Replace cheat-detection teleport with server reconciliation

The old PUNKBUSTER check compared client-reported position to server
position and snapped the player back when latency made them diverge,
which felt like getting teleported under any real network conditions.

Replaces that with proper client-side prediction + reconciliation:
client tags each input with a sequence number and keeps an input
buffer; server tracks the last processed sequence and reports its
authoritative position via a per-user inputAck alongside each
worldUpdate. The client only corrects when the actual disagreement
exceeds what the unacked input time can explain — so steady-state
movement runs purely on local physics, and only genuine unexpected
events (collisions, being hit) trigger a smooth blend toward the
server state.

Includes adaptive threshold scaling so high-latency sessions don't
false-positive corrections during normal running.

.gitignore

@@ -5,3 +5,6 @@ lab/audio/
 lab/filter/
 static/items/rube/*-backups
 build/
+runs/
+poc-webrtc/runs/
+poc-webrtc/node_modules/

app/Game/Channel/Control/PlayerController.js

@@ -1,17 +1,17 @@
 define([
 	"Game/Core/Control/PlayerController",
 	"Lib/Utilities/NotificationCenter",
-    "Lib/Utilities/Protocol/Parser",
+    "Lib/Utilities/Protocol/Parser"
-    "Game/Config/Settings"
 ],
 
-function(Parent, nc, Parser, Settings) {
+function(Parent, nc, Parser) {
 
     "use strict";
  
     function PlayerController(player) {
 
     	Parent.call(this, player);
+        this._lastProcessedSeq = 0;
     }
 
     PlayerController.prototype = Object.create(Parent.prototype);
@@ -30,7 +30,14 @@ function(Parent, nc, Parser, Settings) {
         }
 
         for (var command in message) {
-            this[command].call(this, message[command]);
+            var commandOptions = message[command];
+
+            // Track sequence number from client input commands
+            if (commandOptions && typeof commandOptions === 'object' && commandOptions._seq !== undefined) {
+                this._lastProcessedSeq = commandOptions._seq;
+            }
+
+            this[command].call(this, commandOptions);
         }
     };
 
@@ -45,36 +52,6 @@ function(Parent, nc, Parser, Settings) {
         this.player.suicide();
     };
 
-    PlayerController.prototype.mePositionStateOverride = function(update) {
-
-        if(!this.player.isSpawned()) {
-            // if someone still falls but is dead on the server already
-            return; 
-        }
-
-        var difference = {
-            x: Math.abs(update.p.x - this.player.doll.body.GetPosition().x),
-            y: Math.abs(update.p.y - this.player.doll.body.GetPosition().y)
-        };
-
-        if(difference.x < Settings.PUNKBUSTER_DIFFERENCE_METERS &&
-           difference.y < Settings.PUNKBUSTER_DIFFERENCE_METERS) {
-            this.player.doll.updatePositionState(update);
-        } else {
-            // HARD UPDATE FOR SELF
-            console.log(this.player.user.options.nickname + " is cheating.");
-
-            var body = this.player.doll.body;
-
-            var options = {
-                p: body.GetPosition(),
-                lv: body.GetLinearVelocity()
-            };
-
-            nc.trigger(nc.ns.channel.to.client.user.gameCommand.send + this.player.id, "positionStateReset", options);
-        }
-    };
-
     return PlayerController;
  
 });

app/Game/Channel/GameController.js

@@ -120,6 +120,23 @@ function (Parent, PhysicsEngine, Settings, requestAnimFrame, nc, Box2D, Player,
             nc.trigger(nc.ns.channel.to.client.gameCommand.broadcast, "worldUpdate", update);
         }
 
+        // Send per-user input acknowledgments for server reconciliation
+        for (var id in this.players) {
+            var player = this.players[id];
+            if (player.isSpawned() && player.playerController._lastProcessedSeq > 0) {
+                var body = player.doll.body;
+                nc.trigger(
+                    nc.ns.channel.to.client.user.gameCommand.send + id,
+                    "inputAck",
+                    {
+                        seq: player.playerController._lastProcessedSeq,
+                        p: { x: body.GetPosition().x, y: body.GetPosition().y },
+                        lv: { x: body.GetLinearVelocity().x, y: body.GetLinearVelocity().y }
+                    }
+                );
+            }
+        }
+
         this.worldUpdateTimeout = setTimeout(this.updateWorld.bind(this), Settings.NETWORK_UPDATE_INTERVAL);
     };
 

app/Game/Channel/GameObjects/Doll.js

@@ -2,11 +2,10 @@ define([
 	"Game/Core/GameObjects/Doll",
     "Game/Channel/GameObjects/Item",
     "Lib/Vendor/Box2D",
-    "Lib/Utilities/NotificationCenter",
+    "Lib/Utilities/NotificationCenter"
-    "Lib/Utilities/Assert"
 ],
 
-function (Parent, Item, Box2D, nc, Assert) {
+function (Parent, Item, Box2D, nc) {
 
 	"use strict";
  
@@ -93,16 +92,6 @@ function (Parent, Item, Box2D, nc, Assert) {
         }
     };
 
-    Doll.prototype.updatePositionState = function(update) {
-        if(!this.isAnotherPlayerNearby()) {
-            Assert.number(update.p.x, update.p.y);
-            Assert.number(update.lv.x, update.lv.y);
-            this.body.SetAwake(true);
-            this.body.SetPosition(update.p);
-            this.body.SetLinearVelocity(update.lv);
-        }
-    };
-
     Doll.prototype.getUpdateData = function(getSleeping) {
 
         var updateData = Parent.prototype.getUpdateData.call(this, getSleeping);

app/Game/Client/Control/PlayerController.js

@@ -14,6 +14,7 @@ function (Parent, nc, KeyboardAndMouse, Gamepad, pointerLockManager) {
 
         Parent.call(this, me);
 
+        this._inputSeq = 0;
         this.keyboardAndMouse = new KeyboardAndMouse(this);
         this.gamepad = new Gamepad(this);
     }
@@ -26,34 +27,48 @@ function (Parent, nc, KeyboardAndMouse, Gamepad, pointerLockManager) {
         this.gamepad.update();
     };
 
+    PlayerController.prototype._recordAndSend = function(command) {
+        this._inputSeq++;
+        if (this.player.doll && this.player.doll.body) {
+            var vel = this.player.doll.body.GetLinearVelocity();
+            this.player.inputBuffer.add({
+                seq: this._inputSeq,
+                timestamp: Date.now(),
+                vx: vel.x,
+                vy: vel.y
+            });
+        }
+        nc.trigger(nc.ns.client.to.server.gameCommand.send, command, {_seq: this._inputSeq});
+    };
+
     PlayerController.prototype.moveLeft = function () {
         if (!this.isPlayerInputAllowed()) return;
         Parent.prototype.moveLeft.call(this);
-        nc.trigger(nc.ns.client.to.server.gameCommand.send, 'moveLeft');
+        this._recordAndSend('moveLeft');
     }
 
     PlayerController.prototype.moveRight = function () {
         if (!this.isPlayerInputAllowed()) return;
         Parent.prototype.moveRight.call(this);
-        nc.trigger(nc.ns.client.to.server.gameCommand.send, 'moveRight');
+        this._recordAndSend('moveRight');
     }
 
     // always allow to stop, to prevent endless running
     PlayerController.prototype.stop = function () {
         Parent.prototype.stop.call(this);
-        nc.trigger(nc.ns.client.to.server.gameCommand.send, 'stop');
+        this._recordAndSend('stop');
     }
 
     PlayerController.prototype.jump = function () {
         if (!this.isPlayerInputAllowed()) return;
         Parent.prototype.jump.call(this);
-        nc.trigger(nc.ns.client.to.server.gameCommand.send, 'jump');
+        this._recordAndSend('jump');
     }
 
     // always allow to stop.
     PlayerController.prototype.jumpStop = function () {
         Parent.prototype.jumpStop.call(this);
-        nc.trigger(nc.ns.client.to.server.gameCommand.send, 'jumpStop');
+        this._recordAndSend('jumpStop');
     }
 
     PlayerController.prototype.setXY = function(x, y) {

app/Game/Client/GameController.js

@@ -52,7 +52,6 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
 
         if(this.me) {
             this.me.update();
-            this.mePositionStateOverride();
         }
 
         nc.trigger(nc.ns.client.game.events.render);
@@ -61,12 +60,32 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
         domController.fpsStep();
     };
 
-    GameController.prototype.mePositionStateOverride = function() {   
+    GameController.prototype.onInputAck = function(ackData) {
-        if(this.me.isPositionStateOverrideNeeded()) {
+        if (!this.me || !this.me.doll) return;
-            nc.trigger(
+
-                nc.ns.client.to.server.gameCommand.send, 
+        this.me.inputBuffer.acknowledgeUpTo(ackData.seq);
-                "mePositionStateOverride", 
+
-                this.me.getPositionStateOverride()
+        var currentPos = this.me.doll.body.GetPosition();
+        var diffX = Math.abs(ackData.p.x - currentPos.x);
+        var diffY = Math.abs(ackData.p.y - currentPos.y);
+
+        // Scale the acceptable drift by how many inputs the server
+        // hasn't processed yet. More unacked time = more expected drift.
+        var unacked = this.me.inputBuffer.getUnacknowledged();
+        var expectedDrift = 0;
+        if (unacked.length > 0) {
+            var unackedTime = (Date.now() - unacked[0].timestamp) / 1000;
+            expectedDrift = unackedTime * Settings.RUN_SPEED;
+        }
+
+        var threshold = Settings.RECONCILIATION_THRESHOLD + expectedDrift;
+
+        // Only correct when the error exceeds what latency can explain —
+        // meaning something unexpected happened (collision, being hit, etc.)
+        if (diffX > threshold || diffY > threshold) {
+            this.me.applyReconciliation(
+                ackData.p.x, ackData.p.y,
+                ackData.lv.x, ackData.lv.y
             );
         }
     };
@@ -108,36 +127,15 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
     };
 
 
-    /*
-
-    TODO : 
-    - remove this 
-    - overwrite setUpdateData inside client / Me with an empty function
-
-    GameController.prototype.onWorldUpdateGameObject = function(body, gameObject, update) {
-        if(gameObject === this.me.doll) {
-            this.me.setLastServerPositionState(update);
-            if(!this.me.acceptPositionStateUpdateFromServer()) {
-                return; // this is to ignore own doll updates from world update 
-            }
-        } 
-
-        Parent.prototype.onWorldUpdateGameObject.call(this, body, gameObject, update);
-    };
-    */
-
     GameController.prototype.onRemoveGameObject = function(options) {
 
     };
 
+    // Own doll position is handled by onInputAck reconciliation, not worldUpdate
     GameController.prototype.updateGameObject = function (gameObject, gameObjectUpdate) {
-        if(gameObject === this.me.doll) {
+        if (gameObject === this.me.doll) {
-            this.me.setLastServerPositionState(gameObjectUpdate);
+            return;
-            if(!this.me.acceptPositionStateUpdateFromServer()) {
-                return; // this is to ignore own doll updates from world update 
         }
-        } 
-
         Parent.prototype.updateGameObject.call(this, gameObject, gameObjectUpdate);
     }
 
@@ -167,6 +165,10 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
         var player = this.players[playerId];
         player.spawn(x, y);
 
+        if (player === this.me) {
+            this.me.inputBuffer.clear();
+        }
+
         if(options.holdingItemUid) {
             this.onHandActionResponse({
                 itemUid: options.holdingItemUid,
@@ -222,6 +224,10 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
         var killedByPlayer = this.players[options.killedByPlayerId];
         player.kill(killedByPlayer, options.ragDollId);
 
+        if (player === this.me) {
+            this.me.inputBuffer.clear();
+        }
+
         nc.trigger(nc.ns.client.view.gameStats.kill, {
             victim: {
                 name: player.user.options.nickname,
@@ -235,10 +241,6 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
         });
     };
 
-    GameController.prototype.onPositionStateReset = function(options) {
-        this.me.resetPositionState(options);
-    };
-
     GameController.prototype.loadLevel = function (path) {
         Parent.prototype.loadLevel.call(this, path);
     };
@@ -257,6 +259,7 @@ function (Parent, Box2D, PhysicsEngine, ViewManager, PlayerController, nc, reque
 
     GameController.prototype.endRound = function() {
         this.me.setInBetweenRounds(true);
+        this.me.inputBuffer.clear();
         this.toggleGameStats(true);
     };
 

app/Game/Client/InputBuffer.js

@@ -0,0 +1,37 @@
+define([
+],
+
+function () {
+
+    "use strict";
+
+    var MAX_BUFFER_SIZE = 300;
+
+    function InputBuffer() {
+        this._buffer = [];
+    }
+
+    InputBuffer.prototype.add = function(entry) {
+        this._buffer.push(entry);
+        if (this._buffer.length > MAX_BUFFER_SIZE) {
+            this._buffer.shift();
+        }
+    };
+
+    InputBuffer.prototype.acknowledgeUpTo = function(seq) {
+        while (this._buffer.length > 0 && this._buffer[0].seq <= seq) {
+            this._buffer.shift();
+        }
+    };
+
+    InputBuffer.prototype.getUnacknowledged = function() {
+        return this._buffer;
+    };
+
+    InputBuffer.prototype.clear = function() {
+        this._buffer = [];
+    };
+
+    return InputBuffer;
+
+});

app/Game/Client/Me.js

@@ -4,9 +4,10 @@ define([
     "Lib/Utilities/NotificationCenter",
     "Lib/Utilities/Assert",
     "Game/Client/Control/PlayerController",
+    "Game/Client/InputBuffer",
 ],
 
-function (Parent, Settings, nc, Assert, PlayerController) {
+function (Parent, Settings, nc, Assert, PlayerController, InputBuffer) {
 
 	"use strict";
  
@@ -19,12 +20,7 @@ function (Parent, Settings, nc, Assert, PlayerController) {
             y: 0
         };
 
-    	this.lastServerPositionState = {
+        this.inputBuffer = new InputBuffer();
-    		p: {
-    			x: 0,
-    			y: 0
-    		}
-    	};
 
         this.arrowMesh = null;
         this.createAndAddArrow();
@@ -49,50 +45,25 @@ function (Parent, Settings, nc, Assert, PlayerController) {
         };
     };
  
-    Me.prototype.setLastServerPositionState = function(update) {
+    Me.prototype.applyReconciliation = function(x, y, vx, vy) {
-    	this.lastServerPositionState = update;
+        var currentPos = this.doll.body.GetPosition();
-    };
+        var diffX = x - currentPos.x;
+        var diffY = y - currentPos.y;
+        var distance = Math.sqrt(diffX * diffX + diffY * diffY);
 
-    // Checks if client should send out its position to server
+        if (distance > Settings.RECONCILIATION_SNAP_THRESHOLD) {
-	Me.prototype.isPositionStateOverrideNeeded = function() {
+            // Large error — snap immediately (server-side teleport, respawn, etc.)
-
+            this.doll.body.SetPosition({x: x, y: y});
-		if(!this.doll) {
+        } else {
-            return false;
+            // Small error — blend toward reconciled position
+            var factor = Settings.RECONCILIATION_BLEND_FACTOR;
+            this.doll.body.SetPosition({
+                x: currentPos.x + diffX * factor,
+                y: currentPos.y + diffY * factor
+            });
         }
 
-        if(this.doll.isAnotherPlayerNearby()) {
+        this.doll.body.SetLinearVelocity({x: vx, y: vy});
-            return false;
-        }
-
-		var difference = {
-			x: Math.abs(this.lastServerPositionState.p.x - this.doll.body.GetPosition().x),
-			y: Math.abs(this.lastServerPositionState.p.y - this.doll.body.GetPosition().y)
-		};
-
-		if(difference.x > Settings.ME_STATE_MAX_DIFFERENCE_METERS ||
-            difference.y > Settings.ME_STATE_MAX_DIFFERENCE_METERS) {
-			return true;
-		}
-    	return false;
-    };
-
-    Me.prototype.getPositionStateOverride = function() {
-    	return {
-    		p: this.doll.body.GetPosition().Copy(),
-    		lv: this.doll.body.GetLinearVelocity().Copy()
-    	};
-    };
-
-    Me.prototype.acceptPositionStateUpdateFromServer = function() {
-        // gamecontroller should accept  me's doll update only when another players doll is nearby.
-        return this.doll.isAnotherPlayerNearby();
-    };
-
-    Me.prototype.resetPositionState = function(options) {
-        Assert.number(options.p.x, options.p.y);
-        Assert.number(options.lv.x, options.lv.y);
-        this.doll.body.SetPosition(options.p);
-        this.doll.body.SetLinearVelocity(options.lv);
     };
 
     Me.prototype.createAndAddArrow = function() {

app/Game/Config/Settings.js

@@ -93,9 +93,10 @@ function () {
         CHANNEL_DEFAULT_LEVELS: ["debug"],
         CHANNEL_RECORD_SESSION: false,
 
-        // ME STATE
+        // RECONCILIATION
-        ME_STATE_MAX_DIFFERENCE_METERS: 1,
+        RECONCILIATION_THRESHOLD: 1,
-        PUNKBUSTER_DIFFERENCE_METERS: 1
+        RECONCILIATION_SNAP_THRESHOLD: 5.0,
+        RECONCILIATION_BLEND_FACTOR: 0.2
     };
 
     Settings.TILE_RATIO = Settings.ORIGINAL_TILE_SIZE / Settings.TILE_SIZE;