Vertex Modifier of Surface Shader

【Vertex Modifier of Surface Shader】

　　Surface shader compilation directive vertex:functionName  可以用于指定顶点着色器。A function that takes inout appdata_full parameter.

　　Surface shader中顶点函数传出的坐标必须是Local坐标。在Vert执行完毕后，Surface shader会自动将此Local坐标乘以MVP矩阵。

 1 Shader "Example/Normal Extrusion" {

 2     Properties {

 3       _MainTex ("Texture", 2D) = "white" {}

 4       _Amount ("Extrusion Amount", Range(-1,1)) = 0.5

 5     }

 6     SubShader {

 7       Tags { "RenderType" = "Opaque" }

 8       CGPROGRAM

 9       #pragma surface surf Lambert vertex:vert

10       struct Input {

11           float2 uv_MainTex;

12       };

13       float _Amount;

14       void vert (inout appdata_full v) {

15           v.vertex.xyz += v.normal * _Amount;

16       }

17       sampler2D _MainTex;

18       void surf (Input IN, inout SurfaceOutput o) {

19           o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;

20       }

21       ENDCG

22     } 

23     Fallback "Diffuse"

24   }

　　

　　如果想传递给surface自定义数据（per-pixel），顶点函数需要添加out Input 参数如下：

 1   Shader "Example/Custom Vertex Data" {

 2     Properties {

 3       _MainTex ("Texture", 2D) = "white" {}

 4     }

 5     SubShader {

 6       Tags { "RenderType" = "Opaque" }

 7       CGPROGRAM

 8       #pragma surface surf Lambert vertex:vert

 9       struct Input {

10           float2 uv_MainTex;

11           float3 customColor;

12       };

13       void vert (inout appdata_full v, out Input o) {

14           UNITY_INITIALIZE_OUTPUT(Input,o);

15           o.customColor = abs(v.normal);

16       }

17       sampler2D _MainTex;

18       void surf (Input IN, inout SurfaceOutput o) {

19           o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;

20           o.Albedo *= IN.customColor;

21       }

22       ENDCG

23     } 

24     Fallback "Diffuse"

25   }

　　

参考：file:///C:/Program%20Files%20(x86)/Unity/Editor/Data/Documentation/html/en/Manual/SL-SurfaceShaderExamples.html