ShaderLab: defining a SubShader

To define a SubShader in ShaderLabUnity’s language for defining the structure of Shader objects. More info
See in Glossary, you use a SubShader block. This page contains information on using SubShader blocks.

For information on how a ShaderA program that runs on the GPU. More info
See in Glossary object works, and the relationship between Shader objects, SubShaders and Passes, see Shader objects introduction.

Overview

A Shader object contains one or more SubShaders. SubShaders let you define different GPU settings and shader programs for different hardware, render pipelines, and runtime settings. Some Shader objects contain only a single SubShader; others contain multiple SubShaders to support a range of different configurations.

Render pipeline compatibility

Feature name	Built-in Render Pipeline	Universal Render Pipeline (URP)	High Definition Render Pipeline (HDRP)	Custom SRP
ShaderLab: SubShader block	Yes	Yes	Yes	Yes

Using the SubShader block

In ShaderLab, you define a SubShader by placing a SubShader block inside a Shader block.

Inside the SubShader block, you can:

Assign a LODThe Level Of Detail (LOD) technique is an optimization that reduces the number of triangles that Unity has to render for a GameObject when its distance from the Camera increases. More info
See in Glossary (level of detail) value to the SubShader, using the LOD block. See assigning a LOD value to a SubShader.
Assign key-value pairs of data to the SubShader, using the Tags block. See ShaderLab: assigning tags to a SubShader.
Add GPU instructions or shader code to the SubShader, using ShaderLab commands. See ShaderLab: using commands.
Define one or more Passes, using the Pass block. See ShaderLab: defining a Pass.

Signature	Function
`SubShader` `{` `<optional: LOD>` `<optional: tags>` `<optional: commands>` `<One or more Pass definitions>` `}`	Defines a SubShader. You can define as many Passes as you like within a SubShader.

Examples

This example code demonstrates the syntax for creating a Shader object that contains a single SubShader, which in turn contains a single Pass.

Shader "Examples/SinglePass"
{
    SubShader
    {
        Tags { "ExampleSubShaderTagKey" = "ExampleSubShaderTagValue" }
        LOD 100

         // ShaderLab commands that apply to the whole SubShader go here. 

        Pass
        {                
              Name "ExamplePassName"
              Tags { "ExamplePassTagKey" = "ExamplePassTagValue" }

              // ShaderLab commands that apply to this Pass go here.

              // HLSL code goes here.
        }
    }
}

ShaderLab: assigning a custom editor

ShaderLab: assigning tags to a SubShader