# [name]

Uniforms 是 GLSL 着色器中的全局变量。

## 代码示例

When declaring a uniform of a [page:ShaderMaterial], it is declared by value or by object.

`uniforms: { time: { value: 1.0 }, resolution: new Uniform( new Vector2() ) };`

## Uniform 种类

每个 Uniform 必须包括一个 *value* 属性。value 的类型必须和下表中 GLSL 的基本类型相对应。同样，Uniform 的结构体和队列 也是支持的。 GLSL基本类型队列必须要么被显示声明为一个 THREE 对象的队列，要么被声明为一个包含所有对象数据的队列。这就是说， 队列中的 GLSL 基础类型不能再是一个队列。举例，一个有 5 个 *vec2* 元素的队列，必须是一个包含 5 个 [page:Vector2] 的队列数组， 或包含 10 个 *number* 的队列。

Uniform 类型
GLSL 类型 | JavaScript 类型
--- | ---
int | [page:Number]
uint (WebGL 2) | [page:Number]
float | [page:Number]
bool | [page:Boolean]
bool | [page:Number]
vec2 | [page:Vector2 THREE.Vector2]
vec2 | [page:Float32Array Float32Array] (*)
vec2 | [page:Array Array] (*)
vec3 | [page:Vector3 THREE.Vector3]
vec3 | [page:Color THREE.Color]
vec3 | [page:Float32Array Float32Array] (*)
vec3 | [page:Array Array] (*)
vec4 | [page:Vector4 THREE.Vector4]
vec4 | [page:Quaternion THREE.Quaternion]
vec4 | [page:Float32Array Float32Array] (*)
vec4 | [page:Array Array] (*)
mat2 | [page:Float32Array Float32Array] (*)
mat2 | [page:Array Array] (*)
mat3 | [page:Matrix3 THREE.Matrix3]
mat3 | [page:Float32Array Float32Array] (*)
mat3 | [page:Array Array] (*)
mat4 | [page:Matrix4 THREE.Matrix4]
mat4 | [page:Float32Array Float32Array] (*)
mat4 | [page:Array Array] (*)
ivec2, bvec2 | [page:Float32Array Float32Array] (*)
ivec2, bvec2 | [page:Array Array] (*)
ivec3, bvec3 | [page:Int32Array Int32Array] (*)
ivec3, bvec3 | [page:Array Array] (*)
ivec4, bvec4 | [page:Int32Array Int32Array] (*)
ivec4, bvec4 | [page:Array Array] (*)
sampler2D | [page:Texture THREE.Texture]
samplerCube | [page:CubeTexture THREE.CubeTexture]

(*) 与最内层队列中 GSLS 的类型保持一致。包含队列中所有矢量的元素或矩阵中的元素。

## Structured Uniforms

Sometimes you want to organize uniforms as *structs* in your shader code. The following style must be used so *three.js* is able to process structured uniform data.

`uniforms = { data: { value: { position: new Vector3(), direction: new Vector3( 0, 0, 1 ) } } };` This definition can be mapped on the following GLSL code: `struct Data { vec3 position; vec3 direction; }; uniform Data data;`

## Structured Uniforms with Arrays

It's also possible to manage *structs* in arrays. The syntax for this use case looks like so:

`const entry1 = { position: new Vector3(), direction: new Vector3( 0, 0, 1 ) }; const entry2 = { position: new Vector3( 1, 1, 1 ), direction: new Vector3( 0, 1, 0 ) }; uniforms = { data: { value: [ entry1, entry2 ] } };` This definition can be mapped on the following GLSL code: `struct Data { vec3 position; vec3 direction; }; uniform Data data[ 2 ];`

## 构造函数

### [name]( [param:Object value] )

value -- 包含需要设置 Uniform 数据的对象。 数据类型必须是上述类型中的一种。

## 属性

### [property:Object value]

当前 uniform 的值。

## 方法

### [method:Uniform clone]()

返回该 Uniform 的克隆。
如果 Uniform 的 value 属性是一个带 clone() 方法的 [page:Object]，则克隆该对象时，value 的 clone() 方法也会被调用，否则克隆时只会使用赋值语句。 队列中的值会在该 Uniform 和 被克隆对象间共享。

## 源代码

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