# [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].

## Methods

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

[page:SphericalHarmonics3 sh] - The SH to add.

Adds the given SH to this instance.

### [method:SphericalHarmonics3 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:SphericalHarmonics3 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:SphericalHarmonics3 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:SphericalHarmonics3 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:SphericalHarmonics3 scale]( [param:Number scale] )

[page:Number scale] - The scale factor.

Scales this SH by the given scale factor.

### [method:SphericalHarmonics3 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:SphericalHarmonics3 zero]()

Sets all SH coefficients to 0.

## Static Methods

### [method:void 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]