feat: heartbeat/rtt

app/net/client.js

@@ -1,8 +1,9 @@
-import {CLIENT_LATENCY} from '@/util/constants.js';
+import {CLIENT_LATENCY, CLIENT_PREDICTION} from '@/util/constants.js';
 import EventEmitter from '@/util/event-emitter.js';
 
 export default class Client {
   emitter = new EventEmitter();
+  rtt = 0;
   throughput = {$$down: 0, down: 0, $$up: 0, up: 0};
   constructor() {
     setInterval(() => {
@@ -13,6 +14,11 @@ export default class Client {
     }, 250);
   }
   accept(packet) {
+    if ('Heartbeat' === packet.type) {
+      this.rtt = packet.payload.rtt;
+      this.send(packet);
+      return;
+    }
     this.emitter.invoke(packet.type, packet.payload);
   }
   addPacketListener(type, listener) {
@@ -22,7 +28,7 @@ export default class Client {
     this.emitter.removeListener(type, listener);
   }
   send(packet) {
-    if (CLIENT_LATENCY > 0) {
+    if (CLIENT_LATENCY > 0 && !CLIENT_PREDICTION) {
       setTimeout(() => {
         this.transmit(packet);
       }, CLIENT_LATENCY);

app/net/packets/heartbeat.js

@@ -0,0 +1,3 @@
+import Packet from '@/net/packet.js';
+
+export default class Heartbeat extends Packet {}

app/react/components/devtools.jsx

@@ -34,8 +34,9 @@ export default function Devtools({
           <div className={styles.dashboard}>
             <form>
               <div className={styles.engineBar}>
-                <div>{Math.round(((client.throughput.down * 8) / 1024) * 10) / 10}kb/s</div>
-                <div>{Math.round(((client.throughput.up * 8) / 1024) * 10) / 10}kb/s</div>
+                <div>{Math.round(client.rtt * 100) / 100}rtt</div>
+                <div>{Math.round(((client.throughput.down * 8) / 1024) * 10) / 10}kb/s down</div>
+                <div>{Math.round(((client.throughput.up * 8) / 1024) * 10) / 10}kb/s up</div>
               </div>
             </form>
             <pre><code><small>{mainEntityJson}</small></code></pre>

app/server/engine.js

@@ -117,6 +117,24 @@ export default class Engine {
       }
       this.incomingActions.get(connection).push(payload);
     });
+    this.server.addPacketListener('Heartbeat', (connection) => {
+      const playerData = this.connectedPlayers.get(connection);
+      const {distance} = playerData;
+      const now = performance.now();
+      distance.rtt = (now - distance.last) / 1000;
+      playerData.heartbeat = setTimeout(() => {
+        distance.last = performance.now();
+        this.server.send(
+          connection,
+          {
+            type: 'Heartbeat',
+            payload: {
+              rtt: distance.rtt,
+            },
+          },
+        );
+      }, 1000);
+    });
   }
 
   acceptActions() {
@@ -239,18 +257,26 @@ export default class Engine {
     }
     const ecs = this.ecses[entityJson.Ecs.path];
     const entity = ecs.get(await ecs.create(entityJson));
-    entity.Player.id = id
-    this.connectedPlayers.set(
-      connection,
-      {
+    entity.Player.id = id;
+    const playerData = {
+      distance: {last: performance.now(), rtt: 0},
       entity,
       id,
       memory: {
         chunks: new Map(),
         nearby: new Set(),
       },
+    };
+    this.server.send(
+      connection,
+      {
+        type: 'Heartbeat',
+        payload: {
+          rtt: 0,
+        },
       },
     );
+    this.connectedPlayers.set(connection, playerData);
   }
 
   createEcs() {
@@ -264,7 +290,8 @@ export default class Engine {
     }
     this.connectedPlayers.delete(connection);
     this.incomingActions.delete(connection);
-    const {entity, id} = connectedPlayer;
+    const {entity, heartbeat, id} = connectedPlayer;
+    clearTimeout(heartbeat);
     const json = entity.toJSON();
     const ecs = this.ecses[entity.Ecs.path];
     return Promise.all([