Question what is UNITY_DOTSRUNTIME?

hi

I am getting an error when building SetSharedComponent of CommandBuffer in ECS using WithBurst.
The error is due to the internal use of Delegate.

I am thinking that if the else side of "#if !UNITY_DOTSRUNTIME" in TypeManager.cs works, the error will not occur in the build.
What is UNITY_DOTSRUNTIME?
Do we need to define it ourselves?

## Burst Error

## Stack Trace

Code (CSharp):

1. at Unity.Entities.FastEquality.GetHashCode(void* dataPtr, Unity.Entities.FastEquality.TypeInfo typeInfo)
2.  
3. at Unity.Entities.FastEquality.GetHashCode(Unity.Physics.PhysicsWorldIndex lhs, Unity.Entities.FastEquality.TypeInfo typeInfo)
4.  
5. at Unity.Entities.TypeManager.GetHashCode(ref Unity.Physics.PhysicsWorldIndex val)
6.  
7. at Unity.Entities.EntityCommandBuffer.IsDefaultObject(ref Unity.Physics.PhysicsWorldIndex component, ref int hashCode)
8.  
9. at Unity.Entities.EntityCommandBuffer.SetSharedComponent(Unity.Entities.EntityCommandBuffer* this, Unity.Entities.Entity e, Unity.Physics.PhysicsWorldIndex component)

## Code
### Self Code
Error Occured => commandBuffer.SetSharedComponent(entity, new PhysicsWorldIndex());

Code (CSharp):

1. Entities
2.   .WithBurst()
3.   .WithAll<TestComponent>()
4.   .ForEach((
5.     Entity entity,
6.     int entityInQueryIndex,
7.     ref TestComponent testComponent,
8.   ) => {
9.     commandBuffer.SetSharedComponent(entity, new PhysicsWorldIndex());
10.   }).Schedule();

### EntityCommandBuffer.cs:2249 => if (IsDefaultObject(ref component, out hashCode))

Code (CSharp):

1. public void SetSharedComponent<T>(Entity e, T component) where T : struct, ISharedComponentData
2. {
3.     EnforceSingleThreadOwnership();
4.     AssertDidNotPlayback();
5.  
6.     int hashCode;
7.     if (IsDefaultObject(ref component, out hashCode))
8.         m_Data->AddEntitySharedComponentCommand<T>(&m_Data->m_MainThreadChain, MainThreadSortKey, ECBCommand.SetSharedComponentData, e, hashCode, null);
9.     else
10.         m_Data->AddEntitySharedComponentCommand<T>(&m_Data->m_MainThreadChain, MainThreadSortKey, ECBCommand.SetSharedComponentData, e, hashCode, component);
11. }

### EntityCommandBuffer.cs:2188 => hashCode = TypeManager.GetHashCode(ref component);

Code (CSharp):

1. static bool IsDefaultObject<T>(ref T component, out int hashCode) where T : struct, ISharedComponentData
2. {
3.     var defaultValue = default(T);
4.  
5.     hashCode = TypeManager.GetHashCode(ref component);
6.     return TypeManager.Equals(ref defaultValue, ref component);
7. }

### TypeManager.cs:760 => return FastEquality.GetHashCode(val, s_FastEqualityTypeInfoList[GetTypeInfo(typeIndex).FastEqualityIndex]);

Code (CSharp):

1. public static int GetHashCode<T>(ref T val) where T : struct
2. {
3. #if !UNITY_DOTSRUNTIME
4.     var typeIndex = GetTypeIndex<T>();
5.     if(IsSharedComponentType(typeIndex))
6.         return FastEquality.GetHashCode(val, s_FastEqualityTypeInfoList[GetTypeInfo(typeIndex).FastEqualityIndex]);
7.  
8.     return FastEquality.GetHashCode(val);
9. #else
10.     return (int)XXHash.Hash32((byte*)UnsafeUtility.AddressOf(ref val), UnsafeUtility.SizeOf<T>());
11. #endif
12. }

### FastEquality.cs:192 => return GetHashCode(UnsafeUtility.AddressOf(ref lhs), typeInfo);

Code (CSharp):

1. public static unsafe int GetHashCode<T>(T lhs, TypeInfo typeInfo) where T : struct
2. {
3.     return GetHashCode(UnsafeUtility.AddressOf(ref lhs), typeInfo);
4. }

### FastEquality.cs:202 => if (typeInfo.GetHashFn != null)

Code (CSharp):

1. public static unsafe int GetHashCode(void* dataPtr, TypeInfo typeInfo)
2. {
3.     if (typeInfo.GetHashFn != null)
4.     {
5.         TypeInfo.GetHashCodeDelegate fn = (TypeInfo.GetHashCodeDelegate)typeInfo.GetHashFn;
6.         return fn(dataPtr);
7.     }
8.  
9.     return Hash32((byte*) dataPtr, typeInfo.TypeSize);
10. }

### FastEquality.cs:152

Code (CSharp):

1. public Delegate GetHashFn;

 

Also curious, but for a different reason I found that I cannot schedule jobs inside a

[BurstCompile]ISystem.OnUpdate

, and when fishing around I found the following in

com.unity.entities

source:

Code (CSharp):

1.  
2.         //disabling burst in dotsrt until burstable scheduling works
3. #if !UNITY_DOTSRUNTIME
4.         [BurstCompile]
5. #endif
6.         public void OnUpdate(ref SystemState state)
7.         {
8.             var localToWorldType = state.GetComponentTypeHandle<LocalToWorld>(true);
9.             var childType = state.GetBufferTypeHandle<Child>(true);
10. // ...

It seems that every

ISystem.OnUpdate

with a scheduled job is guarded with that preprocessor condition. The one above (in

LocalToParentSystem.cs

) is the only one I saw with a comment suggesting some reasoning.

So what's going on here? How does the

UNITY_DOTSRUNTIME

protect from this error? AFAIK

[BurstCompile]

always needs to be removed in this circumstance.

But on that note, if you know anything more about this bug (burstable scheduling) or have seen it in another forum post, please point me in that direction

 

I think it refers to a prototype netcore-based lightweight runtime used by Project Tiny. I don't think there's any supported way to use this currently, especially with Tiny on hold.

https://docs.unity3d.com/Packages/com.unity.tiny@0.23/manual/index.html

 

Thank you all.

I also understand that UNITY_DOTSRUNTIME should not be self-defined!

> @elliotc-unity

With that in mind, I think "#if !UNITY_DOTSRUNTIME" in "TypeManager.cs:760" should be "#if UNITY_DOTSRUNTIME"!

To begin with, does SetSharedComponent support Burst?

 

Thank you for your answer.

I am looking to run the following code

Code (CSharp):

1. Entities
2.   .WithBurst()
3.   .WithAll<TestComponent>()
4.   .ForEach((
5.     Entity entity,
6.     int entityInQueryIndex,
7.     ref TestComponent testComponent,
8.   ) => {
9.     commandBuffer.SetSharedComponent(entity, new PhysicsWorldIndex());
10.   }).Schedule();
11.  

I want the physics operation to occur at a specific timing.

ConvertToEntity processing is slow, so I put an invalid unused value in Physics' worldindex beforehand and ConvertToEntity runs at startup.
I would like to enable the physics operation by putting in a valid value at a specific timing.

In doing so, I have an error when using WithBurst in SetSharedComponent, which is why I asked the question.

 

Does it means at 1.0 shared component no longer support managed data?

 

> All shared components in 0.51 (and in all previous versions of entities) are stored in a single List<object> per world.

Well, now I understand!
Thank you very much.