Question Getting Error Attempting CollisionWorld.CastRay

So I'm trying to do a simple parallel scan.

Script that does the scan:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using Unity.Entities;
4. using Unity.Transforms;
5. using Unity.Physics;
6. using Unity.Physics.Systems;
7. using Unity.Mathematics;
8. using Unity.Collections;
9. using Unity.Jobs;
10. using UnityEngine;
11.  
12. public class RayScanner : MonoBehaviour
13. {
14.     // Start is called before the first frame update
15.     void Start(){}
16.  
17.     public void TDRaycast(CollisionWorld collisionWorld)//, NativeList<Unity.Physics.RaycastHit> allHits)
18.     {
19.         float3 RayFrom = new float3(1f, 1f, 1f);
20.         float3 RayTo = new float3(1f, -1f, 1f);
21.  
22.         RaycastInput input = new RaycastInput()
23.         {
24.             Start = RayFrom,
25.             End = RayTo,
26.             Filter = new CollisionFilter()
27.             {
28.                 BelongsTo = ~0u,
29.                 CollidesWith = ~0u, // all 1s, so all layers, collide with everything
30.                 GroupIndex = 0
31.             }
32.         };
33.  
34.         NativeList<Unity.Physics.RaycastHit> allHits = new NativeList<Unity.Physics.RaycastHit>();
35.         collisionWorld.CastRay(input, ref allHits);
36.     }
37. }

Script that creates the job:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using Unity.Entities;
4. using Unity.Transforms;
5. using Unity.Physics;
6. using Unity.Physics.Systems;
7. using Unity.Mathematics;
8. using Unity.Collections;
9. using Unity.Jobs;
10. using UnityEngine;
11.  
12. public class TriangleScanner : MonoBehaviour
13. {
14.     static RayScanner rayCaster;
15.  
16.     // Start is called before the first frame update
17.     void Start()
18.     {
19.         rayCaster = new RayScanner();
20.     }
21.  
22.     // Update is called once per frame
23.     void Update()
24.     {
25.         TriScan();
26.     }
27.  
28.     public struct RayCastJob : IJobParallelFor
29.     {
30.         public float3 from;
31.         public float3 to;
32.         //[ReadOnly] public CollisionWorld collisionWorld;
33.         public CollisionWorld collisionWorld;
34.  
35.         public void Execute(int index)
36.         {
37.             rayCaster.TDRaycast(collisionWorld);
38.         }
39.     }
40.  
41.     public void TriScan()
42.     {
43.         var physicsWorldSystem = World.DefaultGameObjectInjectionWorld.GetExistingSystem<Unity.Physics.Systems.BuildPhysicsWorld>();
44.         var collisionWorld = physicsWorldSystem.PhysicsWorld.CollisionWorld;
45.  
46.         RayCastJob job = new RayCastJob();
47.         job.collisionWorld = collisionWorld;
48.         JobHandle handle = job.Schedule(2, 1);
49.  
50.         handle.Complete();
51.     }
52. }
53.  

I get this error:

Code (csharp):

1.  
2. InvalidOperationException: The native container has been declared as [ReadOnly] in the job, but you are writing to it.
3. ...
4. Unity.Physics.CollisionWorld.CastRay (Unity.Physics.RaycastInput input, Unity.Collections.NativeList`1[Unity.Physics.RaycastHit]& allHits) (at Library/PackageCache/com.unity.physics@0.4.1-preview/Unity.Physics/Collision/World/CollisionWorld.cs:196)
5. RayScanner.TDRaycast (Unity.Physics.CollisionWorld collisionWorld) (at Assets/03_Mapping/TriDotScannng/RayScanner.cs:51)
6. TriangleScanner+RayCastJob.Execute (System.Int32 index) (at Assets/03_Mapping/TriDotScannng/TriangleScanner.cs:37)
7. Unity.Jobs.IJobParallelForExtensions+ParallelForJobStruct`1[T].Execute (T& jobData, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) (at <a1ac446df41c4a67becf2f8317dc1792>:0)
8.  

Is CastRay actually writing to the CollisionWorld? I thought it was only supposed to write to the 'Ref NativeList'.

If I remove the [Read Only] from the CollisionWorld, I get this:

Code (CSharp):

1. IndexOutOfRangeException: Index 0 is out of restricted IJobParallelFor range [1...1] in ReadWriteBuffer.
2. ReadWriteBuffers are restricted to only read & write the element at the job index. You can use double buffering strategies to avoid race conditions due to reading & writing in parallel to the same elements from a job.
3. ...
4. Unity.Physics.CollisionWorld.CastRay (Unity.Physics.RaycastInput input, Unity.Collections.NativeList`1[Unity.Physics.RaycastHit]& allHits) (at Library/PackageCache/com.unity.physics@0.4.1-preview/Unity.Physics/Collision/World/CollisionWorld.cs:196)
5. RayScanner.TDRaycast (Unity.Physics.CollisionWorld collisionWorld) (at Assets/03_Mapping/TriDotScannng/RayScanner.cs:51)
6. TriangleScanner+RayCastJob.Execute (System.Int32 index) (at Assets/03_Mapping/TriDotScannng/TriangleScanner.cs:37)
7. Unity.Jobs.IJobParallelForExtensions+ParallelForJobStruct`1[T].Execute (T& jobData, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) (at <a1ac446df41c4a67becf2f8317dc1792>:0)

And this:

Code (CSharp):

1. InvalidOperationException: The native container has been declared as [ReadOnly] in the job, but you are writing to it.
2. Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle.CheckWriteAndBumpSecondaryVersion
3. ...
4. RayScanner.TDRaycast (Unity.Physics.CollisionWorld collisionWorld) (at Assets/03_Mapping/TriDotScannng/RayScanner.cs:51)
5. TriangleScanner+RayCastJob.Execute (System.Int32 index) (at Assets/03_Mapping/TriDotScannng/TriangleScanner.cs:37)
6. Unity.Jobs.IJobParallelForExtensions+ParallelForJobStruct`1[T].Execute (T& jobData, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) (at <a1ac446df41c4a67becf2f8317dc1792>:0)
7. Unity.Jobs.JobHandle:ScheduleBatchedJobsAndComplete(JobHandle&)
8. Unity.Jobs.JobHandle:Complete()
9. TriangleScanner:TriScan() (at Assets/03_Mapping/TriDotScannng/TriangleScanner.cs:50)
10. TriangleScanner:Update() (at Assets/03_Mapping/TriDotScannng/TriangleScanner.cs:25)

Really not sure what I'm supposed to make of this, as I don't think I'm doing anything too complicated. Any help would be appreciated. Thanks.

 

You need to declare CollisionWorld as [ReadOnly] in your job. That said, you have a bigger problem in this example - you are scheduling a job at a random point in time from the ECS point of view (during a GO update loop). That means you have to be sure all the relevant systems are finished, but also your job is finished before all the relevant systems start. I suggest looking at query samples and creating a system that schedules this job, otherwise you'll get into a lot of synchronization code that you will hardly ever get out of.