NesCafe62/screeps-flow-field

FlowField JavaScript implementation. Generally built for use in screeps game

FlowField JavaScript implementation. Generally built for use in screeps game.

Installation

Copy flowField.js into your screeps branch directory.

Usage

const FlowField = require('flowField');
// require('flowField'); - or just like that if you keep registered FlewField class as global

// basic usage
const flowField = new FlowField(50, 50, {directions: true});

// define array of sources/targets (supports multiple sources)
const sources = [
	{x: 25, y: 25, cost: 0} // cost - initial cost. It is optional, by default will be 0
];

// if want to use costMatrix
const matrix = new PathFinder.CostMatrix();

// if want to use room terrain
const terrain = new Room.Terrain(roomName);
const terrainCost = {
	0: 1, // plainCost
	[TERRAIN_MASK_SWAMP]: 5, // swampCost
	[TERRAIN_MASK_WALL]: 255,
	[TERRAIN_MASK_WALL | TERRAIN_MASK_SWAMP]: 255,
};
const costCallback = (x, y) => {
	// use value from CostMatrix
	return matrix.get(x, y);
	
	// or use value from terrain
	// return terrainCost[terrain.get(x, y)];
};
const maxCost = 255;

// run flowField generation (can run multiple times with different callbacks and sources. data will be cleared before run)
flowField.generate(
	// array of sources
	sources,
	
	// cost callback for terrain data. 255 or larger values treated as unpathable
	costCallback,
	
	// max cost (will not propagate further from tiles that reach this cost or higher).
	// optional, by default sets to 255 or 65535 (if option uint16 is true)
	maxCost
);

const direction = getDirection(x, y); // get direction for any given coords (if directions option set to true)
const distance = getDistance(x, y); // get distance for any given coords

Options

uint16

Default: false

Sets distance array type as Uint16Array (instead of Uint8Array). Can store distance up to 65535 instead of just 255. Use for potential large costs values or for large flowFields.

const flowField = new FlowField(50, 50, {uint16: true});

// larger size flowField
const flowField2 = new FlowField(147, 147, {uint16: true});

directions

Default: false

Set to true if want to use directions (retreived via getDirection(x, y)). By default it's disabled.

const flowField = new FlowField(50, 50, {directions: true});
flowField.generate(/* ... */);

const direction = getDirection(x, y);

Visualize FlowFIeld

const DIRECTION_TO_OFFSET = [
	[0, 0],
	[0, -1],
	[1, -1],
	[1, 0],
	[1, 1],
	[0, 1],
	[-1, 1],
	[-1, 0],
	[-1, -1],
];

const visual = new RoomVisual(roomName);

// visualize directions (only if option 'directions' was set to true)
for (let x = 1; x < 49; x++) {
	for (let y = 1; y < 49; y++) {
		const direction = flowField.getDirection(x, y);
		if (direction > 0) {
			const [dx, dy] = DIRECTION_TO_OFFSET[direction];
			visual.line(x, y, x + 0.4 * dx, y + 0.4 * dy, {color: 'white', width: 0.1, opacity: 0.6});
		}
	}
}

// visualize distance (pick on or the other unless they will visually interfere)
const maxCost = 255; // can change this value
for (let x = 1; x < 49; x++) {
	for (let y = 1; y < 49; y++) {
		const value = flowField.getDistance(x, y);
		if (value < 255) {
			const hue = Math.floor(360 * value / maxCost);
			visual.circle(x, y, {radius: 0.2, fill: `hsl(${hue}, 100%, 50%)`, opacity: 0.6});
		}
	}
}