Fixed multi-barrier collision handling in backend.

README.md

@@ -1,7 +1,18 @@
 # Preface 
 
-This project is a demo for a websocket-based input synchronization method inspired by [GGPO](https://www.ggpo.net/).   
-![screenshot-1](./screenshot-1.png)
+This project is a demo for a websocket-based input synchronization method inspired by [GGPO](https://www.ggpo.net/).
+
+_(how input delay roughly works)_
+
+![input_delay_intro](./charts/InputDelayIntro.jpg)
+
+_(how rollback-and-chase in this project roughly works)_
+
+![rollback_and_chase_intro](./charts/RollbackAndChase.jpg)
+
+_(in game screenshot)_
+
+![screenshot-1](./charts/screenshot-1.png)
 
 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.
 
@@ -22,7 +33,7 @@ The video mainly shows the following features.
 - [protobuf CLI](https://developers.google.com/protocol-buffers/docs/downloads) (optional, only for development)
 
 ### Frontend
-- [CocosCreator v2.2.1](https://www.cocos.com/en/cocos-creator-2-2-1-released-with-performance-improvements) (mandatory, **ONLY AVAILABLE on Windows or OSX and should be exactly this version**, DON'T use any other version because CocosCreator is well-known for new versions not being backward incompatible)
+- [CocosCreator v2.2.1](https://www.cocos.com/en/cocos-creator-2-2-1-released-with-performance-improvements) (mandatory, **ONLY AVAILABLE on Windows or OSX and should be exactly this version**, DON'T use any other version because CocosCreator is well-known for new versions not being backward compatible)
 - [protojs](https://www.npmjs.com/package/protojs) (optional, only for development)
 
 ## 1.2 Provisioning
@@ -67,7 +78,7 @@ The easy way is to try out 2 players with test accounts on a same machine.
 - Open one browser instance, visit _http://localhost:7456?expectedRoomId=1_, input `add`on the username box and click to request a captcha, this is a test account so a captcha would be returned by the backend and filled automatically (as shown in the figure below), then click and click to proceed to a matching scene.
 - Open another browser instance, visit _http://localhost:7456?expectedRoomId=1_, input `bdd`on the username box and click to request a captcha, this is another test account so a captcha would be returned by the backend and filled automatically, then click and click to proceed, when matched a `battle`(but no competition rule yet) would start.
 - Try out the onscreen virtual joysticks to move the cars and see if their movements are in-sync.
-![screenshot-2](./screenshot-2.png)
+![screenshot-2](./charts/screenshot-2.png)
 
 ## 2 Troubleshooting
 

battle_srv/models/room.go

@@ -1216,14 +1216,16 @@ func (pR *Room) applyInputFrameDownsyncDynamics(fromRenderFrameId int32, toRende
 				playerCollider := pR.CollisionSysMap[collisionPlayerIndex]
 				if collision := playerCollider.Check(oldDx, oldDy, "Barrier"); collision != nil {
 					playerShape := playerCollider.Shape.(*resolv.ConvexPolygon)
-					barrierShape := collision.Objects[0].Shape.(*resolv.ConvexPolygon)
-					if overlapped, pushbackX, pushbackY := CalcPushbacks(oldDx, oldDy, playerShape, barrierShape); overlapped {
-						Logger.Debug(fmt.Sprintf("Collided & overlapped: player.X=%v, player.Y=%v, oldDx=%v, oldDy=%v, playerShape=%v, toCheckBarrier=%v, pushbackX=%v, pushbackY=%v", playerCollider.X, playerCollider.Y, oldDx, oldDy, ConvexPolygonStr(playerShape), ConvexPolygonStr(barrierShape), pushbackX, pushbackY))
-						dx -= pushbackX
-						dy -= pushbackY
-					} else {
-						Logger.Debug(fmt.Sprintf("Collider BUT not overlapped: player.X=%v, player.Y=%v, oldDx=%v, oldDy=%v, playerShape=%v, toCheckBarrier=%v", playerCollider.X, playerCollider.Y, oldDx, oldDy, ConvexPolygonStr(playerShape), ConvexPolygonStr(barrierShape)))
-					}
+                    for _, obj := range collision.Objects {
+                        barrierShape := obj.Shape.(*resolv.ConvexPolygon)
+                        if overlapped, pushbackX, pushbackY := CalcPushbacks(oldDx, oldDy, playerShape, barrierShape); overlapped {
+                            Logger.Debug(fmt.Sprintf("Collided & overlapped: player.X=%v, player.Y=%v, oldDx=%v, oldDy=%v, playerShape=%v, toCheckBarrier=%v, pushbackX=%v, pushbackY=%v", playerCollider.X, playerCollider.Y, oldDx, oldDy, ConvexPolygonStr(playerShape), ConvexPolygonStr(barrierShape), pushbackX, pushbackY))
+                            dx -= pushbackX
+                            dy -= pushbackY
+                        } else {
+                            Logger.Debug(fmt.Sprintf("Collided BUT not overlapped: player.X=%v, player.Y=%v, oldDx=%v, oldDy=%v, playerShape=%v, toCheckBarrier=%v", playerCollider.X, playerCollider.Y, oldDx, oldDy, ConvexPolygonStr(playerShape), ConvexPolygonStr(barrierShape)))
+                        }
+                    } 
 				}
 				playerCollider.X += dx
 				playerCollider.Y += dy

frontend/assets/scenes/login.fire

@@ -440,7 +440,7 @@
       "array": [
         0,
         0,
-        216.05530045313827,
+        209.73151519075364,
         0,
         0,
         0,