ShaderLab: defining a Pass

To define a Pass in ShaderLabUnity’s language for defining the structure of Shader objects. More info
See in Glossary, use a Pass block. This page contains information on using Pass 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 objectsAn 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, SubShaders and Passes, see Shader object fundamentals.

Overview

A Pass is the fundamental element of a Shader object. It contains instructions for setting the state of the GPU, and the shader programs that run on the GPU.

Simple Shader objects might contain only a single Pass, but more complex shaders can contain multiple Passes. You can use separate Passes to define parts of your Shader object that work differently; for example, parts that require a change to the render state, different shader programs, or a different LightMode Pass tag.

Note: In render pipelines based on the Scriptable Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info
See in Glossary, you can use a RenderStateBlock to change the render state on the GPU, without requiring a separate Pass.

Render pipeline compatibility

Using the Pass block

To define a regular Pass in ShaderLab, you place a Pass block inside a SubShader block.

Inside the Pass block, you can:

• Assign a name to the Pass, using a Name block. See ShaderLab: assigning a name to a Pass.
• Assign key-value pairs of data to the Pass, using a Tags block. See ShaderLab: assigning tags to a Pass.
• Perform operations using ShaderLab commands. See ShaderLab: using commands.
• Add shader code to the Pass, using a shader code block. See ShaderLab: shader code blocks.
• Specify package requirements using the PackageRequirements block. This makes Unity only run the Pass if the required packages are installed. See ShaderLab: specifying package requirements.

You can also define two special types of Pass, using the UsePass or GrabPass commands. For information on those commands, see ShaderLab commands: UsePass or ShaderLab commands: GrabPass.

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
    {
        Pass
        {                
              Name "ExamplePassName"
              Tags { "ExampleTagKey" = "ExampleTagValue" }

              // ShaderLab commands go here.

              // HLSL code goes here.
        }
    }
}