Question two containers may not be the same (aliasing). (?!)

I have received this error

- I create an array of PlayerScore entities using ToEntityArray on PlayerScoreComponent's
- I do a .ForEach() which doesn't involve any entities/components associated with PlayerScore entities
- I got through each entity in the PlayerScoreComponent array and compare the entity's PlayerScoreComponent NetworkId to another brought in NetworkId
- I then Set(entity, PlayerScoreComponent)

I am getting:

Code (CSharp):

1. InvalidOperationException: The writeable ComponentDataFromEntity<PlayerScoreComponent> <>c__DisplayClass_ChangeMaterialOnTriggerEnter.JobData.playerScoreComponent is the same ComponentDataFromEntity<PlayerScoreComponent> as <>c__DisplayClass_ChangeMaterialOnTriggerEnter.JobData._ComponentDataFromEntity_PlayerScoreComponent_3, two containers may not be the same (aliasing).

I am wondering why this comes up. Is it because within a .ForEach() I am working with entities not related to the queried entities?

Full code:

Code (CSharp):

1. protected override void OnUpdate()
2.     {
3.         // var commandBuffer = m_CommandBufferSystem.CreateCommandBuffer();
4.  
5.         // Need this extra variable here so that it can
6.         // be captured by Entities.ForEach loop below
7.         var nonTriggerMask = m_NonTriggerMask;
8.  
9.         //this is where we grab the data for processing
10.         //first we grab an array of all the player score entities
11.         var playerScoreEntities = m_PlayerScores.ToEntityArray(Allocator.TempJob);
12.         //we will need to grab the PlayerScoreComponent from our player score entities to compare values
13.         var playerScoreComponent = GetComponentDataFromEntity<PlayerScoreComponent>();
14.  
15.         //We grab the 1 HighestScore engity
16.         var highestScoreEntities = m_HighestScore.ToEntityArray(Allocator.TempJob);
17.         //We will need to grab the HighestScoreComponent from our highest score entity to compare values
18.         var highestScoreComponent = GetComponentDataFromEntity<HighestScoreComponent>();
19.  
20.         //We are going to use this to pull the GhostOwnerComponent from the bullets in that have the DynamicBuffer of StatefulTriggerEvents
21.         var ghostOwner = GetComponentDataFromEntity<GhostOwnerComponent>();
22.      
23.         //We need to dispose our entities
24.         Entities
25.         .WithDisposeOnCompletion(playerScoreEntities)
26.         .WithDisposeOnCompletion(highestScoreEntities)
27.         .WithName("ChangeMaterialOnTriggerEnter")
28.         .ForEach((Entity e, ref DynamicBuffer<StatefulTriggerEvent> triggerEventBuffer) =>
29.         {
30.             for (int i = 0; i < triggerEventBuffer.Length; i++)
31.             {
32.                 var triggerEvent = triggerEventBuffer[i];
33.                 var otherEntity = triggerEvent.GetOtherEntity(e);
34.  
35.                 // exclude other triggers and processed events
36.                 if (triggerEvent.State == EventOverlapState.Stay || !nonTriggerMask.Matches(otherEntity))
37.                 {
38.                     continue;
39.                 }
40.  
41.                 //this is what happens when the bullet enters
42.                 else if (triggerEvent.State == EventOverlapState.Enter)
43.                 {
44.  
45.                     //We grab the NetworkId of the bullet so we know who to assign points to
46.                     var bulletsPlayerNetworkId = ghostOwner[e].NetworkId;
47.  
48.                     //We start with 0 points to add
49.                     int pointsToAdd = 0;
50.                     if (HasComponent<PlayerTag>(otherEntity))
51.                     {
52.                         //Now we check if the bullet came from the same player
53.                         if (ghostOwner[otherEntity].NetworkId == bulletsPlayerNetworkId)
54.                         {
55.                             //if it is from the same player no points
56.                             return;
57.                         }
58.                         pointsToAdd += 10;
59.                     }
60.  
61.                     if (HasComponent<AsteroidTag>(otherEntity))
62.                     {
63.                         pointsToAdd += 1;
64.                     }
65.                  
66.                     //After updating the points to add we check the PlayerScore entities and find the one with the
67.                     //correct NetworkId so we can update the scores for the layer
68.                     //If the updated score is higher than the highest score it updates the highest score
69.                     for (int j = 0; j < playerScoreEntities.Length; j++)
70.                     {
71.                         var  currentPlayScoreComponent = playerScoreComponent[playerScoreEntities[j]];
72.                         if(currentPlayScoreComponent.networkId == bulletsPlayerNetworkId)
73.                         {
74.                             var newPlayerScore = new PlayerScoreComponent{
75.                                 networkId = currentPlayScoreComponent.networkId,
76.                                 playerName = currentPlayScoreComponent.playerName,
77.                                 currentScore = currentPlayScoreComponent.currentScore + pointsToAdd,
78.                                 highScore = currentPlayScoreComponent.highScore
79.                                 };
80.                             //here we check if the player beat their own high score
81.                             if (newPlayerScore.currentScore > newPlayerScore.highScore)
82.                             {
83.                                 newPlayerScore.highScore = newPlayerScore.currentScore;
84.                             }
85.                             //here we check if the player beat the highest score
86.                             var currentHighScore = highestScoreComponent[highestScoreEntities[0]];
87.                             if (newPlayerScore.highScore > currentHighScore.highestScore)
88.                             {
89.                                 var updatedHighestScore = new HighestScoreComponent {
90.                                     highestScore = newPlayerScore.highScore,
91.                                     playerName = newPlayerScore.playerName
92.                                 };
93.                                 SetComponent<HighestScoreComponent>(highestScoreEntities[0],  updatedHighestScore);
94.                             }
95.                             SetComponent<PlayerScoreComponent>(playerScoreEntities[j], newPlayerScore);
96.                         }
97.                     }
98.                 }
99.                 else
100.                 {
101.                     continue;
102.                 }
103.             }
104.         }).Schedule();
105.  
106.     }

 

You should either use GetComponentDataFromEntity<HighestScoreComponent> or the syntax-sugar version Get/SetComponent<HighestScoreComponent> (and the same for the PlayerScoreComponent). The error is because you have two ComponentDataFromEntity for the same component (one that you created yourself, and another one generated by the Unity code-gen).

 

Sorry I am sure I am being dense but is that not what I am doing in line 13 and 18 in the example above?

If I don't need to create one how do I use the code-gen one?

 

You are using GetComponentDataFromEntity on lines 13 and 18, then on lines 93 and 95 you are using SetComponent (which code-gens another GetComponentDataFromEntity). You should either use the ones you already got in lines 13 and 18, or delete those and only use the SetComponent version.

 

I had no idea that SetComponent == GetComponentData !!! Thank you!

I assume I HAVE to go with GetComponentData instead of SetComponent right? Because I am using GetComponentData within the .ForEach to grab data from an entity.

(I only asked because I am wondering if there are more obvious things I am missing)

 

I would say that Get/SetComponent is the way to go with ForEach... Unless you don't like code-gen magic for some reason.

If you only use GetComponent inside the ForEach it will code-gen properly to a read-only GeComponentDataFromEntity and if you use SetComponent it will use the non-read-only version automatically.

 

This is really great thank you.

So if I use GetComponent I am ALSO allowed to use SetComponent

But if I use GetComponentDataArray then I cannot use SetComponent

Much appreciated