ShaderLab: defining material properties

This page contains information on using a Properties block in your ShaderLabUnity’s language for defining the structure of Shader objects. More info
See in Glossary code to define material properties for a Shader objectAn instance of the Shader class, a Shader object is container for shader programs and GPU instructions, and information that tells Unity how to use them. Use them with materials to determine the appearance of your scene. More info
See in Glossary.

Overview

In your ShaderLab code, you can define material properties. A material property is a property that Unity stores as part of the material asset. This allows artists to create, edit and share materials with different configurations.

If you use material properties:

• You can get or set the value of a variable in a ShaderA program that runs on the GPU. More info
  See in Glossary object by calling functions on the material (such as Material.SetFloat).
• You can view and edit the values using the material InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
  See in Glossary.
• Unity saves the changes that you make as part of the material asset, so they persist between sessions.

If you do not use material properties: * You can still get or set the value of a variable in a Shader object by calling a function on a material. * There is no visual editor for these values. * Changes do not persist between sessions.

The only times that you would normally not create a material property is if you want to set shader property values entirely using scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
See in Glossary (for example, if you are making procedural content), if the properties cannot be made into material properties, or if you don’t want them to be edited in the Inspector.

Render pipeline compatibility

Using the Properties block

To assign material properties to a Shader object in ShaderLab, you place a Properties block inside a Shader block.

Material property declarations

All material property declarations follow this basic format:

[optional: attribute] name("display text in Inspector", type name) = default value

The exact syntax varies by type.

This section contains information on:

• Material property declaration syntax by type.
• Material property attributes

Material property declaration syntax by type

The type name and the syntax for the default value depend on the type of the property.

In shader code, it is conventional to begin all property names with an underscore character. The examples on this page follow this convention.

Material property attributes

Material property declarations can have an optional attribute that tells Unity how to handle them.

In addition to the attributes listed here, you can use the same syntax to add a MaterialPropertyDrawer to a material property. These let you control how material properties appear in the Inspector window.

Using material properties with C# code

Material properties are represented in C# code by the MaterialProperty class.

To access variables defined in your HLSL code, you can call Material.GetFloat, Material.SetFloat. There are other, similar methods; see the Material API documentation for a full list. When you access HLSL variables using these APIs, it doesn’t matter whether the variable is a material property or not.

In the Unity Editor, you can control how material properties appear in the Inspector window. The easiest way to do this is using a MaterialPropertyDrawer. For more complex needs, you can use the MaterialEditor, MaterialProperty, and ShaderGUI classes. For more information on creating custom GUIs for shaders, see ShaderLab:assigning a custom editor.

Using material properties to set variables in ShaderLab code

To set the value of a variable in your ShaderLab code from a material property, put the material property name in square brackets in your ShaderLab code.

This example code demonstrates the syntax for using a material property to set the units value of the ShaderLab Offset command.

Shader "Examples/MaterialPropertyShaderLab"
{
    Properties
    {
        // Change this value in the Material Inspector to affect the value of the Offset command
        _OffsetUnitScale ("Offset unit scale", Integer) = 1
    }
    SubShader
    {
        // The code that defines the rest of the SubShader goes here

        Pass
        {
            Offset 0, [_OffsetUnitScale]

           // The code that defines the rest of the Pass goes here
        }
    }
}

Using material properties to set variables in HLSL code

To set the value of a variable in HLSL code using a material property, give the material property the same name as the shader property.

You can see this technique in the following articles, which include working code examples:

• Writing vertex and fragment shaders for the Built-in Render Pipeline
• Writing custom shaders for the Universal Render Pipeline