Physics OverlapSphere layermask not working?

Can someone please help

Following Code

Code (CSharp):

1. GameObject[] possibleTargets = System.Array.ConvertAll(Physics.OverlapSphere(transform.position, sightDistance, 8), col => col.gameObject);

only works when I don't use a layermask... the 8.

I made sure to create a new layer at the 8th place and apply it to the GameObjects I want involved... but it does not return any GameObjects

 

When I try it with layermask 9 it returns a lot of gameobjects, even those not in layer 9...

 

Ok, of course I search for hours before posting a question and then find the answer soon after.

In order for the layermask to work properly you have to type it as 1<<8 or 1<<9 for some reason which I don't want to read any further into at the moment.

https://stackoverflow.com/questions/58663058/physics-overlapsphere-not-detecting-colliders-correctly

 

In Unity you have 32 layers. The layer mask lets you choose any combination of these layers.
In C#, the int type is 32 bits. Each bit corresponds to a layer.
By doing 1 << 9, you are setting only bit 9, and therefore mask out all other layers except 9.

If you use int.MaxValue as your layer mask, all 32 layers will be cast against because all 32 bits are set.

 

Wow thank you!
Just to try and clarify,
1) if I just type the number 11 in the layermask spot, it will include ALL layers up to 11? If so, why was 9 returning everything but 8 returning nothing?
2) Can I choose different layers by doing something like 1<<3<<6<<7 ?

 

1) Nope, that's not how binary works. Each bit in binary is a power of two.
1 2 4 8 16 32 64 128 256 512 (etc)

So the number "11" would be a combination of
Bit 1 (1)
Bit 2 (2)
Bit 4 (8)
1 + 2 + 8 = 11

You'd be selecting layers 1 2 and 4 by using "11" here.

2) You can use a binary or operator (|)
ex. int mask = 1 << 2 | 1 << 3;
This would choose layers 2 and 3.

You can also use names if you'd like, by using LayerMask.GetMask

 

The layer mask parameter is expecting a bitmask, not a layer number, so simply passing in the number of a layer will not work.

If you don't know how bitmasks work, the easiest thing to do is declare a public LayerMask variable as a class member, like so

public LayerMask myLayerMask;

Then pass myLayerMask in to OverlapSphere instead of 8. Unity will render a layer-selecting widget in the inspector, which you can use to select which layers you want and Unity will create the LayerMask value behind the scenes.