fix: bullet explosion desync [MTT-5080]

Basic/2DSpaceShooter/Assets/Prefabs/Bullet.prefab

@@ -14,8 +14,6 @@ GameObject:
   - component: {fileID: 5800000}
   - component: {fileID: 11400004}
   - component: {fileID: -4113703611147433057}
-  - component: {fileID: -2419440837048175228}
-  - component: {fileID: -7548598001898569089}
   m_Layer: 0
   m_Name: Bullet
   m_TagString: Untagged
@@ -33,6 +31,7 @@ Transform:
   m_LocalRotation: {x: 0, y: 0, z: 0, w: 1}
   m_LocalPosition: {x: 17.05494, y: -1.1583278, z: 0}
   m_LocalScale: {x: 0.6, y: 0.6, z: 0.6}
+  m_ConstrainProportionsScale: 0
   m_Children:
   - {fileID: 6681543778280045604}
   - {fileID: 2541587719488337929}
@@ -51,6 +50,7 @@ SpriteRenderer:
   m_CastShadows: 0
   m_ReceiveShadows: 0
   m_DynamicOccludee: 1
+  m_StaticShadowCaster: 0
   m_MotionVectors: 1
   m_LightProbeUsage: 0
   m_ReflectionProbeUsage: 0
@@ -157,45 +157,6 @@ MonoBehaviour:
   AlwaysReplicateAsRoot: 0
   DontDestroyWithOwner: 0
   AutoObjectParentSync: 0
---- !u!114 &-2419440837048175228
-MonoBehaviour:
-  m_ObjectHideFlags: 0
-  m_CorrespondingSourceObject: {fileID: 0}
-  m_PrefabInstance: {fileID: 0}
-  m_PrefabAsset: {fileID: 0}
-  m_GameObject: {fileID: 100000}
-  m_Enabled: 1
-  m_EditorHideFlags: 0
-  m_Script: {fileID: 11500000, guid: e96cb6065543e43c4a752faaa1468eb1, type: 3}
-  m_Name: 
-  m_EditorClassIdentifier: 
-  SyncPositionX: 1
-  SyncPositionY: 1
-  SyncPositionZ: 1
-  SyncRotAngleX: 1
-  SyncRotAngleY: 1
-  SyncRotAngleZ: 1
-  SyncScaleX: 1
-  SyncScaleY: 1
-  SyncScaleZ: 1
-  PositionThreshold: 0.001
-  RotAngleThreshold: 0.01
-  ScaleThreshold: 0.01
-  InLocalSpace: 0
-  Interpolate: 1
-  CanCommitToTransform: 0
---- !u!114 &-7548598001898569089
-MonoBehaviour:
-  m_ObjectHideFlags: 0
-  m_CorrespondingSourceObject: {fileID: 0}
-  m_PrefabInstance: {fileID: 0}
-  m_PrefabAsset: {fileID: 0}
-  m_GameObject: {fileID: 100000}
-  m_Enabled: 1
-  m_EditorHideFlags: 0
-  m_Script: {fileID: 11500000, guid: 80d7c879794dfda4687da0e400131852, type: 3}
-  m_Name: 
-  m_EditorClassIdentifier: 
 --- !u!1 &1734169577680067239
 GameObject:
   m_ObjectHideFlags: 0
@@ -223,6 +184,7 @@ Transform:
   m_LocalRotation: {x: -0, y: -0, z: -0, w: 1}
   m_LocalPosition: {x: 0, y: 0, z: 0}
   m_LocalScale: {x: 1.6666665, y: 1.6666665, z: 1.6666665}
+  m_ConstrainProportionsScale: 0
   m_Children: []
   m_Father: {fileID: 400000}
   m_RootOrder: 0
@@ -239,6 +201,7 @@ TrailRenderer:
   m_CastShadows: 0
   m_ReceiveShadows: 1
   m_DynamicOccludee: 1
+  m_StaticShadowCaster: 0
   m_MotionVectors: 0
   m_LightProbeUsage: 0
   m_ReflectionProbeUsage: 0
@@ -361,6 +324,7 @@ Transform:
   m_LocalRotation: {x: -0, y: -0, z: -0, w: 1}
   m_LocalPosition: {x: 0, y: 0, z: 0}
   m_LocalScale: {x: 0.6784176, y: 0.6784176, z: 0.6784176}
+  m_ConstrainProportionsScale: 0
   m_Children: []
   m_Father: {fileID: 400000}
   m_RootOrder: 2
@@ -376,6 +340,7 @@ SpriteRenderer:
   m_CastShadows: 0
   m_ReceiveShadows: 0
   m_DynamicOccludee: 1
+  m_StaticShadowCaster: 0
   m_MotionVectors: 1
   m_LightProbeUsage: 0
   m_ReflectionProbeUsage: 0
@@ -443,6 +408,7 @@ Transform:
   m_LocalRotation: {x: -0, y: -0, z: -0, w: 1}
   m_LocalPosition: {x: 0, y: 0, z: 0}
   m_LocalScale: {x: 1.2764332, y: 1.2764332, z: 1.2764332}
+  m_ConstrainProportionsScale: 0
   m_Children: []
   m_Father: {fileID: 400000}
   m_RootOrder: 1
@@ -459,6 +425,7 @@ TrailRenderer:
   m_CastShadows: 0
   m_ReceiveShadows: 1
   m_DynamicOccludee: 1
+  m_StaticShadowCaster: 0
   m_MotionVectors: 0
   m_LightProbeUsage: 0
   m_ReflectionProbeUsage: 0

Basic/2DSpaceShooter/Assets/Scripts/Bullet.cs

@@ -38,6 +38,26 @@ private void DestroyBullet()
         NetworkObject.Despawn(true);
     }
 
+    public void SetVelocity(Vector2 velocity)
+    {
+        if (IsServer)
+        {
+            var bulletRb = GetComponent<Rigidbody2D>();
+            bulletRb.velocity = velocity;
+            SetVelocityClientRpc(velocity);
+        }
+    }
+
+    [ClientRpc]
+    void SetVelocityClientRpc(Vector2 velocity)
+    {
+        if (!IsHost)
+        {
+            var bulletRb = GetComponent<Rigidbody2D>();
+            bulletRb.velocity = velocity;
+        }
+    }
+
     void OnCollisionEnter2D(Collision2D other)
     {
         var otherObject = other.gameObject;

Basic/2DSpaceShooter/Assets/Scripts/ShipControl.cs

@@ -196,23 +196,24 @@ void Fire(Vector3 direction)
     {
         fireSound.Play();
 
-        int damage = 5;
+        var damage = 5;
         if (QuadDamageTimer.Value > NetworkManager.ServerTime.TimeAsFloat)
         {
             damage = 20;
         }
 
-        bool bounce = BounceTimer.Value > NetworkManager.ServerTime.TimeAsFloat;
+        var bounce = BounceTimer.Value > NetworkManager.ServerTime.TimeAsFloat;
 
-        GameObject bullet = m_ObjectPool.GetNetworkObject(BulletPrefab).gameObject;
-        bullet.transform.position = transform.position + direction;
+        var bulletGo = m_ObjectPool.GetNetworkObject(BulletPrefab).gameObject;
+        bulletGo.transform.position = transform.position + direction;
 
-        var bulletRb = bullet.GetComponent<Rigidbody2D>();
         var velocity = m_Rigidbody2D.velocity;
         velocity += (Vector2)(direction) * 10;
-        bulletRb.velocity = velocity;
-        bullet.GetComponent<Bullet>().Config(this, damage, bounce, m_BulletLifetime);
-        bullet.GetComponent<NetworkObject>().Spawn(true);
+        bulletGo.GetComponent<NetworkObject>().Spawn(true);
+        var bullet = bulletGo.GetComponent<Bullet>();
+        bullet.Config(this, damage, bounce, m_BulletLifetime);
+        bullet.SetVelocity(velocity);
+
     }
 
     void Update()

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## [unreleased] - yyyy-mm-dd
 
+### 2DSpaceShooter
+
+### Fixed
+- Fixing bullet explosion desync (#89). Bullet explosion vfx were happening too early on clients because of NetworkTransform's interpolation. Bullets are now no longer synchronised by NetworkTransforms and instead only have their velocity set through client rpcs when they are spawned. Since they are no longer interpolated, they are not lagging behind the server and are at the correct position when they receive the despawn message from the server.
+
 ## [1.1.0] - 2022-12-13
 
 ### Client Driven