Updated documentation.

README.md

@@ -10,6 +10,11 @@ This project is a demo for a websocket-based rollback netcode inspired by [GGPO]
 
 ![Phone4g_battle_spedup](./charts/Phone4g_battle_spedup.gif)
 
+**Since v1.0.12, smoothness in worst cases (e.g. turn-around on ground, in air and after dashing) is drastically improved due to update of prediction approach. The gifs and corresponding screenrecordings above are not updated because there's no big difference when network is good -- however, `input delay` is now set to `4 frames` -- while `input delay = 6 frames` was used in the screenrecordings -- and smoothness is even better now.** Key changes are listed below.
+- [change#1](https://github.com/genxium/DelayNoMore/blob/de9f3c90902bc6da98359be996887a55964e011e/jsexport/battle/battle.go#L647)
+- [change#2](https://github.com/genxium/DelayNoMore/blob/de9f3c90902bc6da98359be996887a55964e011e/frontend/assets/scripts/Map.js#L1451)
+- [change#3](https://github.com/genxium/DelayNoMore/blob/de9f3c90902bc6da98359be996887a55964e011e/battle_srv/models/room.go#L1312)
+
 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) -- **since v0.9.25, the project is actually equipped with UDP capabilities as follows**.
 - When using the so called `native apps` on `Android` and `Windows` (I'm working casually hard to support `iOS` next), the frontends will try to use UDP hole-punching w/ the help of backend as a registry. If UDP hole-punching is working, the rollback is often less than `turn-around frames to recover` and thus not noticeable, being much better than using websocket alone. This video shows how the UDP holepunched p2p performs for [Phone-Wifi v.s. PC-Wifi (viewed by PC side)](https://pan.baidu.com/s/1K6704bJKlrSBTVqGcXhajA?pwd=l7ok).
 - If UDP hole-punching is not working, e.g. for Symmetric NAT like in 4G/5G cellular network, the frontends will use backend as a UDP tunnel (or relay, whatever you like to call it). This video shows how the UDP tunnel performs for [Phone-4G v.s. PC-Wifi (merged view@v0.9.34, excellent synchronization)](https://pan.baidu.com/s/1yeIrN5TSf6_av_8-N3vdVg?pwd=7tzw). 

battle_srv/models/room.go

@@ -808,7 +808,7 @@ func (pR *Room) OnDismissed() {
 	pR.RenderFrameBuffer = resolv.NewRingBuffer(pR.RenderCacheSize)
 	pR.InputsBuffer = resolv.NewRingBuffer((pR.RenderCacheSize >> 1) + 1)
 	pR.rdfIdToActuallyUsedInput = make(map[int32]*pb.InputFrameDownsync)
-	pR.allowUpdateInputFrameInPlaceUponDynamics = false
+	pR.allowUpdateInputFrameInPlaceUponDynamics = true
 	pR.LastIndividuallyConfirmedInputFrameId = make([]int32, pR.Capacity)
 	for i := 0; i < pR.Capacity; i++ {
 		pR.LastIndividuallyConfirmedInputFrameId[i] = MAGIC_LAST_SENT_INPUT_FRAME_ID_NORMAL_ADDED
@@ -1201,7 +1201,8 @@ func (pR *Room) markConfirmationIfApplicable(inputFrameUpsyncBatch []*pb.InputFr
 		}
 		if clientInputFrameId < player.LastConsecutiveRecvInputFrameId {
 			// [WARNING] It's important for correctness that we use "player.LastConsecutiveRecvInputFrameId" instead of "pR.LastIndividuallyConfirmedInputFrameId[player.JoinIndex-1]" here!
-			Logger.Debug(fmt.Sprintf("Omitting obsolete inputFrameUpsync#2: roomId=%v, playerId=%v, clientInputFrameId=%v, playerLastConsecutiveRecvInputFrameId=%v, InputsBuffer=%v", pR.Id, playerId, clientInputFrameId, player.LastConsecutiveRecvInputFrameId, pR.InputsBufferString(false)))
+			//Logger.Debug(fmt.Sprintf("Omitting obsolete inputFrameUpsync#2: roomId=%v, playerId=%v, clientInputFrameId=%v, playerLastConsecutiveRecvInputFrameId=%v, InputsBuffer=%v", pR.Id, playerId, clientInputFrameId, player.LastConsecutiveRecvInputFrameId, pR.InputsBufferString(false)))
+			Logger.Debug(fmt.Sprintf("Omitting obsolete inputFrameUpsync#2: roomId=%v, playerId=%v, clientInputFrameId=%v, playerLastConsecutiveRecvInputFrameId=%v", pR.Id, playerId, clientInputFrameId, player.LastConsecutiveRecvInputFrameId))
 			continue
 		}
 		if clientInputFrameId > pR.InputsBuffer.EdFrameId {
@@ -1259,7 +1260,7 @@ func (pR *Room) markConfirmationIfApplicable(inputFrameUpsyncBatch []*pb.InputFr
 					shouldBreakConfirmation = true // Could be an `ACTIVE SLOW TICKER` here, but no action needed for now
 					break
 				}
-				Logger.Debug(fmt.Sprintf("markConfirmationIfApplicable for roomId=%v, skipping UNCONFIRMED BUT INACTIVE player(id:%v, joinIndex:%v) while checking inputFrameId=[%v, %v): InputsBuffer=%v", pR.Id, player.Id, player.JoinIndex, inputFrameId1, pR.InputsBuffer.EdFrameId, pR.InputsBufferString(false)))
+				//Logger.Debug(fmt.Sprintf("markConfirmationIfApplicable for roomId=%v, skipping UNCONFIRMED BUT INACTIVE player(id:%v, joinIndex:%v) while checking inputFrameId=[%v, %v): InputsBuffer=%v", pR.Id, player.Id, player.JoinIndex, inputFrameId1, pR.InputsBuffer.EdFrameId, pR.InputsBufferString(false)))
 			}
 		}
 
@@ -1308,12 +1309,9 @@ func (pR *Room) forceConfirmationIfApplicable(prevRenderFrameId int32) uint64 {
 				panic(fmt.Sprintf("inputFrameId=%v doesn't exist for roomId=%v! InputsBuffer=%v", j, pR.Id, pR.InputsBufferString(false)))
 			}
 			inputFrameDownsync := tmp.(*battle.InputFrameDownsync)
-			/*
-			            // [WARN] Frame logging showed that using "battle.UpdateInputFrameInPlaceUponDynamics" here would CONTAMINATE "all-confirmed inputs already sent & recognized by the frontends", root cause remains to be invesitgated!
-						if pR.allowUpdateInputFrameInPlaceUponDynamics {
-							battle.UpdateInputFrameInPlaceUponDynamics(j, pR.Capacity, inputFrameDownsync.ConfirmedList, inputFrameDownsync.InputList, pR.LastIndividuallyConfirmedInputFrameId, pR.LastIndividuallyConfirmedInputList, int32(MAGIC_JOIN_INDEX_INVALID))
-						}
-			*/
+			if pR.allowUpdateInputFrameInPlaceUponDynamics {
+				battle.UpdateInputFrameInPlaceUponDynamics(j, pR.Capacity, inputFrameDownsync.ConfirmedList, inputFrameDownsync.InputList, pR.LastIndividuallyConfirmedInputFrameId, pR.LastIndividuallyConfirmedInputList, int32(MAGIC_JOIN_INDEX_INVALID))
+			}
 			unconfirmedMask |= (allConfirmedMask ^ inputFrameDownsync.ConfirmedList)
 			inputFrameDownsync.ConfirmedList = allConfirmedMask
 			pR.onInputFrameDownsyncAllConfirmed(inputFrameDownsync, -1)
@@ -1394,7 +1392,7 @@ func (pR *Room) applyInputFrameDownsyncDynamics(fromRenderFrameId int32, toRende
 			}
 		}
 
-		battle.ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame(pR.InputsBuffer, currRenderFrame.Id, pR.Space, pR.CollisionSysMap, pR.SpaceOffsetX, pR.SpaceOffsetY, pR.CharacterConfigsArr, pR.RenderFrameBuffer, pR.collisionHolder, pR.effPushbacks, pR.hardPushbackNormsArr, pR.jumpedOrNotList, pR.dynamicRectangleColliders, pR.LastIndividuallyConfirmedInputFrameId, pR.LastIndividuallyConfirmedInputList, false, MAGIC_JOIN_INDEX_INVALID) // "allowUpdateInputFrameInPlaceUponDynamics" is instead used when "forceConfirmationIfApplicable"
+		battle.ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame(pR.InputsBuffer, currRenderFrame.Id, pR.Space, pR.CollisionSysMap, pR.SpaceOffsetX, pR.SpaceOffsetY, pR.CharacterConfigsArr, pR.RenderFrameBuffer, pR.collisionHolder, pR.effPushbacks, pR.hardPushbackNormsArr, pR.jumpedOrNotList, pR.dynamicRectangleColliders, pR.LastIndividuallyConfirmedInputFrameId, pR.LastIndividuallyConfirmedInputList, false, MAGIC_JOIN_INDEX_INVALID) // "allowUpdateInputFrameInPlaceUponDynamics" is instead used in "forceConfirmationIfApplicable"
 		pR.CurDynamicsRenderFrameId++
 	}
 }
@@ -1545,6 +1543,7 @@ func (pR *Room) downsyncToAllPlayers(inputsBufferSnapshot *pb.InputsBufferSnapsh
 				break
 			}
 		}
+
 	}
 
 	for _, player := range pR.PlayersArr {
@@ -1561,11 +1560,16 @@ func (pR *Room) downsyncToAllPlayers(inputsBufferSnapshot *pb.InputsBufferSnapsh
 
 		if playerDownsyncChan, existent := pR.PlayerDownsyncChanDict[player.Id]; existent {
 			playerDownsyncChan <- (*inputsBufferSnapshot)
-			//Logger.Info(fmt.Sprintf("Sent inputsBufferSnapshot(refRenderFrameId:%d, unconfirmedMask:%v) to for (roomId: %d, playerId:%d, playerDownsyncChan:%p)#1", inputsBufferSnapshot.RefRenderFrameId, inputsBufferSnapshot.UnconfirmedMask, pR.Id, player.Id, playerDownsyncChan))
+			//Logger.Info(fmt.Sprintf("Sent inputsBufferSnapshot{refRenderFrameId:%d, unconfirmedMask:%v} to {roomId: %d, playerId:%d, playerDownsyncChan:%p}#1", inputsBufferSnapshot.RefRenderFrameId, inputsBufferSnapshot.UnconfirmedMask, pR.Id, player.Id, playerDownsyncChan))
 		} else {
 			Logger.Warn(fmt.Sprintf("playerDownsyncChan for (roomId: %d, playerId:%d) is gone", pR.Id, player.Id))
 		}
 	}
+	/*
+		toSendInputFrameDownsyncs := inputsBufferSnapshot.ToSendInputFrameDownsyncs
+		toSendInputFrameIdSt, toSendInputFrameIdEd := toSendInputFrameDownsyncs[0].InputFrameId, toSendInputFrameDownsyncs[len(toSendInputFrameDownsyncs)-1].InputFrameId+1
+		Logger.Info(fmt.Sprintf("Sent inputsBufferSnapshot{refRenderFrameId:%d, unconfirmedMask:%v, inputFrameIdRange:[%d, %d)} to {roomId: %d}", inputsBufferSnapshot.RefRenderFrameId, inputsBufferSnapshot.UnconfirmedMask, toSendInputFrameIdSt, toSendInputFrameIdEd, pR.Id))
+	*/
 }
 
 func (pR *Room) downsyncToSinglePlayer(playerId int32, player *Player, refRenderFrameId int32, unconfirmedMask uint64, toSendInputFrameDownsyncsSnapshot []*pb.InputFrameDownsync, shouldForceResync bool) {
@@ -1609,9 +1613,9 @@ func (pR *Room) downsyncToSinglePlayer(playerId int32, player *Player, refRender
 		pbRefRenderFrame.SpeciesIdList = pR.SpeciesIdList
 		pR.sendSafely(pbRefRenderFrame, toSendInputFrameDownsyncsSnapshot, DOWNSYNC_MSG_ACT_FORCED_RESYNC, playerId, false, MAGIC_JOIN_INDEX_DEFAULT)
 		if shouldResync1 || shouldResync3 {
-			Logger.Info(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))
+			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 {
-			Logger.Debug(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)))
+			//Logger.Debug(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)))
 		}
 	} else {
 		pR.sendSafely(nil, toSendInputFrameDownsyncsSnapshot, DOWNSYNC_MSG_ACT_INPUT_BATCH, playerId, false, MAGIC_JOIN_INDEX_DEFAULT)

frontend/assets/scenes/offline_map.fire

@@ -518,7 +518,7 @@
       "array": [
         0,
         0,
-        217.5376534000385,
+        210.43877906529718,
         0,
         0,
         0,

frontend/assets/scripts/Map.js

@@ -968,7 +968,7 @@ accompaniedInputFrameDownsyncBatchRange=[${accompaniedInputFrameDownsyncBatch[0]
 firstPredictedYetIncorrectInputFrameId: ${firstPredictedYetIncorrectInputFrameId}
 lastAllConfirmedInputFrameId=${self.lastAllConfirmedInputFrameId}
 recentInputCache=${self._stringifyRecentInputCache(false)}
-batchInputFrameIdRange=[${batch[0].inputFrameId}, ${batch[batch.length - 1].inputFrameId}]
+batchInputFrameIdRange=[${null == batch ? null : batch[0].inputFrameId}, ${null == batch ? null : batch[batch.length - 1].inputFrameId}]
 fromUDP=${fromUDP}`);
     }
     self.chaserRenderFrameId = renderFrameId1;
@@ -1439,7 +1439,21 @@ othersForcedDownsyncRenderFrame=${self._stringifyGopkgRdfForFrameDataLogging(oth
       const delayedInputFrame = gopkgs.GetInputFrameDownsync(self.recentInputCache, j);
 
       const allowUpdateInputFrameInPlaceUponDynamics = (!isChasing);
-      const renderRes = gopkgs.ApplyInputFrameDownsyncDynamicsOnSingleRenderFrameJs(self.recentInputCache, i, collisionSys, collisionSysMap, self.spaceOffsetX, self.spaceOffsetY, self.chConfigsOrderedByJoinIndex, self.recentRenderCache, self.collisionHolder, self.effPushbacks, self.hardPushbackNormsArr, self.jumpedOrNotList, self.dynamicRectangleColliders, self.lastIndividuallyConfirmedInputFrameId, self.lastIndividuallyConfirmedInputList, allowUpdateInputFrameInPlaceUponDynamics, self.selfPlayerInfo.joinIndex);
+      const hasInputFrameUpdatedOnDynamics = gopkgs.ApplyInputFrameDownsyncDynamicsOnSingleRenderFrameJs(self.recentInputCache, i, collisionSys, collisionSysMap, self.spaceOffsetX, self.spaceOffsetY, self.chConfigsOrderedByJoinIndex, self.recentRenderCache, self.collisionHolder, self.effPushbacks, self.hardPushbackNormsArr, self.jumpedOrNotList, self.dynamicRectangleColliders, self.lastIndividuallyConfirmedInputFrameId, self.lastIndividuallyConfirmedInputList, allowUpdateInputFrameInPlaceUponDynamics, self.selfPlayerInfo.joinIndex);
+      if (hasInputFrameUpdatedOnDynamics) {
+        const ii = gopkgs.ConvertToFirstUsedRenderFrameId(j);
+        if (ii < i) {
+          /*
+          [WARNING] 
+          If we don't rollback at this spot, when the mutated "delayedInputFrame.inputList" a.k.a. "inputFrame#j" matches the later downsynced version, rollback WOULDN'T be triggered for the incorrectly rendered "renderFrame#(ii+1)", and it would STAY IN HISTORY FOREVER -- as the history becomes incorrect, EVERY LATEST renderFrame since "inputFrame#j" was mutated would be ALWAYS incorrectly rendering too!
+
+          The backend counterpart doesn't need this rollback because 
+          1. Backend only applies all-confirmed inputFrames to calc dynamics.
+          2. Backend applies an all-confirmed inputFrame to all applicable render frames at once.
+          */
+          self._handleIncorrectlyRenderedPrediction(j, null, false);
+        }
+      }
       if (self.frameDataLoggingEnabled) {
         // [WARNING] The "inputList" of "delayedInputFrame" could be mutated in "ApplyInputFrameDownsyncDynamicsOnSingleRenderFrameJs", thus should clone after dynamics is applied!  
         const actuallyUsedInputClone = delayedInputFrame.GetInputList().slice();

jsexport/battle/battle.go

@@ -490,7 +490,8 @@ func calcHardPushbacksNorms(joinIndex int32, currPlayerDownsync, thatPlayerInNex
 	return retCnt
 }
 
-func UpdateInputFrameInPlaceUponDynamics(inputFrameId int32, roomCapacity int, confirmedList uint64, inputList []uint64, lastIndividuallyConfirmedInputFrameId []int32, lastIndividuallyConfirmedInputList []uint64, toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics int32) {
+func UpdateInputFrameInPlaceUponDynamics(inputFrameId int32, roomCapacity int, confirmedList uint64, inputList []uint64, lastIndividuallyConfirmedInputFrameId []int32, lastIndividuallyConfirmedInputList []uint64, toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics int32) bool {
+	hasInputFrameUpdatedOnDynamics := false
 	for i := 0; i < roomCapacity; i++ {
 		if int32(i+1) == toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics {
 			// On frontend, a "self input" is only confirmed by websocket downsync, which is quite late and might get the "self input" incorrectly overwritten if not excluded here
@@ -503,8 +504,13 @@ func UpdateInputFrameInPlaceUponDynamics(inputFrameId int32, roomCapacity int, c
 		if lastIndividuallyConfirmedInputFrameId[i] >= inputFrameId {
 			continue
 		}
-		inputList[i] = (lastIndividuallyConfirmedInputList[i] & uint64(15))
+		newVal := (lastIndividuallyConfirmedInputList[i] & uint64(15))
+		if newVal != inputList[i] {
+			inputList[i] = newVal
+			hasInputFrameUpdatedOnDynamics = true
+		}
 	}
+	return hasInputFrameUpdatedOnDynamics
 }
 
 func deriveOpPattern(currPlayerDownsync, thatPlayerInNextFrame *PlayerDownsync, currRenderFrame *RoomDownsyncFrame, chConfig *CharacterConfig, inputsBuffer *resolv.RingBuffer) (int, bool, int32, int32) {
@@ -585,6 +591,7 @@ func deriveOpPattern(currPlayerDownsync, thatPlayerInNextFrame *PlayerDownsync,
 The function "ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame" is creating new heap-memory blocks at 60fps, e.g. nextRenderFramePlayers & nextRenderFrameMeleeBullets & nextRenderFrameFireballBullets & effPushbacks & hardPushbackNorms & jumpedOrNotList & dynamicRectangleColliders("player" & "bullet"), which would induce "possibly performance impacting garbage collections" when many rooms are running simultaneously.
 */
 func ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame(inputsBuffer *resolv.RingBuffer, currRenderFrameId int32, collisionSys *resolv.Space, collisionSysMap map[int32]*resolv.Object, collisionSpaceOffsetX, collisionSpaceOffsetY float64, chConfigsOrderedByJoinIndex []*CharacterConfig, renderFrameBuffer *resolv.RingBuffer, collision *resolv.Collision, effPushbacks []*Vec2D, hardPushbackNormsArr [][]*Vec2D, jumpedOrNotList []bool, dynamicRectangleColliders []*resolv.Object, lastIndividuallyConfirmedInputFrameId []int32, lastIndividuallyConfirmedInputList []uint64, allowUpdateInputFrameInPlaceUponDynamics bool, toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics int32) bool {
+	hasInputFrameUpdatedOnDynamics := false
 	currRenderFrame := renderFrameBuffer.GetByFrameId(currRenderFrameId).(*RoomDownsyncFrame)
 	nextRenderFrameId := currRenderFrameId + 1
 	roomCapacity := len(currRenderFrame.PlayersArr)
@@ -637,7 +644,7 @@ func ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame(inputsBuffer *resolv.Rin
 		delayedInputList := delayedInputFrameDownsync.InputList
 		roomCapacity := len(delayedInputList)
 		if allowUpdateInputFrameInPlaceUponDynamics {
-			UpdateInputFrameInPlaceUponDynamics(delayedInputFrameId, roomCapacity, delayedInputFrameDownsync.ConfirmedList, delayedInputList, lastIndividuallyConfirmedInputFrameId, lastIndividuallyConfirmedInputList, toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics)
+			hasInputFrameUpdatedOnDynamics = UpdateInputFrameInPlaceUponDynamics(delayedInputFrameId, roomCapacity, delayedInputFrameDownsync.ConfirmedList, delayedInputList, lastIndividuallyConfirmedInputFrameId, lastIndividuallyConfirmedInputList, toExcludeJoinIndexUpdateInputFrameInPlaceUponDynamics)
 		}
 	}
 
@@ -1210,7 +1217,7 @@ func ApplyInputFrameDownsyncDynamicsOnSingleRenderFrame(inputsBuffer *resolv.Rin
 	ret.Id = nextRenderFrameId
 	ret.BulletLocalIdCounter = bulletLocalId
 
-	return true
+	return hasInputFrameUpdatedOnDynamics
 }
 
 func GenerateRectCollider(wx, wy, w, h, topPadding, bottomPadding, leftPadding, rightPadding, spaceOffsetX, spaceOffsetY float64, data interface{}, tag string) *resolv.Object {