Delegate 'EntityQueryBuilder.F_E' does not take 3 arguments

Hey guys. I am new to the ECS and want to get into it. I use Ubuntu 19.4. and had some issues with the latest alpha version so I installed Unity 19.1.3f1 today and installed the preview packages some hours ago.

I am trying to recreate the Roll-A-Ball tutorial.

First of all I created two components for my movement

Code (CSharp):

1. public class MovementInput : IComponentData
2. {
3.     public float x;
4.     public float y;
5.     public float z;
6. }
7.  

Code (CSharp):

1. public class MovementSpeed : IComponentData
2. {
3.     public float value;
4. }

After that I created the input and movement system

Code (CSharp):

1. public class PlayerInputSystem : ComponentSystem
2. {
3.     protected override void OnUpdate()
4.     {
5.         float horizontalInput = Input.GetAxis("Horizontal");
6.         float verticalInput = Input.GetAxis("Vertical");
7.  
8.         Entities.ForEach((ref MovementInput movementInput) => {
9.             movementInput.x = horizontalInput;
10.             movementInput.z = verticalInput;
11.         });
12.     }
13. }

Code (CSharp):

1. public class MovementSystem : ComponentSystem
2. {
3.     protected override void OnUpdate()
4.     {
5.         float deltaTime = Time.deltaTime;
6.  
7.         Entities.ForEach((ref Rigidbody rigidbody, ref MovementInput movementInput, ref MovementSpeed movementSpeed) => {
8.             float3 movementDirection = new float3(movementInput.x, movementInput.y, movementInput.z);
9.             rigidbody.AddForce(movementDirection * movementSpeed * deltaTime);
10.         });
11.     }
12. }

So I get these errors

- Assets/Scripts/Systems/PlayerInputSystem.cs(12,26): error CS1661: Cannot convert lambda expression to type 'EntityQueryBuilder.F_E' because the parameter types do not match the delegate parameter types

- Assets/Scripts/Systems/PlayerInputSystem.cs(12,45): error CS1678: Parameter 1 is declared as type 'ref MovementInput' but should be 'Unity.Entities.Entity'

- Assets/Scripts/Systems/MovementSystem.cs(11,26): error CS1593: Delegate 'EntityQueryBuilder.F_E' does not take 3 arguments

and don't know how to fix them. I took this tutorial and I think my code is similiar to his code ..

 

oh ... yeah I forgot to change class to struct ... stupid me. @scobi But I still get the error

in this line

Code (CSharp):

1.  
2. Entities.ForEach((ref MovementInput movementInput, ref MovementSpeed movementSpeed, Rigidbody rigidbody) => {
3.     float3 movementDirection = new float3(movementInput.x, movementInput.y, movementInput.z);
4.     rigidbody.AddForce(movementDirection * movementSpeed.value * deltaTime);
5. });
6.  

and I'm not sure if I can access the rigidbody this way..? The code is just my first try

 

You can...as scobi was saying they created a lot of overloads for all the foreach calls. Sometimes the types of the arguments you're passing into ForEach will need to be in a specific order. In this case it seems they want you to pass classes first before components but after the (optional) entity.

Hopefully at some point we will get some decent documentation about this in particular since the error messages you get from it are truly bad and unhelpful.

 

This is very helpful, thank you. On a related note these names and conventions seem to be slightly different from the new IJobForEach_X conventions which makes it even more confusing. It's nice to know you guys are thinking about rehauling it at least.

 

In IJobForEach C = ComponentData rather than class (yes I understand you can't use classes in jobs), where in ForEach C = Class. In IJobForEach the type ordering is strictly alphabetical based on their assigned letters after entity. In Foreach it just seems kinda...random.

IE:
(ref Translation t, RigidBody r) <- Okay
(ref Translation t, RigidBody r, ref Rotation rot) <- Not Okay
(RigidBody r, ref Translation t, ref Rotation rot) <- Okay

It's basically a guessing game in ForEach (unless I'm missing something), whereas in IJobForEach the rules are clearly defined.

 

thanks guys!

 

UGHH this is so frustrating. Sorry for 'necroing' this thread but this is the best one on the subject and I'd rather bump this than create a new one;

Why does this not work with the _EDB combo?

ForEach<NumPlayersComponentData, PlayerPocketsBufferElement>
((Entity entity, ref NumPlayersComponentData numPlayers, ref PlayerPocketsBufferElement pocket)

I've tried using and removing the ref on the BufferElement. I can get the ComponentData to work by itself and with the entity, but as soon as I try to add buffer elements it doesn't work.

I know I can grab the buffer elements from within the code itself (Which is what I'm currenly doing) but as it stands now I have to use component tags to tag things with the buffer elements in order to pull them into a system. I think this would create issues if I were to try to do parallel jobs though (which I'm not currently)

 

You shouldn't try to include the generic parameters on the ForEach, they will be inferred automatically. And for buffers you need to pass it as

DynamicBuffer<BufferType> buffer

, so something like:

Code (CSharp):

1.         Entities.ForEach((Entity e, ref DynamicBuffer<PlayerPocketsBufferElement> pocket, ref NumPlayersComponent numPlayers) =>
2.         {
3.            
4.         }).Schedule();

The manual page for the ForEach explains everything pretty well, I suggest you review it carefully if you run into trouble.