workadventure/back/src/Model/PositionNotifier.ts
2020-09-25 15:25:06 +02:00

133 lines
4.9 KiB
TypeScript

/**
* Tracks the position of every player on the map, and sends notifications to the players interested in knowing about the move
* (i.e. players that are looking at the zone the player is currently in)
*
* Internally, the PositionNotifier works with Zones. A zone is a square area of a map.
* Each player is in a given zone, and each player tracks one or many zones (depending on the player viewport)
*
* The PositionNotifier is important for performance. It allows us to send the position of players only to a restricted
* number of players around the current player.
*/
import {EntersCallback, LeavesCallback, MovesCallback, Zone} from "./Zone";
import {PointInterface} from "_Model/Websocket/PointInterface";
import {User} from "_Model/User";
import {ViewportInterface} from "_Model/Websocket/ViewportMessage";
import {Movable} from "_Model/Movable";
import {PositionInterface} from "_Model/PositionInterface";
interface ZoneDescriptor {
i: number;
j: number;
}
export class PositionNotifier {
// TODO: we need a way to clean the zones if noone is in the zone and noone listening (to free memory!)
private zones: Zone[][] = [];
constructor(private zoneWidth: number, private zoneHeight: number, private onUserEnters: EntersCallback, private onUserMoves: MovesCallback, private onUserLeaves: LeavesCallback) {
}
private getZoneDescriptorFromCoordinates(x: number, y: number): ZoneDescriptor {
return {
i: Math.floor(x / this.zoneWidth),
j: Math.floor(y / this.zoneHeight),
}
}
/**
* Sets the viewport coordinates.
* Returns the list of new users to add
*/
public setViewport(user: User, viewport: ViewportInterface): Movable[] {
if (viewport.left > viewport.right || viewport.top > viewport.bottom) {
console.warn('Invalid viewport received: ', viewport);
return [];
}
const oldZones = user.listenedZones;
const newZones = new Set<Zone>();
const topLeftDesc = this.getZoneDescriptorFromCoordinates(viewport.left, viewport.top);
const bottomRightDesc = this.getZoneDescriptorFromCoordinates(viewport.right, viewport.bottom);
for (let j = topLeftDesc.j; j <= bottomRightDesc.j; j++) {
for (let i = topLeftDesc.i; i <= bottomRightDesc.i; i++) {
newZones.add(this.getZone(i, j));
}
}
const addedZones = [...newZones].filter(x => !oldZones.has(x));
const removedZones = [...oldZones].filter(x => !newZones.has(x));
let things: Movable[] = [];
for (const zone of addedZones) {
zone.startListening(user);
things = things.concat(Array.from(zone.getThings()))
}
for (const zone of removedZones) {
zone.stopListening(user);
}
return things;
}
public enter(thing: Movable): void {
const position = thing.getPosition();
const zoneDesc = this.getZoneDescriptorFromCoordinates(position.x, position.y);
const zone = this.getZone(zoneDesc.i, zoneDesc.j);
zone.enter(thing, null, position);
}
public updatePosition(thing: Movable, newPosition: PositionInterface, oldPosition: PositionInterface): void {
// Did we change zone?
const oldZoneDesc = this.getZoneDescriptorFromCoordinates(oldPosition.x, oldPosition.y);
const newZoneDesc = this.getZoneDescriptorFromCoordinates(newPosition.x, newPosition.y);
if (oldZoneDesc.i != newZoneDesc.i || oldZoneDesc.j != newZoneDesc.j) {
const oldZone = this.getZone(oldZoneDesc.i, oldZoneDesc.j);
const newZone = this.getZone(newZoneDesc.i, newZoneDesc.j);
// Leave old zone
oldZone.leave(thing, newZone);
// Enter new zone
newZone.enter(thing, oldZone, newPosition);
} else {
const zone = this.getZone(oldZoneDesc.i, oldZoneDesc.j);
zone.move(thing, newPosition);
}
}
public leave(thing: Movable): void {
const oldPosition = thing.getPosition();
const oldZoneDesc = this.getZoneDescriptorFromCoordinates(oldPosition.x, oldPosition.y);
const oldZone = this.getZone(oldZoneDesc.i, oldZoneDesc.j);
oldZone.leave(thing, null);
}
public removeViewport(user: User): void {
// Also, let's stop listening on viewports
for (const zone of user.listenedZones) {
zone.stopListening(user);
}
}
private getZone(i: number, j: number): Zone {
let zoneRow = this.zones[j];
if (zoneRow === undefined) {
zoneRow = new Array<Zone>();
this.zones[j] = zoneRow;
}
let zone = this.zones[j][i];
if (zone === undefined) {
zone = new Zone(this.onUserEnters, this.onUserMoves, this.onUserLeaves, i, j);
this.zones[j][i] = zone;
}
return zone;
}
}