Uniform - Verge3D User Manual - Soft8Soft
Description: Learn how to use Uniform in your interactive 3D apps made with Verge3D

# Uniform

Uniforms are global GLSL variables. They are passed to shader programs.

## Code Example

When declaring a uniform of a ShaderMaterial, it is declared by value or by object.

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

## Uniform types

Each uniform must have a `value` property. The type of the value must correspond to the type of the uniform variable in the GLSL code as specified for the primitive GLSL types in the table below. Uniform structures and arrays are also supported. GLSL arrays of primitive type must either be specified as an array of the corresponding v3d objects or as a flat array containing the data of all the objects. In other words; GLSL primitives in arrays must not be represented by arrays. This rule does not apply transitively. An array of `vec2` arrays, each with a length of five vectors, must be an array of arrays, of either five Vector2 objects or ten `number`s.

Uniform types
GLSL type | JavaScript type
--- | ---
int | Integer
uint (WebGL 2) | Integer
float | Float
bool | Boolean
bool | Integer
vec2 | v3d.Vector2
vec2 | Float32Array (*)
vec2 | Array (*)
vec3 | v3d.Vector3
vec3 | v3d.Color
vec3 | Float32Array (*)
vec3 | Array (*)
vec4 | v3d.Vector4
vec4 | v3d.Quaternion
vec4 | Float32Array (*)
vec4 | Array (*)
mat2 | Float32Array (*)
mat2 | Array (*)
mat3 | v3d.Matrix3
mat3 | Float32Array (*)
mat3 | Array (*)
mat4 | v3d.Matrix4
mat4 | Float32Array (*)
mat4 | Array (*)
ivec2, bvec2 | Float32Array (*)
ivec2, bvec2 | Array (*)
ivec3, bvec3 | Int32Array (*)
ivec3, bvec3 | Array (*)
ivec4, bvec4 | Int32Array (*)
ivec4, bvec4 | Array (*)
sampler2D | v3d.Texture
samplerCube | v3d.CubeTexture

(*) Same for an (innermost) array (dimension) of the same GLSL type, containing the components of all vectors or matrices in the array.

## Structured Uniforms

Sometimes you want to organize uniforms as `structs` in your shader code. The following style must be used so Verge3D 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];`

## Constructor

### Uniform(value : Object)

value — An object containing the value to set up the uniform. It's type must be one of the Uniform Types described above.

## Properties

### # .value : Object

Current value of the uniform.

## Methods

### # .clone() → Uniform

Returns a clone of this uniform. If the uniform's value property is an Object with a clone() method, this is used, otherwise the value is copied by assignment. Array values are shared between cloned Uniforms.

## Source

For more info on how to obtain the source code of this module see this page.