Raycast won't ignore layer 31

Unity Engine
1

Could someone out there help me with this problem? As far as I am aware, the this should force raycast to ignore objects in layer 31. However, after debugging, lo and behold the hitInfo.collider.gameObject.layer is 31. This should be impossible.

hit = Physics.Raycast(ray, out hitInfo, distance, 1 << 31);
Debug.Log(hitInfo.collider.gameObject.layer); // Outputs 31.

The following also has not worked:

This causes the game to break randomly because this code is used by a lot of classes. Perhaps its ignoring everything but layer 31?

hit = Physics.Raycast(ray, out hitInfo, distance, ~(1 << 31));

This? Ditto. Causes game to freeze up:

hit = Physics.Raycast(ray, out hitInfo, distance, 31);
2

(1<<31) is ONLY objects on 31
~(1<<31) is NOT objects on 31
(31) will not do what you think, and will in fact include layers 1,2,3,45 (its a bitmask!)

just quickly tested and ~(1<<31) ignored a cube on layer 31.

If you really are using all 32 layers, maybe you need to reorganize!

3

I realized the mistake I made just now: I forgot to also include the ignore layer 2. ~(1 << 2 | 1 << 31)

Though, I tried this once and I dismissed it as not working, though it actually DID work, and something else was messed up. I forgot to set up the collision matrix and because I didn’t stuff wasn’t behaving correctly.

Also, the following code caused unity to barf all over the place:

private static readonly LayerMask _ignoreMask = ~(1<<LayerMask.NameToLayer("MyIgnoreLayerName"))  Physics.IgnoreRaycastLayer;

Basically, the instant this value was evaluated (static values are evaluated lazily), some code within native code land would get stuck in an infinite loop.

4

Surely that just evaluates to Physics.IgnoreRaycastLayer, unless MyIgnoreLayerName is the same layer, in which case you get a zero

~(1<<x) // = 1 in all positions except x

(1<<y) // = 1 in only y
       // = 1 in only y