LayerMask, Add Another Layer After Run

Can I alter the values excepted by a LayerMask post run?


So, in the inspector I set LayerMask to except thisLayer, but after run, can I get it to accept thisLayer and thatLayer??

 

LayerMask both = maskA | maskB

 

Is that actual code?

 

just missing a ;

 

I feel my chain is being pulled for some reason.

Away from ' puter.



Usually a Class object would be assigned in code as....

Code (csharp):

1.  
2. int[] thisInt = new int[2]{1,2};
3.  

The reason I say an int array is that my layerMask, toting multiple layers is in itself an array.

 

layer += newLayer; simple as that. BUT you have to make sure that the layer you want to add does not already exist or else the value of the layer can be different for instance. Suppose you wanted to add a PlayerLayer to a gameObject at run time, now suppose PlayerLayer is 3. Well, if the layer does not already exist layer+=PlayerLayer would be valid and add 3 to the Layer index. BUT if PlayerLayer 3 already exists, layer+=PlayerLayer will result in 3*3 which will be altered to 9. So, if there IS a layer with layer value 9 that will get added BUT if 9 does not exists it will throw an out of bounds exception. I know this because I built my own UI and I wanted to alter the camera layer at run time and I know how Layers work now so yeah if you need any help just let me know.

 

No, you cannot just add layermasks, because they are bitmasks, so you must use bitwise operators to combine them properly.

And layermask isn't a class (or an array...), its a value, so you don't have to 'new' it.

 

When I tried

thisLayerMask += 13; I got every layer, that is defined, added to the layerMask.

When I did this...
thisLayerMask += "thisLayer";, i get an error pre run.


How do you insure layer 10, thisLayer, is added and none else?

 

Layermask newLayers = oldLayers | (1<<10);

 

Ok,
So what is that line telling the computer exactly?

 

http://en.wikipedia.org/wiki/Bitwise_operation

In short, flip the 10th zero into a one (unless it's already a one, in which case, do nothing)

 

So would (1<<11) set the layer mask to take in layer 11?

 

(1<<11) is a mask for 'only layer 11'
bitwise OR | with some otherMask to include 11 with the layers of otherMask

 

So, in this case, what is old layers? For instance if I originally only had layer 10, or thatLayer activated.

 

wow... handholding much?
oldLayers is whatever layermask you have that you want to add layer 10 to.
If you are setting layers in the inspector then its probably something like

Code (CSharp):

1. public LayerMask myMask;

And then you are probably doing somthing like

Code (CSharp):

1. physics.raycast(ray, distance, myMask)

But, myMask only has layers 8 and 9 set, so you want to add layer 10 into it, so you do

Code (CSharp):

1. myMask = myMask | (1<<10)

 

Thanks mom.

::
Really appreciate it.
I have never done this before and unfamiliar with the bit operations. What other areas that are common in Unity might I use them?


And what yah making for dinner? I hope its spaghetti!

 

It's a Sunday, Sunday is always a roast.

Layermasks are also used for camera culling.
But bitwise math can be used for quite a few things, hashing, psudorandom generators, bit flags

 

Hm.
Interesting.


Can't wait.
Can I bring a friend??

 

How do you properly remove a layer?
I had been using this, but it is not working.

Code (csharp):

1.  
2. layerMask ^= (0<<10);
3.  

Thanks

 

^ is XOR, which isnt what you want. Better to use AND NOT

layermask = layermask & ~(1<<x)

ps. 0<<10 is still 0

 

Hm.
Ok, thanks.