Must include HavokSimulation:SyncJob as a dependency

Questions & Answers
1

I am trying to make limit my player’s jumping when he is not colliding with the floor

Here’s my system for doing this:

    [UpdateBefore(typeof(PhysicsStep))]   
    public class TogglePLinearImpulseOnFloorCollisionSystem : JobComponentSystem
    {
        EntityQuery FloorGroup;
        EntityQuery CharacterGroup;
        BuildPhysicsWorld buildPhysicsWorld;
        StepPhysicsWorld stepPhysicsWorld;

        protected override void OnCreate()
        {
            FloorGroup = GetEntityQuery(typeof(FloorTag));
            CharacterGroup = GetEntityQuery(typeof(ToggleInputLinearImpulseOnFloorCollisionTag));
            base.OnCreate();
            buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
            stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
        }
        protected override JobHandle OnUpdate(JobHandle inputDeps)
        {
            var jobHandle = new TogglePLinearImpulseOnFloorCollisionJob()
            {
                FloorGroup = GetComponentDataFromEntity<FloorTag>(true),
                CharacterGroup = GetComponentDataFromEntity<ToggleInputLinearImpulseOnFloorCollisionTag>(true),
                PLinearImpulseGroup = GetComponentDataFromEntity<PLinearImpulse>()
            }.Schedule(stepPhysicsWorld.Simulation, ref buildPhysicsWorld.PhysicsWorld, inputDeps, stepPhysicsWorld.FinalSimulationJobHandle);
            return jobHandle;
        }
    }

I get no result except for this error:

InvalidOperationException: The previously scheduled job HavokSimulation:SyncJob reads from the Unity.Collections.NativeArray`1[Unity.Physics.MotionVelocity] SyncJob.World.DynamicsWorld.m_MotionVelocities. You are trying to schedule a new job Solver:ParallelApplyGravityAndCopyInputVelocitiesJob, which writes to the same Unity.Collections.NativeArray`1[Unity.Physics.MotionVelocity] (via ParallelApplyGravityAndCopyInputVelocitiesJob.MotionVelocities). To guarantee safety, you must include HavokSimulation:SyncJob as a dependency of the

There is also a compiler error despite having the reference in the assembly definition:

stepPhysicsWorld.FinalSimulationJobHandle -> Unity.Physics.IBodyPairsJobExtensions.HAVOK_PHYSICS_MISSING_FROM_ASMDEF
2

Hey guys, I found the solution.

Mistake number 1: [UpdateInGroup(typeof(FixedStepSimulationSystemGroup))] should be used instead of [UpdateBefore(typeof(PhysicsStep))].

Mistake number 2: no need for FinalSimulationJobHandle.

Mistake number 3: A JobHandle should be completed before being returned, as it needs to finish before the next physics step. ( jobHandle.Complete() )

I’m posting the full final code of the script, as I don’t want anyone else to frustrate over this:

    [UpdateInGroup(typeof(FixedStepSimulationSystemGroup))]
    public class TogglePLinearImpulseOnFloorCollisionSystem : JobComponentSystem
    {
        EntityQuery FloorGroup;
        EntityQuery CharacterGroup;
        BuildPhysicsWorld buildPhysicsWorld;
        StepPhysicsWorld stepPhysicsWorld;

        protected override void OnCreate()
        {
            base.OnCreate();
            FloorGroup = GetEntityQuery(typeof(FloorTag));
            CharacterGroup = GetEntityQuery(typeof(ToggleInputLinearImpulseOnFloorCollisionTag));
            buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
            stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
        }
        protected override JobHandle OnUpdate(JobHandle inputDeps)
        {
            var jobHandle = new TogglePLinearImpulseOnFloorCollisionJob()
            {
                FloorGroup = GetComponentDataFromEntity<FloorTag>(true),
                CharacterGroup = GetComponentDataFromEntity<ToggleInputLinearImpulseOnFloorCollisionTag>(true),
                PLinearImpulseGroup = GetComponentDataFromEntity<PLinearImpulse>()
            }.Schedule(stepPhysicsWorld.Simulation, ref buildPhysicsWorld.PhysicsWorld, inputDeps);
            jobHandle.Complete();

            return jobHandle;
        }
    }

    [BurstCompile]
    struct TogglePLinearImpulseOnFloorCollisionJob : ICollisionEventsJobBase
    {
        [ReadOnly] public ComponentDataFromEntity<FloorTag> FloorGroup;
        [ReadOnly] public ComponentDataFromEntity<ToggleInputLinearImpulseOnFloorCollisionTag> CharacterGroup;
        public ComponentDataFromEntity<PLinearImpulse> PLinearImpulseGroup;

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

            var bodyAIsCharacter = CharacterGroup.HasComponent(entityA);
            var bodyBIsCharacter = CharacterGroup.HasComponent(entityB);

            var bodyAIsFloor = FloorGroup.HasComponent(entityA);
            var bodyBIsFloor = FloorGroup.HasComponent(entityB);

            var collisionCase = 
                (Convert.ToByte(bodyAIsFloor) << 0) + 
                (Convert.ToByte(bodyBIsFloor) << 1) + 
                (Convert.ToByte(bodyAIsCharacter) << 2) + 
                (Convert.ToByte(bodyBIsCharacter) << 3);
            var pLinearImpulseComponent = new PLinearImpulse();

            switch (collisionCase)
            {
                case (1 << 0) + (1 << 3):
                    pLinearImpulseComponent = PLinearImpulseGroup[entityB];
                    pLinearImpulseComponent.CanImpulse = true;
                    PLinearImpulseGroup[entityB] = pLinearImpulseComponent;
                    break;
                case (1 << 1) + (1 << 2):
                    pLinearImpulseComponent = PLinearImpulseGroup[entityA];
                    pLinearImpulseComponent.CanImpulse = true;
                    PLinearImpulseGroup[entityA] = pLinearImpulseComponent;
                    break;
            }
        }
    }