Parameter QML Type | Qt 3D 5.12.10

- Qt 5.12
- Qt 3D
- QML Types
- Parameter QML Type
- Qt 5.12.10 Reference Documentation

# Parameter QML Type

Provides storage for a name and value pair. This maps to a shader uniform. More...

Import Statement: | import Qt3D.Render 2.12
Instantiates: | QParameter

- List of all members, including inherited members

## Properties

- name : QString
- value : QVariant

## Detailed Description

A Parameter can be referenced by a RenderPass, Technique, Effect, Material, TechniqueFilter, RenderPassFilter. At runtime, depending on which shader is selected for a given step of the rendering, the value contained in a Parameter will be converted and uploaded if the shader contains a uniform with a name matching that of the Parameter.

     Parameter {
         name: "diffuseColor"
         value: "blue"
     }

     // Works with the following GLSL uniform shader declarations
     // uniform vec4 diffuseColor;
     // uniform vec3 diffuseColor;
     // uniform vec2 diffuseColor;
     // uniform float diffuseColor;

Note: some care must be taken to ensure the value wrapped by a Parameter can actually be converted to what the real uniform expect. Giving a value stored as an int where the actual shader uniform is of type float could result in undefined behaviors.

Note: when the targeted uniform is an array, the name should be the name of the uniform with [0] appended to it.

     Parameter {
         name: "diffuseValues[0]"
         value: [0.0, 1.0. 2.0, 3.0, 4.0, 883.0, 1340.0, 1584.0]
     }

     // Matching GLSL shader uniform  declaration
     // uniform float diffuseValues[8];

When it comes to texture support, the Parameter value should be set to the appropriate texture subclass that matches the sampler type of the shader uniform.

     Parameter {
         name: "diffuseTexture"
         value: Texture2D { ... }
     }

     // Works with the following GLSL uniform shader declaration
     // uniform sampler2D diffuseTexture

See also Qt3DRender::QAbstractTexture.

## Property Documentation

name : QString

Specifies the name of the parameter

value : QVariant

Specifies the value of the parameter