collision system slow

Unity Engine
,
1

Hi

I have this code that works but its quite slow…
if i remove the job.complete it gives errors when i play with some dependency problems
Does anyone know what am i doing wrong or is it just slow ?

There is only like 10-20 explosive entities but there are a lot of blocks like maybe 1-2k
if i commend out this code then the fps goes back to normal

[AlwaysSynchronizeSystem]
[UpdateAfter(typeof(EndFramePhysicsSystem))]
public class ExplosivesCollisionSystem : JobComponentSystem
{
    private BuildPhysicsWorld buildPhysicsWorld;
    private StepPhysicsWorld stepPhysicsWorld;

    protected override void OnCreate()
    {
        base.OnCreate();
        buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
        stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
    }

    [BurstCompile]
    struct DetectCollisionsSystemJob : ICollisionEventsJob
    {
        public ComponentDataFromEntity<ExplosivesComponent> explosivesGroup;
        [ReadOnly] public ComponentDataFromEntity<BlockComponent> blocksGroup;

        public void Execute(CollisionEvent collisionEvent)
        {
            Entity entityA = collisionEvent.Entities.EntityA;
            Entity entityB = collisionEvent.Entities.EntityB;

            bool isBlockA = blocksGroup.Exists(entityA);
            bool isExplosivesA = explosivesGroup.Exists(entityA);
            bool isBlockB = blocksGroup.Exists(entityB);
            bool isExplosivesB = explosivesGroup.Exists(entityB);

            if (isExplosivesA && isBlockB)
            {
                ExplosivesComponent modifiedData = explosivesGroup[entityA];
                if (!modifiedData.DetectedCollision)
                {
                    modifiedData.DetectedCollision = true;
                    explosivesGroup[entityA] = modifiedData;
                }
            }

            if (isBlockA && isExplosivesB)
            {
                ExplosivesComponent modifiedData = explosivesGroup[entityB];
                if (!modifiedData.DetectedCollision)
                {
                    modifiedData.DetectedCollision = true;
                    explosivesGroup[entityB] = modifiedData;
                }
            }
        }
    }

    protected override JobHandle OnUpdate(JobHandle inputDependencies)
    {
        JobHandle jobHandle = new DetectCollisionsSystemJob
        {
            explosivesGroup = GetComponentDataFromEntity<ExplosivesComponent>(false),
            blocksGroup = GetComponentDataFromEntity<BlockComponent>(true),
        }.Schedule(stepPhysicsWorld.Simulation, ref buildPhysicsWorld.PhysicsWorld, inputDependencies);

        jobHandle.Complete();

        return jobHandle;
    }
}
2

You want to UpdateAfter ExportPhysicsWorld and UpdateBefore EndFramePhysicsSystem. Additionally, you want to add your jobHandle to the EndFramePhysicsSystem HandlesToWaitFor list.

3

this thread is duplicated, has been answered. thanks!!!

4

If you’re inheriting SystemBase and using Entities.ForEach(), how do you "add your jobHandle to EndFramePhysicsSystem HandlesToWaitFor list? Sorry noob here… I don’t even know how to get a job handle for a ForEach() loop…

5

So… this is my theory… I “think” SystemBase + Entities.ForEach automatically adds the dependency so we don’t need to call EndFramePhysicsSystem.HandlesToWaitFor.Add().

When I added this above my class declaration, it seems to have stopped the random crashing (crossing my fingers).

[UpdateAfter(typeof(StepPhysicsWorld)), UpdateBefore((typeof(EndFramePhysicsSystem)))]
6

var dependency = Entities.ForeEach().Schedule();

7

Quoting an official answer on this: https://discussions.unity.com/t/777008/9

SystemBase only handles Dependencies automatically for the Entities.ForEach, for any IJobChunk or custom Job (like ICollisionEventsJob) you need to handle manually.

protected override void OnUpdate()
{
    Dependency = new MyCollisionEventsJob
    {
        /*params*/
    }.Schedule(_stepPhysicsWorld.Simulation, ref _buildPhysicsWorld.PhysicsWorld, Dependency);

    _endFramePhysicsSystem.HandlesToWaitFor.Add(Dependency);
}
8

so my final code based on this is as follows
if anyone disagress, please say so :slight_smile:

[UpdateAfter(typeof(StepPhysicsWorld)), UpdateBefore((typeof(EndFramePhysicsSystem)))]
public class ExplosivesCollisionSystem : SystemBase
{
    private BuildPhysicsWorld buildPhysicsWorld;
    private StepPhysicsWorld stepPhysicsWorld;
    private EndFramePhysicsSystem endFramePhysicsSystem;

    protected override void OnCreate()
    {
        base.OnCreate();
        buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
        stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
        endFramePhysicsSystem = World.GetOrCreateSystem<EndFramePhysicsSystem>();

    }

    [BurstCompile]
    struct DetectCollisionsSystemJob : ICollisionEventsJob
    {
        public ComponentDataFromEntity<ExplosivesComponent> explosivesGroup;
        [ReadOnly] public ComponentDataFromEntity<BlockComponentData> blocksGroup;

        public void Execute(CollisionEvent collisionEvent)
        {
            Entity entityA = collisionEvent.Entities.EntityA;
            Entity entityB = collisionEvent.Entities.EntityB;

            bool isBlockA = blocksGroup.Exists(entityA);
            bool isExplosivesA = explosivesGroup.Exists(entityA);
            bool isBlockB = blocksGroup.Exists(entityB);
            bool isExplosivesB = explosivesGroup.Exists(entityB);

            if (isExplosivesA && isBlockB)
            {
                ExplosivesComponent modifiedData = explosivesGroup[entityA];
                if (!modifiedData.DetectedCollision)
                {
                    modifiedData.DetectedCollision = true;
                    explosivesGroup[entityA] = modifiedData;
                }
            }

            if (isBlockA && isExplosivesB)
            {
                ExplosivesComponent modifiedData = explosivesGroup[entityB];
                if (!modifiedData.DetectedCollision)
                {
                    modifiedData.DetectedCollision = true;
                    explosivesGroup[entityB] = modifiedData;
                }
            }
        }
    }

    protected override void OnUpdate()
    {
        Dependency = new DetectCollisionsSystemJob
        {
            explosivesGroup = GetComponentDataFromEntity<ExplosivesComponent>(false),
            blocksGroup = GetComponentDataFromEntity<BlockComponentData>(true),

        }.Schedule(stepPhysicsWorld.Simulation, ref buildPhysicsWorld.PhysicsWorld, Dependency);

        endFramePhysicsSystem.HandlesToWaitFor.Add(Dependency);
    }
}