Important: The Built-In Render Pipeline is deprecated and will be made obsolete in a future release.
It remains supported, including bug fixes and maintenance, through the full Unity 6.7 LTS lifecycle.
For more information on migration, refer to Migrating from the Built-In Render Pipeline to the Universal Render Pipeline and Render pipeline feature comparison.
surfaceFunction - which Cg function has surface shader code. The function should have the form of void surf (Input IN, inout SurfaceOutput o), where Input is a structure you have defined. Input should contain any texture coordinates and extra automatic variables needed by surface function.lightModel - lighting model to use. Built-in ones are physically based Standard and StandardSpecular, as well as simple non-physically based Lambert (diffuse) and BlinnPhong (specular). See Custom Lighting Models page for how to write your own.
Standard lighting model uses SurfaceOutputStandard output struct, and matches the Standard (metallic workflow) shader in Unity.StandardSpecular lighting model uses SurfaceOutputStandardSpecular output struct, and matches the Standard (specular setup) shader in Unity.Lambert and BlinnPhong lighting models are not physically based (coming from Unity 4.x), but the shaders using them can be faster to render on low-end hardware.