HLSL in Unity

In Unity, you use the HLSL programming language to write shaderA program that runs on the GPU. More info
See in Glossary programs.

This section of the manual includes information on using HLSL in a Unity-specific way. For general information on writing HLSL, see Microsoft’s HLSL documentation.

Note: Unity originally used the Cg language, hence the name of some of Unity’s keywords (CGPROGRAM) and file extensions (.cginc). Unity no longer uses Cg, but these names are still in use.

Adding HLSL code to your ShaderLab code

You place your HLSL code inside code blocks in your ShaderLabUnity’s language for defining the structure of Shader objects. More info
See in Glossary code. They usually look like this:

  Pass {
      // ... the usual pass state setup ...
      
      HLSLPROGRAM
      // compilation directives for this snippet, e.g.:
      #pragma vertex vert
      #pragma fragment frag
      
      // the shader program itself
      
      ENDHLSL

      // ... the rest of pass ...
  }

For more information on shader code blocks, see ShaderLab: adding shader programs.

HLSL syntax

HLSL has two syntaxes: a legacy DirectX 9-style syntax, and a more modern DirectX 10+ style syntax. The difference is mostly in how texture sampling functions work:

• The legacy syntax uses sampler2D, tex2D() and similar functions. This syntax works on all platforms.
• The DX10+ syntax uses Texture2D, SamplerState and .Sample() functions. Some forms of this syntax do not work on OpenGL platforms, because textures and samplers are not different objects in OpenGL.

Unity provides shader libraries that contain preprocessor macros to help you manage these differences. For more information, see Built-in shader macros.