Reflect velocity during CollisionEvent

I pulled the Collision Event from the Physics Example project. I wanted to add reflecting the incoming velocity as an option instead of just applying the impulse.

However, when I debug my code, it seems like the object(Ball) is colliding multiple times. Is there a way to avoid this?


This is what I am doing:

Code (CSharp):

1.    
2.     [UpdateAfter(typeof(EndFramePhysicsSystem))]
3.     public class CollisionEventSystem : JobComponentSystem
4.     {
5.         private BuildPhysicsWorld _physicsWorld;
6.         private StepPhysicsWorld _stepPhysicsWorld;
7.         private EntityQuery _impluseGroup;
8.  
9.         protected override void OnCreate()
10.         {
11.             _physicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
12.             _stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
13.             _impluseGroup = GetEntityQuery(new EntityQueryDesc {
14.                 All = new ComponentType[] { typeof(CollisionEventImpulse) }
15.             });
16.         }
17.  
18.         protected override JobHandle OnUpdate(JobHandle inputDependencies)
19.         {
20.             var handle = new CollisionEventSystemJob() {
21.                 ColliderEventImpulseGroup = GetComponentDataFromEntity<CollisionEventImpulse>(true),
22.                 PhysicsVelocityGroup = GetComponentDataFromEntity<PhysicsVelocity>()
23.             }.Schedule(_stepPhysicsWorld.Simulation, ref _physicsWorld.PhysicsWorld, inputDependencies);
24.  
25.             handle.Complete();
26.             return handle;
27.         }
28.     }
29.  
30.     [BurstCompile]
31.     struct CollisionEventSystemJob : ICollisionEventsJob
32.     {
33.         [ReadOnly] public ComponentDataFromEntity<CollisionEventImpulse> ColliderEventImpulseGroup;
34.         public ComponentDataFromEntity<PhysicsVelocity> PhysicsVelocityGroup;
35.  
36.         public void Execute(CollisionEvent collisionEvent)
37.         {
38.             var entityA = collisionEvent.Entities.EntityA;
39.             var entityB = collisionEvent.Entities.EntityB;
40.  
41.             var isBodyADynamic = PhysicsVelocityGroup.Exists(entityA);
42.             var isBodyBDynamic = PhysicsVelocityGroup.Exists(entityB);
43.  
44.             var isBodyARepulser = ColliderEventImpulseGroup.Exists(entityA);
45.             var isBodyBRepulser = ColliderEventImpulseGroup.Exists(entityB);
46.  
47.             if (isBodyARepulser && isBodyBDynamic) {
48.                 var impulseComponent = ColliderEventImpulseGroup[entityA];
49.                 var velocityComponent = PhysicsVelocityGroup[entityB];
50.  
51.                 if (impulseComponent.Reflect == 1) {
52.                     velocityComponent.Linear = reflect(velocityComponent.Linear, collisionEvent.Normal);
53.                 }
54.                 else {
55.                     velocityComponent.Linear = impulseComponent.Impulse;
56.                 }
57.  
58.                 PhysicsVelocityGroup[entityB] = velocityComponent;
59.             }
60.  
61.             if (isBodyBRepulser && isBodyADynamic) {
62.                 var impulseComponent = ColliderEventImpulseGroup[entityB];
63.                 var velocityComponent = PhysicsVelocityGroup[entityA];
64.  
65.                 if (impulseComponent.Reflect == 1) {
66.                     velocityComponent.Linear = reflect(velocityComponent.Linear, collisionEvent.Normal);
67.                 }
68.                 else {
69.                     velocityComponent.Linear = impulseComponent.Impulse;
70.                 }
71.  
72.                 PhysicsVelocityGroup[entityA] = velocityComponent;
73.             }
74.         }
75.     }
76.  

 

Using your code as a template, I am currently trying to change the speed value of my entities (https://forum.unity.com/threads/update-component-data-on-collision.803874/).

Any idea why my update isn't working? In case you solved your issue: How did you fix it?

 

I should reply to this thread and say I figured it out myself. Instead of using the velocity component's linear property, i generated my own direction vector and set a constant magnitude