A tiny and flexible "surface shader" solution for Unity URP. A more ideal solution here: https://github.com/slipster216/UnityModularShaderPrototype

Since URP doesn't support surface shader anymore, if shader graph alone can't fulfill all your needs and writing raw vert/frag lit shader supporting all light & shadow in URP is just too much work, try download this project, and start writing your own "surface shader" in URP.

"Surface shader" makes shader development much easier and faster in URP, because user don't need to know/learn/write lighting related concrete code at all. User only need to write the surface function, then select a good looking lighting function(edit 1 line of code in shader), that's all the work to produce a lit shader.

left sphere = our "surface shader" with:

• vertex animation
• added an extra custom pass (this image's "surface shader" used that extra custom pass as an outline pass)
• selectable lighting method (this image's "surface shader" selected a cel shade PBR lighting method)
• local postprocess
• auto support DepthOnly and ShadowCaster pass

right sphere = default URP PBR lit shader

• "surface shader" is still a regular .shader file, can compile normally
• SRP batcher compatible
• can do everything shader graph can do, but 100% in code, version control friendly!
• can add extra custom pass (e.g. outline pass)
• can switch to any lighting function just by editing 1 line of code
• support using your own lighting function .hlsl
• can apply any additional local postprocess
• everything are just regular .shader/.hlsl files, no C#

struct UserGeometryOutputData
{
    float3 positionOS;
    float3 normalOS;
    float4 tangentOS;
};

struct UserSurfaceOutputData
{
    half3   albedo;             
    half3   normalTS;          
    half3   emission;     
    half    metallic;
    half    smoothness;
    half    occlusion;                
    half    alpha;          
    half    alphaClipThreshold;
};

• selectable lighting function .hlsl (you can pick PBR lit, PBR lit cel shade, or your own lighting function .hlsl)
• local postprocess method (e.g. you can still add more color edit logic after lighting has finished)

1. only clone Assets/NiloCat/NiloURPSurfaceShader folder into your URP project
2. In your project, open NiloURPSurfaceShader_Example.shader, edit the following according to your need:

• UserGeometryDataOutputFunction(...)
• UserSurfaceDataOutputFunction(...)
• FinalPostProcessFrag(...)
• #include "../LightingFunctionLibrary/XXXLightingFunction.hlsl" 3)If you want to create your own "surface shader", clone a copy of NiloURPSurfaceShader_Example.shader before edit it, it is easier.

It is a very early WIP project and will change a lot, but I need to finish this in order to build more complex toon shaders on top of this project. This project will be pure .shader/.hlsl, to see how far we can reach without C# codegen. If you are interested in this "surface shader" concept, you can clone it, try writing your own surface shader functions, see if the current "surface shader" design can fulfill your shader development needs.

You can send me suggestions/bug report, or open discussion/just chat in Issues tab, or even send pull requests are very welcome!

• URP 7.3.1 or above
• Unity 2019.4 LTS or above