From 04a0230248d042e34dbc216bc09ad518441de08f Mon Sep 17 00:00:00 2001
From: cha0s <git@cha0s.io>
Date: Sun, 8 Sep 2024 17:19:59 -0500
Subject: [PATCH] refactor: predictor next to client, smoothing

---
 app/client/local.js     | 23 ++++++++++++-----------
 app/client/predictor.js | 24 ++++++++----------------
 app/server/engine.js    | 17 +++++++++++++++++
 app/util/constants.js   |  2 +-
 4 files changed, 38 insertions(+), 28 deletions(-)

diff --git a/app/client/local.js b/app/client/local.js
index af033fb..0f412b6 100644
--- a/app/client/local.js
+++ b/app/client/local.js
@@ -17,7 +17,13 @@ export default class LocalClient extends Client {
         {type: 'module'},
       );
       this.interpolator.addEventListener('message', (event) => {
-        this.accept(event.data);
+        const packet = event.data;
+        if (CLIENT_PREDICTION) {
+          this.predictor.postMessage([1, packet]);
+        }
+        else {
+          this.accept(packet);
+        }
       });
     }
     if (CLIENT_PREDICTION) {
@@ -35,12 +41,7 @@ export default class LocalClient extends Client {
             break;
           }
           case 1: {
-            if (CLIENT_INTERPOLATION) {
-              this.interpolator.postMessage(packet);
-            }
-            else {
-              this.accept(packet);
-            }
+            this.accept(packet);
             break;
           }
         }
@@ -54,12 +55,12 @@ export default class LocalClient extends Client {
       }
       this.throughput.$$down += event.data.byteLength;
       const packet = decode(event.data);
-      if (CLIENT_PREDICTION) {
-        this.predictor.postMessage([1, packet]);
-      }
-      else if (CLIENT_INTERPOLATION) {
+      if (CLIENT_INTERPOLATION) {
         this.interpolator.postMessage(packet);
       }
+      else if (CLIENT_PREDICTION) {
+        this.predictor.postMessage([1, packet]);
+      }
       else {
         this.accept(packet);
       }
diff --git a/app/client/predictor.js b/app/client/predictor.js
index 79c4d01..bf76267 100644
--- a/app/client/predictor.js
+++ b/app/client/predictor.js
@@ -27,17 +27,8 @@ const Flow = {
   DOWN: 1,
 };
 
-const Stage = {
-  UNACK: 0,
-  ACK: 1,
-  FINISHING: 2,
-  FINISHED: 3,
-};
-
 const actions = new Map();
-
 let ecs = new PredictionEcs({Components, Systems});
-
 let mainEntityId = 0;
 
 function applyClientActions(elapsed) {
@@ -46,7 +37,7 @@ function applyClientActions(elapsed) {
     const {Controlled} = main;
     const finished = [];
     for (const [id, action] of actions) {
-      if (Stage.UNACK === action.stage) {
+      if (0 === action.finished && !action.ack) {
         if (!Controlled.locked) {
           switch (action.action.type) {
             case 'moveUp':
@@ -60,7 +51,7 @@ function applyClientActions(elapsed) {
         }
         action.steps.push(elapsed);
       }
-      if (Stage.FINISHING === action.stage) {
+      if (1 === action.finished) {
         if (!Controlled.locked) {
           switch (action.action.type) {
             case 'moveUp':
@@ -72,9 +63,9 @@ function applyClientActions(elapsed) {
             }
           }
         }
-        action.stage = Stage.FINISHED;
+        action.finished = 2;
       }
-      if (Stage.FINISHED === action.stage) {
+      if (action.ack && 2 === action.finished) {
         action.steps.shift();
         if (0 === action.steps.length) {
           finished.push(id);
@@ -113,13 +104,13 @@ onmessage = async (event) => {
               if (0 === packet.payload.value) {
                 const ack = pending.get(packet.payload.type);
                 const action = actions.get(ack);
-                action.stage = Stage.FINISHING;
+                action.finished = 1;
                 pending.delete(packet.payload.type);
               }
               else {
                 const tx = {
                   action: packet.payload,
-                  stage: Stage.UNACK,
+                  ack: false,finished: 0,
                   steps: [],
                 };
                 packet.payload.ack = Math.random();
@@ -139,11 +130,12 @@ onmessage = async (event) => {
         switch (packet.type) {
           case 'ActionAck': {
             const action = actions.get(packet.payload.ack);
-            action.stage = Stage.ACK;
+            action.ack = true;
             return;
           }
           case 'EcsChange': {
             ecs = new PredictionEcs({Components, Systems});
+            mainEntityId = 0;
             break;
           }
           case 'Tick': {
diff --git a/app/server/engine.js b/app/server/engine.js
index 20d37a6..1d78259 100644
--- a/app/server/engine.js
+++ b/app/server/engine.js
@@ -27,6 +27,7 @@ const textEncoder = new TextEncoder();
 
 export default class Engine {
 
+  ackingActions = new Map();
   connectedPlayers = new Map();
   ecses = {};
   frame = 0;
@@ -250,6 +251,15 @@ export default class Engine {
           }
         }
         if (payload.ack) {
+          if (!this.ackingActions.has(connection)) {
+            this.ackingActions.set(connection, []);
+          }
+          this.ackingActions.get(connection).push({
+            type: 'ActionAck',
+            payload: {
+              ack: payload.ack,
+            },
+          })
           this.server.send(
             connection,
             {
@@ -303,6 +313,7 @@ export default class Engine {
     if (!connectedPlayer) {
       return;
     }
+    this.ackingActions.delete(connection);
     this.connectedPlayers.delete(connection);
     this.incomingActions.delete(connection);
     const {entity, heartbeat, id} = connectedPlayer;
@@ -445,6 +456,12 @@ export default class Engine {
 
   update(elapsed) {
     for (const [connection, {entity}] of this.connectedPlayers) {
+      if (this.ackingActions.has(connection)) {
+        for (const ack of this.ackingActions.get(connection)) {
+          this.server.send(connection, ack);
+        }
+        this.ackingActions.delete(connection);
+      }
       if (!entity) {
         continue;
       }
diff --git a/app/util/constants.js b/app/util/constants.js
index 94d1280..3faa0a1 100644
--- a/app/util/constants.js
+++ b/app/util/constants.js
@@ -17,4 +17,4 @@ export const SERVER_LATENCY = 0;
 
 export const TPS = 60;
 
-export const UPS = 15;
+export const UPS = 30;