1 summary

CGInclude file , The suffix is .cginc The file of , As the name suggests, it is CG Include files for , It's kind of like C/C++ The header file , We can use some commonly used macros 、 Structure 、 Global variables 、 Help functions are written in CGInclude In file , For efficient reuse .

2 Unity Of CGInclude file

Unity I also have many CGInclude file , Located in the installation directory Editor/Data/CGIncludes Catalog （Windows edition ）, As shown below . We are writing by ourselves shader It is often used when Unity Of these CG Include files , such as UnityCG.cginc Various structures defined in ,Lighting.cginc Various lighting models in .

3 Write our own CGInclude file

The standard CGInlcude The file structure is as follows ：
MyCG.cginc

#ifndef XXX
#define XXX

// Here we define common macros 、 Structure 、 Global variables 、 Help functions, etc 

e.g.

#ifndef MY_CG_INCLUDE
#define MY_CG_INCLUDE

……

#endif

Use #ifndef、#define、#endif To avoid repeated definitions , Because it may be carried out in many places #include "MyCG.cginc" operation , Without this judgment, there will be repeated definitions ,#ifndef XXX It means if the definition does not XXX, Before executing the next code , Otherwise, just skip

inline Inline function

We are Unity The built-in CGInclude Many functions can be found in the file inline keyword , Yes inline The modified function is an inline function , It can solve the problem that some frequently called small functions consume a lot of stack space （ Stack memory ） The problem of , but inline There are limits to the use of ,inline It is only suitable for functions with simple code in the function body and will be used when they are called frequently , Cannot contain complex structure control statements such as while、switch, And the inline function itself cannot be a direct recursive function （ namely , I also call my own functions inside ）.

4 Use our own CGInclude file

contain CGInclude file
If used shader and CGInclude The files are in the same directory , Can directly include
.shader

CGPROGRAM

#include "MyCG.cginc"

ENDCG

If not in a directory , You need to add relative paths , such as CGInclude The file in shader In the directory above the file , Then for
#include “…/MyCG.cginc”
there “…/“ Represents the directory above , Two level catalog , Then use ”…/…/”, And so on
If in shader File directory CGInclude In the folder , Then for
#include “CGInclude/MyCG.cginc”

Use caution

contain CGInclude After the document , We can directly use various macros in the file 、 Structure 、 Variable 、 Help function, etc .
But one thing to pay special attention to is , If we were CGInclude Define some variables that need external assignment , We need to remember in shader Assign or declare as Property assignment

Reference resources

《 Use CgInclude Let your Shader modularization ——Unity Built in CgInclude file 》
https://blog.csdn.net/candycat1992/article/details/38780387
《 Use CgInclude Let your Shader modularization —— establish CgInclude File storage lighting model 》
https://blog.csdn.net/candycat1992/article/details/38920347
《 Use CgInclude Let your Shader modularization —— Use #define Instruction creation Shader》
https://blog.csdn.net/candycat1992/article/details/38961411