Built-in shader include files

Unity contains several files that can be used by your shader programs to bring in predefined variables and helper functions. This is done by the standard #include directive, e.g.:

CGPROGRAM
// ...
#include "UnityCG.cginc"
// ...
ENDCG

Shader include files in Unity are with .cginc extension, and the built-in ones are:

• HLSLSupport.cginc - (automatically included) Helper macros and definitions for cross-platform shaderA program that runs on the GPU. More info
  See in Glossary compilation.
• UnityShaderVariables.cginc - (automatically included) Commonly used global variables.
• UnityCG.cginc - commonly used helper functions.
• AutoLight.cginc - lighting & shadowing functionality, e.g. surface shadersA streamlined way of writing shaders for the Built-in Render Pipeline. More info
  See in Glossary use this file internally.
• Lighting.cginc - standard surface shader lighting models; automatically included when you’re writing surface shaders.
• TerrainEngine.cginc - helper functions for TerrainThe landscape in your scene. A Terrain GameObject adds a large flat plane to your scene and you can use the Terrain’s Inspector window to create a detailed landscape. More info
  See in Glossary & Vegetation shaders.

These files are found inside Unity application ({unity install path}/Data/CGIncludes/UnityCG.cginc on Windows, /Applications/Unity/Unity.app/Contents/CGIncludes/UnityCG.cginc on Mac), if you want to take a look at what exactly is done in any of the helper code.

HLSLSupport.cginc

This file is automatically included when compiling CGPROGRAM shaders (but not included for HLSLPROGRAM ones). It declares various preprocessor macros to aid in multi-platform shader development.

UnityShaderVariables.cginc

This file is automatically included when compiling CGPROGRAM shaders (but not included for HLSLPROGRAM ones). It declares various built-in global variables that are commonly used in shaders.

UnityCG.cginc

This file is often included in 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. It declares many built-in helper functions and data structures.

Data structures in UnityCG.cginc

• struct appdata_base: vertex shaderA program that runs on each vertex of a 3D model when the model is being rendered. More info
  See in Glossary input with position, normal, one texture coordinate.
• struct appdata_tan: vertex shader input with position, normal, tangent, one texture coordinate.
• struct appdata_full: vertex shader input with position, normal, tangent, vertex color and two texture coordinates.
• struct appdata_img: vertex shader input with position and one texture coordinate.