) then the same poor pathfinding performance as before will be observed.
2022-08-03 23:12:42 +02:00

138 lines
4.6 KiB
C#

#region Copyright & License Information
/*
* Copyright 2007-2022 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.Collections.Generic;
using System.Linq;
using OpenRA.Graphics;
using OpenRA.Mods.Common.Commands;
using OpenRA.Mods.Common.Graphics;
using OpenRA.Primitives;
using OpenRA.Traits;
namespace OpenRA.Mods.Common.Traits
{
[TraitLocation(SystemActors.World)]
[Desc("Renders a debug overlay showing the abstract graph of the hierarchical pathfinder. Attach this to the world actor.")]
public class HierarchicalPathFinderOverlayInfo : TraitInfo, Requires<PathFinderInfo>
{
public readonly string Font = "TinyBold";
public readonly Color GroundLayerColor = Color.DarkOrange;
public readonly Color CustomLayerColor = Color.Blue;
public readonly Color GroundToCustomLayerColor = Color.Purple;
public readonly Color AbstractNodeColor = Color.Red;
public override object Create(ActorInitializer init) { return new HierarchicalPathFinderOverlay(this); }
}
public class HierarchicalPathFinderOverlay : IRenderAnnotations, IWorldLoaded, IChatCommand
{
const string CommandName = "hpf";
const string CommandDesc = "toggles the hierarchical pathfinder overlay.";
readonly HierarchicalPathFinderOverlayInfo info;
readonly SpriteFont font;
public bool Enabled { get; private set; }
/// <summary>
/// The Locomotor selected in the UI which the overlay will display.
/// If null, will show the overlays for the currently selected units.
/// </summary>
public Locomotor Locomotor { get; set; }
public HierarchicalPathFinderOverlay(HierarchicalPathFinderOverlayInfo info)
{
this.info = info;
font = Game.Renderer.Fonts[info.Font];
}
void IWorldLoaded.WorldLoaded(World w, WorldRenderer wr)
{
var console = w.WorldActor.TraitOrDefault<ChatCommands>();
var help = w.WorldActor.TraitOrDefault<HelpCommand>();
if (console == null || help == null)
return;
console.RegisterCommand(CommandName, this);
help.RegisterHelp(CommandName, CommandDesc);
}
void IChatCommand.InvokeCommand(string name, string arg)
{
if (name == CommandName)
Enabled ^= true;
}
IEnumerable<IRenderable> IRenderAnnotations.RenderAnnotations(Actor self, WorldRenderer wr)
{
if (!Enabled)
yield break;
var pathFinder = self.Trait<PathFinder>();
var visibleRegion = wr.Viewport.AllVisibleCells;
var locomotors = Locomotor == null
? self.World.Selection.Actors
.Where(a => !a.Disposed)
.Select(a => a.TraitOrDefault<Mobile>()?.Locomotor)
.Where(l => l != null)
.Distinct()
: new[] { Locomotor };
foreach (var locomotor in locomotors)
{
var abstractGraph = pathFinder.GetOverlayDataForLocomotor(locomotor);
// Locomotor doesn't allow movement, nothing to display.
if (abstractGraph == null)
continue;
foreach (var connectionsFromOneNode in abstractGraph)
{
var nodeCell = connectionsFromOneNode.Key;
var srcUv = (PPos)nodeCell.ToMPos(self.World.Map);
foreach (var cost in connectionsFromOneNode.Value)
{
var destUv = (PPos)cost.Destination.ToMPos(self.World.Map);
if (!visibleRegion.Contains(destUv) && !visibleRegion.Contains(srcUv))
continue;
var connection = new WPos[]
{
self.World.Map.CenterOfSubCell(cost.Destination, SubCell.FullCell),
self.World.Map.CenterOfSubCell(nodeCell, SubCell.FullCell),
};
// Connections on the ground layer given in ground color.
// Connections on any custom layers given in custom color.
// Connections that allow a transition between layers given in transition color.
Color lineColor;
if (nodeCell.Layer == 0 && cost.Destination.Layer == 0)
lineColor = info.GroundLayerColor;
else if (nodeCell.Layer == cost.Destination.Layer)
lineColor = info.CustomLayerColor;
else
lineColor = info.GroundToCustomLayerColor;
yield return new TargetLineRenderable(connection, lineColor, 1, 2);
var centerCell = new CPos(
(cost.Destination.X + nodeCell.X) / 2,
(cost.Destination.Y + nodeCell.Y) / 2);
var centerPos = self.World.Map.CenterOfSubCell(centerCell, SubCell.FullCell);
yield return new TextAnnotationRenderable(font, centerPos, 0, lineColor, cost.Cost.ToString());
}
}
}
}
bool IRenderAnnotations.SpatiallyPartitionable => false;
}
}