Update component data on collision

So, I am currently trying to get collisions work in my project.

At the moment I am not even sure if the code that would handle the collision gets executed at all.

All it is supposed to do is set the speed value of a collided entity to 100 but running the code does not do anything.

The simulation contains a few hundred capsules which collide with each other. Everything is working but the collisions do not have the desired effect: Speed up one of the collided entities.

Here is the code I am currently using:

Code (CSharp):

1. using ECS.Components;
2. using Unity.Entities;
3. using Unity.Jobs;
4. using Unity.Physics;
5. using Unity.Physics.Systems;
6.  
7. namespace ECS.Systems
8. {
9.     [UpdateAfter(typeof(EndFramePhysicsSystem))]
10.     public class CollisionEventSystem : JobComponentSystem
11.     {
12.         private BuildPhysicsWorld _physicsWorld;
13.  
14.         private StepPhysicsWorld _stepPhysicsWorld;
15.  
16.         protected override void OnCreate()
17.         {
18.             this._physicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
19.             this._stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
20.         }
21.  
22.         protected override JobHandle OnUpdate(JobHandle inputDeps)
23.         {
24.             var handle = new CollisionEventSystemJob
25.                 {
26.                     SpeedComponentData = GetComponentDataFromEntity<Speed>()
27.                 }
28.                 .Schedule(this._stepPhysicsWorld.Simulation, ref this._physicsWorld.PhysicsWorld, inputDeps);
29.             handle.Complete();
30.             return handle;
31.         }
32.     }
33.    
34.     struct CollisionEventSystemJob : ICollisionEventsJob
35.     {
36.         public ComponentDataFromEntity<Speed> SpeedComponentData;
37.  
38.         public void Execute(CollisionEvent collisionEvent)
39.         {
40.             var entityA = collisionEvent.Entities.EntityA;
41.             // var entityB = collisionEvent.Entities.EntityB;
42.            
43.             if (SpeedComponentData.Exists(entityA)  )
44.             {
45.                 Speed speed = SpeedComponentData[entityA];
46.                 speed.Value = 100;
47.             }
48.         }
49.     }
50. }

Am I missing something here?

 

you need to set the component 'Speed' back to the component data array. i.e:

Code (CSharp):

1.  
2. ...      
3. var entityA = collisionEvent.Entities.EntityA;
4. // var entityB = collisionEvent.Entities.EntityB;
5.          
6.     if (SpeedComponentData.Exists(entityA)  )  {
7.                 Speed speed = SpeedComponentData[entityA];
8.                 speed.Value = 100;
9.               SpeedComponentData[entityA] = speed;
10.       }
11. ....
12.  

 

Oh, that was indeed it. Why is that I wonder? I expected

speed

to be a reference to the actual struct.

In any case: Thank you very much!

 

I just responded in your other thread but duplicating here for others who find this thread:

I I think the write fails because "by default, you cannot write to components in the container in parallel Jobs" https://docs.unity3d.com/Packages/c...Unity.Entities.ComponentDataFromEntity-1.html.