# [name]

Represents a third-order spherical harmonics (SH). Light probes use this class to encode lighting information.

## Constructor

### [name]()

Creates a new instance of [name].

## Properties

### [property:Array coefficients]

An array holding the (9) SH coefficients. A single coefficient is represented as an instance of [page:Vector3].

### [property:Boolean isSphericalHarmonics3]

Read-only flag to check if a given object is of type [name].

## Methods

### [method:this add]( [param:SphericalHarmonics3 sh] )

[page:SphericalHarmonics3 sh] - The SH to add.
Adds the given SH to this instance.

### [method:this addScaledSH]( [param:SphericalHarmonics3 sh], [param:Number scale] )

[page:SphericalHarmonics3 sh] - The SH to add.
[page:Number scale] - The scale factor.
A convenience method for performing [page:.add]() and [page:.scale]() at once.

### [method:SphericalHarmonics3 clone]()

Returns a new instance of [name] with equal coefficients.

### [method:this copy]( [param:SphericalHarmonics3 sh] )

[page:SphericalHarmonics3 sh] - The SH to copy.
Copies the given SH to this instance.

### [method:Boolean equals]( [param:SphericalHarmonics3 sh] )

[page:SphericalHarmonics3 sh] - The SH to compare with.
Returns true if the given SH and this instance have equal coefficients.

### [method:this fromArray]( [param:Array array], [param:Number offset] )

[page:Array array] - The array holding the numbers of the SH coefficients.
[page:Number offset] - (optional) The array offset.
Sets the coefficients of this instance from the given array.

### [method:Vector3 getAt]( [param:Vector3 normal], [param:Vector3 target] )

[page:Vector3 normal] - The normal vector (assumed to be unit length).
[page:Vector3 target] - The result vector.
Returns the radiance in the direction of the given normal.

### [method:Vector3 getIrradianceAt]( [param:Vector3 normal], [param:Vector3 target] )

[page:Vector3 normal] - The normal vector (assumed to be unit length).
[page:Vector3 target] - The result vector.
Returns the irradiance (radiance convolved with cosine lobe) in the direction of the given normal.

### [method:this lerp]( [param:SphericalHarmonics3 sh], [param:Number alpha] )

[page:SphericalHarmonics3 sh] - The SH to interpolate with.
[page:Number alpha] - The alpha factor.
Linear interpolates between the given SH and this instance by the given alpha factor.

### [method:this scale]( [param:Number scale] )

[page:Number scale] - The scale factor.
Scales this SH by the given scale factor.

### [method:this set]( [param:Array coefficients] )

[page:Array coefficients] - An array of SH coefficients.
Sets the given SH coefficients to this instance.

### [method:Array toArray]( [param:Array array], [param:Number offset] )

[page:Array array] - (optional) The target array.
[page:Number offset] - (optional) The array offset.
Returns an array with the coefficients, or copies them into the provided array. The coefficients are represented as numbers.

### [method:this zero]()

Sets all SH coefficients to `0`.

## Static Methods

### [method:undefined getBasisAt]( [param:Vector3 normal], [param:Array shBasis] )

[page:Vector3 normal] - The normal vector (assumed to be unit length).
[page:Array shBasis] - The resulting SH basis.
Computes the SH basis for the given normal vector.

## Source

[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]