ShaderLab: adding shader programs

In Unity, you usually write shaderA program that runs on the GPU. More info
See in Glossary programs in HLSL. To add HLSL code to your shader asset, you put the code inside a shader code block.

This page contains information about using shader code blocks. For information about writing HLSL itself, see Using HLSL in Unity.

Note: Unity also supports writing shader programs in other languages, although this is not generally needed or recommended. For more information, see Writing shaders.

Render pipeline compatibility

Types of shader code blocks

To add HLSL code, you can use the following types of shader code block:

• HLSLPROGRAM
• CGPROGRAM
• HLSLINCLUDE
• CGINCLUDE

To understand which to use when, you must understand both their prefix (HLSL or CG), and their suffix (PROGRAM or INCLUDE).

HLSL and CG prefixes

The difference between the blocks that begin with HLSL or CG is:

• The shader code blocks prefixed with CG are older. They include several of Unity’s built-in shader include files by default, which can be convenient if you need this functionality. The built-in includes are only compatible with the Built-in Render Pipeline.
• The shader code blocks prefixed with HLSL are newer. They do not include Unity’s built-in shader include files by default, so you must manually include any library code that you want to use. They are suitable for use with any render pipeline.

For information on Unity’s built-in shader include files, see Built-in shader include files.

PROGRAM and INCLUDE suffixes

The difference between the blocks that end with PROGRAM or INCLUDE is:

• The shader code blocks that end with PROGRAM are called shader program blocks. You use them to write shader programs. You write your HLSL shader code inside these blocks, and then place them inside a Pass block in your ShaderLabUnity’s language for defining the structure of Shader objects. More info
  See in Glossary code.
• The shader code blocks that end with INCLUDE are called shader include blocks. You use them to share common code between shader program blocks in the same source file. You write HLSL shader code that you want to share inside these blocks, and then place them inside a Pass, SubShader or Shader block in your ShaderLab code. It works in a similar way to using an include in your HLSL code.

Using a shader program block

Examples

Shader "Examples/ExampleShader"
{
    SubShader
    {
        Pass
        {                
              Name "ExamplePassName"
              Tags { "LightMode" = "ExampleLightModeTagValue" }

              // ShaderLab commands to set the render state go here

              HLSLPROGRAM
                // HLSL shader code goes here
              ENDHLSL
        }
    }
}

Using a shader include block

Examples

Shader "Examples/ExampleShader"
{
    SubShader
    {

        HLSLINCLUDE
            // HLSL code that you want to share goes here
        ENDHLSL

        Pass
        {                
              Name "ExampleFirstPassName"
              Tags { "LightMode" = "ExampleLightModeTagValue" }

              // ShaderLab commands to set the render state go here

              HLSLPROGRAM
                // This HLSL shader program automatically includes the contents of the HLSLINCLUDE block above
                // HLSL shader code goes here
              ENDHLSL
        }

        Pass
        {                
              Name "ExampleSecondPassName"
              Tags { "LightMode" = "ExampleLightModeTagValue" }

              // ShaderLab commands to set the render state go here

              HLSLPROGRAM
                // This HLSL shader program automatically includes the contents of the HLSLINCLUDE block above
                // HLSL shader code goes here
              ENDHLSL
        }

    }
}