Minor fix.

ConcerningEdgeCases.md

@@ -47,3 +47,23 @@ renderFrameId             |   toApplyInputFrameId
 ..., ..., ..., 368        |   90
 369, 370, 371, 372        |   91
 373, 374, 375, ...        |   92      
+
+# Would using UDP instead of TCP yield better synchronization performance?
+Yes, but with non-trivial efforts.
+
+## Neat advantage using UDP 
+Let's check an actual use case. As soon as an inputFrame becomes all-confirmed, the server should downsync it to all active players -- and upon reception loss of the packet containing this "all-confirmed downsync inputFrame" to a certain player, the server MUST retransmit another packet containing the same inputFrame to that player. 
+
+To apply UDP on this use case, additional `ack & retransmission mechanism` would be required, which is a moderately difficult task -- don't just pick a 3rd party lib using TCP flow-control alike `sliding window mechanism`, e.g. [RUDP](https://www.geeksforgeeks.org/reliable-user-datagram-protocol-rudp/)! Here's why. 
+
+Assume that the server is downsyncing `sequence of packets[#1, #2, #3, #4, #5, #6, #7, #8, #9, #10]`, when using TCP we get the advantage that each active player is guaranteed to receive that same sequence in the same order -- however in a bad, lossy network when `packet#2` got lost several times for a certain player whose reception window size is just 5, it has to wait for the arrival of `packet#2` at `[_, #3, #4, #5, #6]`, thus unable to process `[#7, #8, #9, #10]` which could contain `unpredictable inputFrame` while `#2` being `correct prediction` for that player.   
+
+That's so neat but still an advantage for using UDP! Yet if the TCP flow-control alike `sliding window mechanism` is employed on UDP, such advantage'd be compromised. 
+
+To summarize, if UDP is used we need 
+- an `ack & retransmission mechanism` built on top of it to guarantee reception of critical packets for active players, and 
+- reception order is not necessary to be reserved (mimic [markConfirmationIfApplicable](https://github.com/genxium/DelayNoMore/blob/v0.9.14/battle_srv/models/room.go#L1085) to maintain `lastAllConfirmedInputFrameId`), but 
+- TCP flow-control alike `sliding window mechanism` should be avoided to gain advantage over TCP. 
+
+## Additional hassles to care about using UDP
+When using UDP, it's also necessary to verify authorization of each incoming packet, e.g. by simple time limited symmetric key, due to being connectionless.

README.md

@@ -1,6 +1,6 @@
 # Preface 
 
-This project is a demo for a websocket-based rollback netcode inspired by [GGPO](https://github.com/pond3r/ggpo/blob/master/doc/README.md).
+This project is a demo for a websocket-based rollback netcode inspired by [GGPO](https://github.com/pond3r/ggpo/blob/master/doc/README.md). As lots of feedbacks ask for a discussion on using UDP instead, I tried to summarize my personal opinion about it in [ConcerningEdgeCases](./ConcerningEdgeCases.md) -- not necessarily correct but that's indeed a question to face :)
 
 The following video is recorded over INTERNET using an input delay of 4 frames and it feels SMOOTH when playing! Please also checkout [this demo video](https://pan.baidu.com/s/1ML6hNupaPHPJRd5rcTvQvw?pwd=8ruc) to see how this demo carries out a full 60fps synchronization with the help of _batched input upsync/downsync_ for satisfying network I/O performance.
 

battle_srv/models/pb_type_convert.go

@@ -58,7 +58,7 @@ func toPbRoomDownsyncFrame(rdf *battle.RoomDownsyncFrame) *pb.RoomDownsyncFrame
 			BulletLocalId:           last.BattleAttr.BulletLocalId,
 			OriginatedRenderFrameId: last.BattleAttr.OriginatedRenderFrameId,
 			OffenderJoinIndex:       last.BattleAttr.OffenderJoinIndex,
-			TeamId: last.BattleAttr.TeamId,
+			TeamId:                  last.BattleAttr.TeamId,
 
 			StartupFrames:      last.Bullet.StartupFrames,
 			CancellableStFrame: last.Bullet.CancellableStFrame,
@@ -81,11 +81,11 @@ func toPbRoomDownsyncFrame(rdf *battle.RoomDownsyncFrame) *pb.RoomDownsyncFrame
 
 			BlowUp: last.Bullet.BlowUp,
 
-            SpeciesId: last.Bullet.SpeciesId,
-            ExplosionFrames: last.Bullet.ExplosionFrames,
+			SpeciesId:       last.Bullet.SpeciesId,
+			ExplosionFrames: last.Bullet.ExplosionFrames,
 
-            BlState: last.BlState,
-            FramesInBlState: last.FramesInBlState,
+			BlState:         last.BlState,
+			FramesInBlState: last.FramesInBlState,
 		}
 		ret.MeleeBullets[i] = pbBullet
 	}
@@ -95,7 +95,7 @@ func toPbRoomDownsyncFrame(rdf *battle.RoomDownsyncFrame) *pb.RoomDownsyncFrame
 			BulletLocalId:           last.BattleAttr.BulletLocalId,
 			OriginatedRenderFrameId: last.BattleAttr.OriginatedRenderFrameId,
 			OffenderJoinIndex:       last.BattleAttr.OffenderJoinIndex,
-			TeamId: last.BattleAttr.TeamId,
+			TeamId:                  last.BattleAttr.TeamId,
 
 			StartupFrames:      last.Bullet.StartupFrames,
 			CancellableStFrame: last.Bullet.CancellableStFrame,
@@ -118,11 +118,11 @@ func toPbRoomDownsyncFrame(rdf *battle.RoomDownsyncFrame) *pb.RoomDownsyncFrame
 
 			BlowUp: last.Bullet.BlowUp,
 
-            SpeciesId: last.Bullet.SpeciesId,
-            ExplosionFrames: last.Bullet.ExplosionFrames,
+			SpeciesId:       last.Bullet.SpeciesId,
+			ExplosionFrames: last.Bullet.ExplosionFrames,
 
-            BlState: last.BlState,
-            FramesInBlState: last.FramesInBlState,
+			BlState:         last.BlState,
+			FramesInBlState: last.FramesInBlState,
 
 			VirtualGridX: last.VirtualGridX,
 			VirtualGridY: last.VirtualGridY,

battle_srv/models/room.go

@@ -1342,7 +1342,7 @@ func (pR *Room) doBattleMainLoopPerTickBackendDynamicsWithProperLocking(prevRend
 			snapshotStFrameId = refSnapshotStFrameId
 		}
 		inputsBufferSnapshot := pR.produceInputsBufferSnapshotWithCurDynamicsRenderFrameAsRef(unconfirmedMask, snapshotStFrameId, pR.LastAllConfirmedInputFrameId+1)
-		Logger.Debug(fmt.Sprintf("[forceConfirmation] roomId=%v, room.RenderFrameId=%v, room.CurDynamicsRenderFrameId=%v, room.LastAllConfirmedInputFrameId=%v, unconfirmedMask=%v", pR.Id, pR.RenderFrameId, pR.CurDynamicsRenderFrameId, pR.LastAllConfirmedInputFrameId, unconfirmedMask))
+		//Logger.Warn(fmt.Sprintf("[forceConfirmation] roomId=%v, room.RenderFrameId=%v, room.CurDynamicsRenderFrameId=%v, room.LastAllConfirmedInputFrameId=%v, unconfirmedMask=%v", pR.Id, pR.RenderFrameId, pR.CurDynamicsRenderFrameId, pR.LastAllConfirmedInputFrameId, unconfirmedMask))
 		pR.downsyncToAllPlayers(inputsBufferSnapshot)
 	}
 }
@@ -1457,8 +1457,8 @@ func (pR *Room) downsyncToSinglePlayer(playerId int32, player *Player, refRender
 		pbRefRenderFrame.SpeciesIdList = pR.SpeciesIdList
 		pR.sendSafely(pbRefRenderFrame, toSendInputFrameDownsyncsSnapshot, DOWNSYNC_MSG_ACT_FORCED_RESYNC, playerId, false)
 		//Logger.Warn(fmt.Sprintf("Sent refRenderFrameId=%v & inputFrameIds [%d, %d), for roomId=%v, playerId=%d, playerJoinIndex=%d, renderFrameId=%d, curDynamicsRenderFrameId=%d, playerLastSentInputFrameId=%d: InputsBuffer=%v", refRenderFrameId, toSendInputFrameIdSt, toSendInputFrameIdEd, pR.Id, playerId, player.JoinIndex, pR.RenderFrameId, pR.CurDynamicsRenderFrameId, player.LastSentInputFrameId, pR.InputsBufferString(false)))
-		if shouldResync1 {
-			Logger.Warn(fmt.Sprintf("Sent refRenderFrameId=%v & inputFrameIds [%d, %d), for roomId=%v, playerId=%d, playerJoinIndex=%d, renderFrameId=%d, curDynamicsRenderFrameId=%d, playerLastSentInputFrameId=%d: shouldResync1=%v, shouldResync2=%v, shouldResync3=%v, playerBattleState=%d", refRenderFrameId, toSendInputFrameIdSt, toSendInputFrameIdEd, pR.Id, playerId, player.JoinIndex, pR.RenderFrameId, pR.CurDynamicsRenderFrameId, player.LastSentInputFrameId, shouldResync1, shouldResync2, shouldResync3, playerBattleState))
+		if shouldResync1 || shouldResync3 {
+			Logger.Debug(fmt.Sprintf("Sent refRenderFrameId=%v & inputFrameIds [%d, %d), for roomId=%v, playerId=%d, playerJoinIndex=%d, renderFrameId=%d, curDynamicsRenderFrameId=%d, playerLastSentInputFrameId=%d: shouldResync1=%v, shouldResync2=%v, shouldResync3=%v, playerBattleState=%d", refRenderFrameId, toSendInputFrameIdSt, toSendInputFrameIdEd, pR.Id, playerId, player.JoinIndex, pR.RenderFrameId, pR.CurDynamicsRenderFrameId, player.LastSentInputFrameId, shouldResync1, shouldResync2, shouldResync3, playerBattleState))
 		}
 	} else {
 		pR.sendSafely(nil, toSendInputFrameDownsyncsSnapshot, DOWNSYNC_MSG_ACT_INPUT_BATCH, playerId, false)

frontend/assets/resources/animation/Explosion/Fireball1Explosion.anim

@@ -3,7 +3,7 @@
   "_name": "Fireball1Explosion",
   "_objFlags": 0,
   "_native": "",
-  "_duration": 0.1,
+  "_duration": 0.26666666666666666,
   "sample": 60,
   "speed": 1,
   "wrapMode": 1,
@@ -18,31 +18,31 @@
             }
           },
           {
-            "frame": 0.016666666666666666,
+            "frame": 0.05,
             "value": {
               "__uuid__": "c6a5994f-251d-4191-a550-dfef979bab59"
             }
           },
           {
-            "frame": 0.03333333333333333,
+            "frame": 0.11666666666666667,
             "value": {
               "__uuid__": "417e58d9-e364-47f7-9364-f31ad3452adc"
             }
           },
           {
-            "frame": 0.05,
+            "frame": 0.15,
             "value": {
               "__uuid__": "8b566f26-b34d-4da6-bdaa-078358a5b685"
             }
           },
           {
-            "frame": 0.06666666666666667,
+            "frame": 0.2,
             "value": {
               "__uuid__": "6ec5f75d-307e-4292-b667-cbbb5a52c2f6"
             }
           },
           {
-            "frame": 0.08333333333333333,
+            "frame": 0.25,
             "value": {
               "__uuid__": "d89977f1-d927-4a08-9591-9feb1daf68c8"
             }

frontend/assets/scenes/login.fire

@@ -440,7 +440,7 @@
       "array": [
         0,
         0,
-        217.50722273720794,
+        216.50635094610968,
         0,
         0,
         0,

frontend/assets/scenes/offline_map.fire

@@ -464,7 +464,7 @@
       "array": [
         0,
         0,
-        211.36523796872766,
+        216.50635094610968,
         0,
         0,
         0,

frontend/assets/scripts/Map.js

@@ -134,7 +134,7 @@ cc.Class({
     previousSelfInput = (null == previousInputFrameDownsync ? null : previousInputFrameDownsync.InputList[joinIndex - 1]);
     if (null != existingInputFrame) {
       // This could happen upon either [type#1] or [type#2] forceConfirmation, where "refRenderFrame" is accompanied by some "inputFrameDownsyncs". The check here also guarantees that we don't override history 
-      console.log(`noDelayInputFrameId=${inputFrameId} already exists in recentInputCache: recentInputCache=${self._stringifyRecentInputCache(false)}`);
+      //console.log(`noDelayInputFrameId=${inputFrameId} already exists in recentInputCache: recentInputCache=${self._stringifyRecentInputCache(false)}`);
       return [previousSelfInput, existingInputFrame.InputList[joinIndex - 1]];
     }
 
@@ -152,6 +152,7 @@ cc.Class({
       prefabbedInputList[k] = (prefabbedInputList[k] & 15);
     }
     currSelfInput = self.ctrl.getEncodedInput(); // When "null == existingInputFrame", it'd be safe to say that the realtime "self.ctrl.getEncodedInput()" is for the requested "inputFrameId"
+    //console.log(`@rdf.Id=${self.renderFrameId}, currSelfInput=${currSelfInput}`);
     prefabbedInputList[(joinIndex - 1)] = currSelfInput;
     while (self.recentInputCache.EdFrameId <= inputFrameId) {
       // Fill the gap
@@ -916,9 +917,9 @@ batchInputFrameIdRange=[${batch[0].inputFrameId}, ${batch[batch.length - 1].inpu
       }
       try {
         let st = performance.now();
+        const noDelayInputFrameId = gopkgs.ConvertToNoDelayInputFrameId(self.renderFrameId);
         let prevSelfInput = null,
           currSelfInput = null;
-        const noDelayInputFrameId = gopkgs.ConvertToNoDelayInputFrameId(self.renderFrameId);
         if (gopkgs.ShouldGenerateInputFrameUpsync(self.renderFrameId)) {
           [prevSelfInput, currSelfInput] = self.getOrPrefabInputFrameUpsync(noDelayInputFrameId);
         }
@@ -1195,13 +1196,8 @@ othersForcedDownsyncRenderFrame=${JSON.stringify(othersForcedDownsyncRenderFrame
         throw `Couldn't find renderFrame for i=${i} to rollback (are you using Firefox?), self.renderFrameId=${self.renderFrameId}, lastAllConfirmedInputFrameId=${self.lastAllConfirmedInputFrameId}, might've been interruptted by onRoomDownsyncFrame`;
       }
       const j = gopkgs.ConvertToDelayedInputFrameId(i);
-      const delayedInputFrame = self.recentInputCache.GetByFrameId(j); // Don't make prediction here, the inputFrameDownsyncs in recentInputCache was already predicted while prefabbing
-      if (null == delayedInputFrame) {
-        // Shouldn't happen!
-        throw `Failed to get cached delayedInputFrame for i=${i}, j=${j}, renderFrameId=${self.renderFrameId}, lastUpsyncInputFrameId=${self.lastUpsyncInputFrameId}, lastAllConfirmedInputFrameId=${self.lastAllConfirmedInputFrameId}, chaserRenderFrameId=${self.chaserRenderFrameId}; recentRenderCache=${self._stringifyRecentRenderCache(false)}, recentInputCache=${self._stringifyRecentInputCache(false)}`;
-      }
+      const delayedInputFrame = self.getOrPrefabInputFrameUpsync(j);
 
-      const jPrev = gopkgs.ConvertToDelayedInputFrameId(i - 1);
       if (self.frameDataLoggingEnabled) {
         const actuallyUsedInputClone = delayedInputFrame.InputList.slice();
         const inputFrameDownsyncClone = {

frontend/assets/scripts/OfflineMap.js

@@ -94,7 +94,7 @@ cc.Class({
       const p2Vpos = gopkgs.WorldToVirtualGridPos(boundaryObjs.playerStartingPositions[1].x, boundaryObjs.playerStartingPositions[1].y);
       const colliderRadiusV = gopkgs.WorldToVirtualGridPos(12.0, 0);
 
-      const speciesIdList = [1, 4096];
+      const speciesIdList = [4096, 1];
       const chConfigsOrderedByJoinIndex = gopkgs.GetCharacterConfigsOrderedByJoinIndex(speciesIdList);
 
       const startRdf = window.pb.protos.RoomDownsyncFrame.create({

frontend/assets/scripts/TouchEventsManager.js

@@ -106,8 +106,13 @@ cc.Class({
     this.cachedBtnDownLevel = 0;
     this.cachedBtnLeftLevel = 0;
     this.cachedBtnRightLevel = 0;
+
+    this.realtimeBtnALevel = 0;
     this.cachedBtnALevel = 0;
+    this.btnAEdgeTriggerLock = false;
+    this.realtimeBtnBLevel = 0;
     this.cachedBtnBLevel = 0;
+    this.btnBEdgeTriggerLock = false;
 
     this.canvasNode = this.mapNode.parent;
     this.mainCameraNode = this.canvasNode.getChildByName("Main Camera"); // Cannot drag and assign the `mainCameraNode` from CocosCreator EDITOR directly, otherwise it'll cause an infinite loading time, till v2.1.0.
@@ -163,30 +168,30 @@ cc.Class({
 
     if (self.btnA) {
       self.btnA.on(cc.Node.EventType.TOUCH_START, function(evt) {
-        self.cachedBtnALevel = 1;
+        self._triggerEdgeBtnA(true);
         evt.target.runAction(cc.scaleTo(0.1, 0.3));
       });
       self.btnA.on(cc.Node.EventType.TOUCH_END, function(evt) {
-        self.cachedBtnALevel = 0;
+        self._triggerEdgeBtnA(false);
         evt.target.runAction(cc.scaleTo(0.1, 1.0));
       });
       self.btnA.on(cc.Node.EventType.TOUCH_CANCEL, function(evt) {
-        self.cachedBtnALevel = 0;
+        self._triggerEdgeBtnA(false);
         evt.target.runAction(cc.scaleTo(0.1, 1.0));
       });
     }
 
     if (self.btnB) {
       self.btnB.on(cc.Node.EventType.TOUCH_START, function(evt) {
-        self.cachedBtnBLevel = 1;
+        self._triggerEdgeBtnB(true);
         evt.target.runAction(cc.scaleTo(0.1, 0.3));
       });
       self.btnB.on(cc.Node.EventType.TOUCH_END, function(evt) {
-        self.cachedBtnBLevel = 0;
+        self._triggerEdgeBtnB(false);
         evt.target.runAction(cc.scaleTo(0.1, 1.0));
       });
       self.btnB.on(cc.Node.EventType.TOUCH_CANCEL, function(evt) {
-        self.cachedBtnBLevel = 0;
+        self._triggerEdgeBtnB(false);
         evt.target.runAction(cc.scaleTo(0.1, 1.0));
       });
     }
@@ -223,10 +228,10 @@ cc.Class({
           self.cachedBtnRightLevel = 1;
           break;
         case cc.macro.KEY.h:
-          self.cachedBtnALevel = 1;
+          self._triggerEdgeBtnA(true);
           break;
         case cc.macro.KEY.j:
-          self.cachedBtnBLevel = 1;
+          self._triggerEdgeBtnB(true);
           break;
         default:
           break;
@@ -248,10 +253,10 @@ cc.Class({
           self.cachedBtnRightLevel = 0;
           break;
         case cc.macro.KEY.h:
-          self.cachedBtnALevel = 0;
+          self._triggerEdgeBtnA(false);
           break;
         case cc.macro.KEY.j:
-          self.cachedBtnBLevel = 0;
+          self._triggerEdgeBtnB(false);
           break;
         default:
           break;
@@ -464,6 +469,12 @@ cc.Class({
     const discretizedDir = this.discretizeDirection(this.stickhead.x, this.stickhead.y, this.joyStickEps).encodedIdx; // There're only 9 dirs, thus using only the lower 4-bits
     const btnALevel = (this.cachedBtnALevel << 4);
     const btnBLevel = (this.cachedBtnBLevel << 5);
+
+    this.cachedBtnALevel = this.realtimeBtnALevel;
+    this.cachedBtnBLevel = this.realtimeBtnBLevel;
+
+    this.btnAEdgeTriggerLock = false;
+    this.btnBEdgeTriggerLock = false;
     return (btnBLevel + btnALevel + discretizedDir);
   },
 
@@ -482,4 +493,20 @@ cc.Class({
       btnBLevel: btnBLevel,
     });
   },
+
+  _triggerEdgeBtnA(rising) {
+    this.realtimeBtnALevel = (rising ? 1 : 0);
+    if (!this.btnAEdgeTriggerLock && (1 - this.realtimeBtnALevel) == this.cachedBtnALevel) {
+      this.cachedBtnALevel = this.realtimeBtnALevel;
+      this.btnAEdgeTriggerLock = true;
+    }
+  },
+
+  _triggerEdgeBtnB(rising) {
+    this.realtimeBtnBLevel = (rising ? 1 : 0);
+    if (!this.btnBEdgeTriggerLock && (1 - this.realtimeBtnBLevel) == this.cachedBtnBLevel) {
+      this.cachedBtnBLevel = this.realtimeBtnBLevel;
+      this.btnBEdgeTriggerLock = true;
+    }
+  },
 });

frontend/settings/project.json

@@ -68,7 +68,7 @@
     "shelter_z_reducer",
     "shelter"
   ],
-  "last-module-event-record-time": 1673325961305,
+  "last-module-event-record-time": 1673930863015,
   "simulator-orientation": false,
   "simulator-resolution": {
     "height": 640,

jsexport/battle/battle.go

@@ -23,7 +23,7 @@ const (
 	GRAVITY_Y = -int32(float64(0.5) * WORLD_TO_VIRTUAL_GRID_RATIO) // makes all "playerCollider.Y" a multiple of 0.5 in all cases
 
 	INPUT_DELAY_FRAMES = int32(4)  // in the count of render frames
-	INPUT_SCALE_FRAMES = uint32(2) // inputDelayedAndScaledFrameId = ((originalFrameId - InputDelayFrames) >> InputScaleFrames)
+	INPUT_SCALE_FRAMES = uint32(3) // inputDelayedAndScaledFrameId = ((originalFrameId - InputDelayFrames) >> InputScaleFrames)
 	NST_DELAY_FRAMES   = int32(16) // network-single-trip delay in the count of render frames, proposed to be (InputDelayFrames >> 1) because we expect a round-trip delay to be exactly "InputDelayFrames"
 
 	SP_ATK_LOOKUP_FRAMES = int32(5)

jsexport/battle/characterConfig.go

@@ -302,7 +302,7 @@ var skills = map[int]*Skill{
 					HitboxOffsetY:      int32(0),
 					HitboxSizeX:        int32(float64(24) * WORLD_TO_VIRTUAL_GRID_RATIO),
 					HitboxSizeY:        int32(float64(32) * WORLD_TO_VIRTUAL_GRID_RATIO),
-					CancellableStFrame: int32(13),
+					CancellableStFrame: int32(8),
 					CancellableEdFrame: int32(30),
 
 					CancelTransit: map[int]int{
@@ -337,7 +337,7 @@ var skills = map[int]*Skill{
 					HitboxOffsetY:      int32(0),
 					HitboxSizeX:        int32(float64(24) * WORLD_TO_VIRTUAL_GRID_RATIO),
 					HitboxSizeY:        int32(float64(32) * WORLD_TO_VIRTUAL_GRID_RATIO),
-					CancellableStFrame: int32(22),
+					CancellableStFrame: int32(19),
 					CancellableEdFrame: int32(36),
 					CancelTransit: map[int]int{
 						1: 6,
@@ -500,7 +500,7 @@ var skills = map[int]*Skill{
 					HitboxSizeX:     int32(float64(48) * WORLD_TO_VIRTUAL_GRID_RATIO),
 					HitboxSizeY:     int32(float64(32) * WORLD_TO_VIRTUAL_GRID_RATIO),
 					BlowUp:          false,
-					ExplosionFrames: 5,
+					ExplosionFrames: 15,
 					SpeciesId:       int32(1),
 				},
 			},