invisioblack/screeps-path

Advanced JPS pathfinder for Screeps

The General's pathfinder

This is a custom pathfinder for use in Screeps. It has support for custom cost functions (see path-room-data.js), can create paths that span several rooms, and is a good deal faster than the built-in pathfinder as well. Under the hood it's using a modified version of jump point search... JPS by design only works on uniform-cost grids, but Screeps' grids are weighted (plain, swamp, and road all cause different values of fatigue) so we need to modify the original algorithm a little bit.

The code itself is fairly well documented, but you won't find any API documentation except for looking at the code yourself.

Getting started:

let path = require('path_');
let WorldPosition = path.WorldPosition;
path.find(
	WorldPosition(Game.creeps.John.pos),
	{ target: WorldPosition(Game.spawns.Spawn1.pos) }
);

This pathfinder uses a replacement for RoomPosition called WorldPosition. Instead of tracking positions by coordinates and a room name, WorldPosition unifies the entire world map into a continuous coordinate plane. This allows us to easily calculate the distance between two positions when they aren't in the same room. You can convert a RoomPosition into a WorldPosition via WorldPosition(rp) and a WorldPosition back via wp.toRoomPosition().

Returned from find is a PathInfo object which keeps around some extra data about the path, like where the roads and swamps are. See path-info.js.

The first time you create a path you will need to have access to all the rooms it touches, but after the pathfinder has seen a room it will remember its terrain and you can search for paths through rooms in which you control no creeps or structures. This data is all stashed in Memory.terrain. See TerrainData in path-room-data.js for more information about that.

You can specify multiple targets by using the targets option parameter, or try findNearest for a replacement of RoomPosition.findClosestByPath with the added bonus of returning the path to whatever it found.