fix: Invaders hit fx not replicated on player & enemy bullets (#113)

* player and enemy bullet send client rpcs to spawn hit FX

* redundant server side checks removed, spawn/despawn method usage parity

* formatting

Basic/Invaders/Assets/Scripts/EnemyBullet.cs

@@ -1,9 +1,9 @@
-using Unity.Mathematics;
+using System;
 using Unity.Netcode;
 using UnityEngine;
 using UnityEngine.Assertions;
 
-public class EnemyBullet : MonoBehaviour
+public class EnemyBullet : NetworkBehaviour
 {
     private const float k_YBoundary = -4.0f;
 
@@ -16,55 +16,82 @@ public class EnemyBullet : MonoBehaviour
     [SerializeField]
     ParticleSystem m_ShieldExplosionParticle;
 
-    private void Start()
+    void Awake()
     {
-        Assert.IsTrue(InvadersGame.Singleton);
-        Assert.IsTrue(NetworkManager.Singleton);
+        enabled = false;
+    }
 
-        if(InvadersGame.Singleton)
+    public override void OnNetworkSpawn()
+    {
+        enabled = IsServer;
+
+        if (!IsServer)
+        {
+            return;
+        }
+
+        Assert.IsTrue(InvadersGame.Singleton);
+
+        if (InvadersGame.Singleton)
+        {
             InvadersGame.Singleton.isGameOver.OnValueChanged += OnGameOver;
         }
+    }
 
     private void Update()
     {
-        if (!NetworkManager.Singleton.IsServer) return;
         transform.Translate(0, -m_TravelSpeed * Time.deltaTime, 0);
 
-        if (transform.position.y < k_YBoundary) Destroy(gameObject);
+        if (transform.position.y < k_YBoundary)
+        {
+            NetworkObject.Despawn();
+        }
     }
 
-    private void OnDestroy()
+    public override void OnNetworkDespawn()
     {
-        if (InvadersGame.Singleton) InvadersGame.Singleton.isGameOver.OnValueChanged -= OnGameOver;
+        if (InvadersGame.Singleton)
+        {
+            InvadersGame.Singleton.isGameOver.OnValueChanged -= OnGameOver;
+        }
     }
 
     private void OnTriggerEnter2D(Collider2D collider)
     {
-        if (!NetworkManager.Singleton.IsServer)
+        // several OnTriggerEnter2D calls may be invoked in the same frame (for different Colliders), so we check if
+        // we're spawned to make sure we don't trigger hits for already despawned bullets
+        if (!IsServer || !IsSpawned)
             return;
 
         var hitPlayer = collider.gameObject.GetComponent<PlayerControl>();
         if (hitPlayer != null)
         {
+            NetworkObject.Despawn();
             hitPlayer.HitByBullet();
-            Destroy(gameObject);
             return;
         }
 
         var hitShield = collider.gameObject.GetComponent<Shield>();
         if (hitShield != null)
         {
+            SpawnExplosionVFXClientRpc(transform.position, Quaternion.identity);
+
             Destroy(hitShield.gameObject);
-            Destroy(gameObject);
-            Instantiate(m_ShieldExplosionParticle, transform.position, quaternion.identity);
+            NetworkObject.Despawn();
         }
     }
 
+    [ClientRpc]
+    void SpawnExplosionVFXClientRpc(Vector3 spawnPosition, Quaternion spawnRotation)
+    {
+        Instantiate(m_ShieldExplosionParticle, spawnPosition, spawnRotation);
+    }
+
     private void OnGameOver(bool oldValue, bool newValue)
     {
         enabled = false;
 
         // On game over destroy the bullets
-        if (NetworkManager.Singleton.IsServer) Destroy(gameObject);
+        NetworkObject.Despawn();
     }
 }

Basic/Invaders/Assets/Scripts/PlayerBullet.cs

@@ -1,8 +1,8 @@
-using Unity.Mathematics;
+using System;
 using Unity.Netcode;
 using UnityEngine;
 
-public class PlayerBullet : MonoBehaviour
+public class PlayerBullet : NetworkBehaviour
 {
     private const float k_YBoundary = 15.0f;
     public PlayerControl owner;
@@ -15,20 +15,31 @@ public class PlayerBullet : MonoBehaviour
     [SerializeField]
     ParticleSystem m_EnemyExplosionParticle;
 
+    void Awake()
+    {
+        enabled = false;
+    }
+
+    public override void OnNetworkSpawn()
+    {
+        enabled = IsServer;
+    }
+
     private void Update()
     {
-        if (!NetworkManager.Singleton.IsServer) return;
-        
         transform.Translate(0, m_TravelSpeed * Time.deltaTime, 0);
 
         if (transform.position.y > k_YBoundary)
-            if (NetworkManager.Singleton.IsServer)
-                Destroy(gameObject);
+        {
+            NetworkObject.Despawn();
+        }
     }
 
     private void OnTriggerEnter2D(Collider2D collider)
     {
-        if (!NetworkManager.Singleton.IsServer)
+        // several OnTriggerEnter2D calls may be invoked in the same frame (for different Colliders), so we check if
+        // we're spawned to make sure we don't trigger hits for already despawned bullets
+        if (!IsServer || !IsSpawned)
             return;
 
         var hitEnemy = collider.gameObject.GetComponent<EnemyAgent>();
@@ -36,17 +47,13 @@ public class PlayerBullet : MonoBehaviour
         {
             owner.IncreasePlayerScore(hitEnemy.score);
 
-            if (NetworkManager.Singleton.IsServer)
-            {
             // Only the server can despawn a NetworkObject
             hitEnemy.NetworkObject.Despawn();
-            }
             
-            Destroy(gameObject);
+            SpawnExplosionVFXClientRPC(transform.position, Quaternion.identity);
+            
+            NetworkObject.Despawn();
             
-            // this instantiates at the position of the bullet, there is an offset in the Y axis on the 
-            // particle systems in the prefab so it looks like it spawns in the middle of the enemy
-            Instantiate(m_EnemyExplosionParticle, transform.position, quaternion.identity);
             return;
         }
 
@@ -54,7 +61,15 @@ public class PlayerBullet : MonoBehaviour
         if (hitShield != null)
         {
             Destroy(hitShield.gameObject);
-            Destroy(gameObject);
+            NetworkObject.Despawn();
         }
     }
+
+    [ClientRpc]
+    void SpawnExplosionVFXClientRPC(Vector3 spawnPosition, Quaternion spawnRotation)
+    {
+        // this instantiates at the position of the bullet, there is an offset in the Y axis on the 
+        // particle systems in the prefab so it looks like it spawns in the middle of the enemy
+        Instantiate(m_EnemyExplosionParticle, spawnPosition, spawnRotation);
+    }
 }