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Unity Engine

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Unity Engine

LayerMask

Specifies Layers to use in a Physics.Raycast.
Read time 3 minutesLast updated 5 days ago

Definition

  • Type: Struct
  • Namespace: UnityEngine
  • Assembly: UnityEngine.CoreModule
public struct LayerMask

Remarks

A GameObject can use up to 32 LayerMasks supported by the Editor. The first 8 of these 
Layers
are specified by Unity; the following 24 are controllable by the user.
Bitmasks represent the 32 Layers and define them as 
true
or 
false
. Each bitmask describes whether the 
Layer
is used. As an example, bit 5 can be set to 1 (
true
). This will allow the use of the built-in 
Water
setting.
Edit->Settings->Tags and Layers
option shows the use of the 32 bitmasks. Each 
Layer
is shown with a string setting. As an example 
Built-in Layer 0
is set as 
Default
; 
Built-in Layer 1
is set as 
TransparentFX
. New named 
Layer
s are added above bitmask layer 8. A selected 
GameObject
will show the chosen 
Layer
at top right of the Inspector. The example below has 
User Layer 13
set to "Wall". This causes the assigned 
GameObject
to be treated as part of a building.
In the following script example, Physics.Raycast sends a ray into the world. Camera.main can be rotated around the y-axis and fire a ray. Three GameObjects represent walls that can be hit by the fired ray. Each GameObject has GameObject.layer set to the "Wall" layerMask.
using UnityEngine;// Fire a gun at 3 walls in the scene.//// The Raycast will be aimed in the range of -45 to 45 degrees. If the Ray hits any of the// walls true will be returned . The three walls all have a Wall Layer attached.  The left// and right keys, and the space key, are all used to aim and fire.//// Quad floor based at (0, -0.5, 0), rotated in x by 90 degrees, scale (8, 8, 8).// ZCube wall at (0, 0.5, 6), scale (3, 2, 0.5).// LCube wall at (-3, 0, 3), scale (0.5, 1, 4).// RCube wall at (3, 1.5, 3), scale (1, 4, 4).public class ExampleScript : MonoBehaviour{    private float cameraRotation;    void Start()    {        Camera.main.transform.position = new Vector3(0, 0.5f, 0);        cameraRotation = 0.0f;    }    // Rotate the camera based on what the user wants to look at.    // Avoid rotating more than +/-45 degrees.    void Update()    {        if (Input.GetKey("left"))        {            cameraRotation -= 1f;            if (cameraRotation < -45.0f)            {                cameraRotation = -45.0f;            }        }        if (Input.GetKey("right"))        {            cameraRotation += 1f;            if (cameraRotation > 45.0f)            {                cameraRotation = 45.0f;            }        }        // Rotate the camera        Camera.main.transform.localEulerAngles = new Vector3(0.0f, cameraRotation, 0.0f);    }    void FixedUpdate()    {        Transform transform = Camera.main.transform;        if (Input.GetKeyUp("space"))        {            // Check for a Wall.            LayerMask mask = LayerMask.GetMask("Wall");            // Check if a Wall is hit.            if (Physics.Raycast(transform.position, transform.forward, 20.0f, mask))            {                Debug.Log("Fired and hit a wall");            }        }    }}
Note: LayerMask is a bitmask. Use LayerMask.GetMask and LayerMask.LayerToName to generate the bitmask.

Properties

Property

Description

valueConverts a layer mask value to an integer value.

Methods

Method

Description

ToStringGiven a layer mask, returns a comma seperated list of the names of the layers in this mask. The names are as defined in either a Builtin or a User Layer in the Tags and Layers manager.

Static Methods

Method

Description

GetMaskGiven a set of layer names as defined by either a Builtin or a User Layer in the Tags and Layers manager, returns the equivalent layer mask for all of them.
LayerToNameGiven a layer number, returns the name of the layer as defined in either a Builtin or a User Layer in the Tags and Layers manager.
NameToLayerGiven a layer name, returns the layer index as defined by either a Builtin or a User Layer in the Tags and Layers manager.

Operators

Operator

Description

LayerMaskImplicitly converts an integer to a LayerMask.