Question You are trying to schedule a new job CollisionSystem:CollisionSystemJob, which reads from the same U

I'm trying to store collisions inside a buffer for entities that implement my CollisionBuffer:

Code (CSharp):

1. using Unity.Entities;
2. using Unity.Jobs;
3. using Unity.Physics;
4. using Unity.Physics.Systems;
5.  
6. [UpdateAfter(typeof(ExportPhysicsWorld))]
7. public partial class CollisionSystem : SystemBase
8. {
9.  
10.  
11.     private struct CollisionSystemJob : ICollisionEventsJob
12.     {
13.         public BufferFromEntity<CollisionBuffer> collisions;
14.         public void Execute(CollisionEvent collisionEvent)
15.         {
16.             if (collisions.HasComponent(collisionEvent.EntityA))
17.             {
18.                 collisions[collisionEvent.EntityA].Add(new CollisionBuffer() { entity = collisionEvent.EntityB });
19. }
20.             if (collisions.HasComponent(collisionEvent.EntityB))
21.             {
22.                 collisions[collisionEvent.EntityB].Add(new CollisionBuffer() { entity = collisionEvent.EntityA });
23.             }
24.         }
25.     }
26.  
27.     protected override void OnUpdate()
28.     {
29.         var pw = World.GetOrCreateSystem<BuildPhysicsWorld>().PhysicsWorld;
30.         var sim = World.GetOrCreateSystem<StepPhysicsWorld>().Simulation;
31.  
32.         Entities.ForEach((DynamicBuffer<CollisionBuffer> collisions) =>
33.         {
34.             collisions.Clear();
35.         }).Run();
36.  
37.         JobHandle colJobHandle = new CollisionSystemJob()
38.         {
39.             collisions = GetBufferFromEntity<CollisionBuffer>()
40.         }.Schedule(sim, this.Dependency);
41.         colJobHandle.Complete();
42.     }
43. }
44.  
45.  

Here's the error that I'm getting:

Code (CSharp):

1.  The previously scheduled job Solver:ParallelApplyGravityAndCopyInputVelocitiesJob writes to the Unity.Collections.NativeArray`1[Unity.Physics.Velocity] ParallelApplyGravityAndCopyInputVelocitiesJob.InputVelocities. You are trying to schedule a new job CollisionSystem:CollisionSystemJob, which reads from the same Unity.Collections.NativeArray`1[Unity.Physics.Velocity] (via CollisionSystemJob.EventReader.m_InputVelocities). To guarantee safety, you must include Solver:ParallelApplyGravityAndCopyInputVelocitiesJob as a dependency of the newly scheduled job.

I have been googling this issue and it seems like for some people [UpdateAfter(typeof(ExportPhysicsWorld))] managed to solve it. But it isn't true in my case.

While we are at it, why doesn't unity have a system similar to this one inside their physics package? it seems very basic.

 

Right now I'm using the attributes:

[UpdateAfter(typeof(ExportPhysicsWorld))]
[UpdateBefore(typeof(EndFramePhysicsSystem))]

still experiencing this issue without any lead to what may cause it.

 

In entities 0.51 you might need this, or the write version. I think you need this in all systems that interact with the physics. If you are still on 0.17, I don't know whats going wrong.

protected override void OnStartRunning()
{
this.RegisterPhysicsRuntimeSystemReadOnly();
}