Minor fix for "false == Room.BackendDynamicsEnabled".

README.md

@@ -3,9 +3,12 @@
 This project is a demo for a websocket-based input synchronization method inspired by [GGPO](https://www.ggpo.net/).   
 ![screenshot-1](./screenshot-1.png)
 
-Please checkout [this demo video](https://pan.baidu.com/s/1aM6e8IWaJszFCYAsRjt19g?pwd=z02c) to see whether the source codes are doing what you expect for synchronization.
+Please checkout [this demo video](https://pan.baidu.com/s/123LlWcT9X-wbcYybqYnvmA?pwd=qrlw) to see whether the source codes are doing what you expect for synchronization.
 
-The video mainly shows the following feature (yet I'm not surprised if they're not obvious): when a player didn't have its input arrived at the backend in time (e.g. due to local lag, network delay or reconnection), backend forces confirmation of a prediction of its own and sends the confirmed input together w/ a reference render frame to that player.
+The video mainly shows the following features.
+- The backend receives inputs from frontend peers and [by a GGPO-alike manner](https://github.com/pond3r/ggpo/blob/master/doc/README.md) broadcasts back for synchronization.
+- The game is recovered for a player upon reconnection.
+- Both backend(Golang) and frontend(JavaScript) execute collision detection and handle collision contacts by the same algorithm. The backend dynamics can be toggled off by [Room.BackendDynamicsEnabled](https://github.com/genxium/DelayNoMore/blob/v0.5.2/battle_srv/models/room.go#L813), but **when turned off the game couldn't support recovery upon reconnection**.
 
 # 1. Building & running
 

battle_srv/models/room.go

@@ -2,12 +2,17 @@ package models
 
 import (
 	. "dnmshared"
+	"encoding/xml"
 	"fmt"
 	"github.com/golang/protobuf/proto"
 	"github.com/gorilla/websocket"
 	"github.com/solarlune/resolv"
 	"go.uber.org/zap"
+	"io/ioutil"
+	"math"
 	"math/rand"
+	"os"
+	"path/filepath"
 	. "server/common"
 	"server/common/utils"
 	pb "server/pb_output"
@@ -15,11 +20,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
-
-	"encoding/xml"
-	"io/ioutil"
-	"os"
-	"path/filepath"
 )
 
 const (
@@ -459,9 +459,9 @@ func (pR *Room) StartBattle() {
 				pR.prefabInputFrameDownsync(noDelayInputFrameId)
 			}
 
-			// Force setting all-confirmed of buffered inputFrames periodically
 			unconfirmedMask := uint64(0)
 			if pR.BackendDynamicsEnabled {
+				// Force setting all-confirmed of buffered inputFrames periodically
 				unconfirmedMask = pR.forceConfirmationIfApplicable()
 			} else {
 				pR.markConfirmationIfApplicable()
@@ -474,7 +474,7 @@ func (pR *Room) StartBattle() {
 
 			   If "NstDelayFrames" becomes larger, "pR.RenderFrameId - refRenderFrameId" possibly becomes larger because the force confirmation is delayed more.
 
-			   Hence even upon resync, it's still possible that "refRenderFrameId < frontend.chaserRenderFrameId".
+			   Upon resync, it's still possible that "refRenderFrameId < frontend.chaserRenderFrameId" -- and this is allowed.
 			*/
 			refRenderFrameId := pR.ConvertToGeneratingRenderFrameId(upperToSendInputFrameId) + (1 << pR.InputScaleFrames) - 1
 			if refRenderFrameId > pR.RenderFrameId {
@@ -539,7 +539,7 @@ func (pR *Room) StartBattle() {
 						// [WARNING] When sending DOWNSYNC_MSG_ACT_FORCED_RESYNC, there MUST BE accompanying "toSendInputFrames" for calculating "refRenderFrameId"!
 
 						if MAGIC_LAST_SENT_INPUT_FRAME_ID_READDED == player.LastSentInputFrameId {
-							Logger.Warn(fmt.Sprintf("Not sending due to empty toSendInputFrames: roomId=%v, playerId=%v, refRenderFrameId=%v, candidateToSendInputFrameId=%v, upperToSendInputFrameId=%v, lastSentInputFrameId=%v, playerAckingInputFrameId=%v", pR.Id, playerId, refRenderFrameId, candidateToSendInputFrameId, upperToSendInputFrameId, player.LastSentInputFrameId, player.AckingInputFrameId))
+							Logger.Warn(fmt.Sprintf("Not sending due to empty toSendInputFrames: roomId=%v, playerId=%v, refRenderFrameId=%v, upperToSendInputFrameId=%v, lastSentInputFrameId=%v, playerAckingInputFrameId=%v", pR.Id, playerId, refRenderFrameId, upperToSendInputFrameId, player.LastSentInputFrameId, player.AckingInputFrameId))
 						}
 						continue
 					}
@@ -567,6 +567,17 @@ func (pR *Room) StartBattle() {
 			}
 
 			toApplyInputFrameId := pR.ConvertToInputFrameId(refRenderFrameId, pR.InputDelayFrames)
+			if false == pR.BackendDynamicsEnabled {
+				// When "false == pR.BackendDynamicsEnabled", the variable "refRenderFrameId" is not well defined
+				minLastSentInputFrameId := int32(math.MaxInt32)
+				for _, player := range pR.Players {
+					if player.LastSentInputFrameId >= minLastSentInputFrameId {
+						continue
+					}
+					minLastSentInputFrameId = player.LastSentInputFrameId
+				}
+				toApplyInputFrameId = minLastSentInputFrameId
+			}
 			for pR.InputsBuffer.N < pR.InputsBuffer.Cnt || (0 < pR.InputsBuffer.Cnt && pR.InputsBuffer.StFrameId < toApplyInputFrameId) {
 				f := pR.InputsBuffer.Pop().(*pb.InputFrameDownsync)
 				if pR.inputFrameIdDebuggable(f.InputFrameId) {

frontend/assets/scenes/login.fire

@@ -440,7 +440,7 @@
       "array": [
         0,
         0,
-        344.75930058781137,
+        216.05530045313827,
         0,
         0,
         0,