Checking for collision overlaps when spawning entities with an ECB

Entity Component System (ECS)
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1

Still very new to ECS. But it’s starting to slowly click.

I’m spawning a bunch of obstacles in an entity command buffer, since I’ve read that that’s the correct way to handle entity creation/destruction.

I wanted to figure out how to ensure that the obstacles don’t spawn within each other’s collision bounds. It’s pretty trivial to check to see if a point is colliding with an object once that object has already been instantiated, but how can I do the same thing if that entities instantiation is still queued up in an ECB?

I know I can calculate the bounds of he object based on the size and shape of the prefab, is that really the way to do it?

2 
NativeList<DistanceHit> outHits = new NativeList<DistanceHit>(Allocator.Temp);

//Set on Entity physic custom physics shape on objects you want to check against set the Shapes setting Belongs to 1.

                CollisionFilter overlapSphereCollisionFilter = new CollisionFilter()
                {
                    BelongsTo = 1,
                    CollidesWith = 2,
                    GroupIndex = 0
                };
if (_collisionWorld.OverlapSphere(localToWorld.Position, 2, ref outHits, overlapSphereCollisionFilter))
                {
//Check if any objects exist in ouHits. If there is don't spawn the object. or delete any objects in the way
}

Something like this in a Job should do the trick. Sphere collisions are a fast easy way. I’m sure there’s a lot of ways. I’m unsure of the way your spawning things. might be easier to do a spawn in a double for loop and then do a random offset within limits of your spacing. If you want to get a little fancier look at Poisson disc sampling.