Unity3D shader（3）——surface shader（二）

接着上篇，（仅仅作学习之用，不作技术参考，具体可以看unity3D官方例子）

1、立方体贴图的效果，这里的立方体贴图依据的是世界坐标。以下是一个最简单的立方体贴图的shader

Shader "Example/WorldRefl" { Properties { _MainTex ("Texture", 2D) = "white" {} _Cube ("Cubemap", CUBE) = "" {} } SubShader { Tags { "RenderType" = "Opaque" } CGPROGRAM #pragma surface surf Lambert struct Input { float2 uv_MainTex; float3 worldRefl; }; sampler2D _MainTex; samplerCUBE _Cube; void surf (Input IN, inout SurfaceOutput o) { o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb * 0.5; o.Emission = texCUBE (_Cube, IN.worldRefl).rgb; } ENDCG } Fallback "Diffuse" }

2、如果你想立方体呈现法线贴图的效果，那么首先需要把INTERNAL_DATA加入到input结构中。最后还需要用WorldReflectionVector将法向量转换一下。从最后的效果来看，使立方体贴图增加了法线贴图的效果。

Shader "Example/WorldRefl Normalmap" { Properties { _MainTex ("Texture", 2D) = "white" {} _BumpMap ("Bumpmap", 2D) = "bump" {} _Cube ("Cubemap", CUBE) = "" {} } SubShader { Tags { "RenderType" = "Opaque" } CGPROGRAM #pragma surface surf Lambert struct Input { float2 uv_MainTex; float2 uv_BumpMap; float3 worldRefl; INTERNAL_DATA }; sampler2D _MainTex; sampler2D _BumpMap; samplerCUBE _Cube; void surf (Input IN, inout SurfaceOutput o) { o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb * 0.5; o.Normal = UnpackNormal (tex2D (_BumpMap, IN.uv_BumpMap)); o.Emission = texCUBE (_Cube, WorldReflectionVector (IN, o.Normal)).rgb; } ENDCG } Fallback "Diffuse" }

3、减去部分视图

Shader "Example/Slices" { Properties { _MainTex ("Texture", 2D) = "white" {} _BumpMap ("Bumpmap", 2D) = "bump" {} } SubShader { Tags { "RenderType" = "Opaque" } Cull Off CGPROGRAM #pragma surface surf Lambert struct Input { float2 uv_MainTex; float2 uv_BumpMap; float3 worldPos; }; sampler2D _MainTex; sampler2D _BumpMap; void surf (Input IN, inout SurfaceOutput o) { clip (frac((IN.worldPos.y+IN.worldPos.z*0.1) * 5) - 0.5); o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb; o.Normal = UnpackNormal (tex2D (_BumpMap, IN.uv_BumpMap)); } ENDCG } Fallback "Diffuse" }

4、沿着法线方向增加一定的厚度，很经典的应用是增加雪的厚度

Shader "Example/Normal Extrusion" { Properties { _MainTex ("Texture", 2D) = "white" {} _Amount ("Extrusion Amount", Range(-1,1)) = 0.5 } SubShader { Tags { "RenderType" = "Opaque" } CGPROGRAM #pragma surface surf Lambert vertex:vert struct Input { float2 uv_MainTex; }; float _Amount; void vert (inout appdata_full v) { v.vertex.xyz += v.normal * _Amount; } sampler2D _MainTex; void surf (Input IN, inout SurfaceOutput o) { o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb; } ENDCG } Fallback "Diffuse" }

5、对每个像素进行计算，这样可以使每个面呈现不一样的效果，从而减少贴图的数量

Shader "Example/Custom Vertex Data" { Properties { _MainTex ("Texture", 2D) = "white" {} } SubShader { Tags { "RenderType" = "Opaque" } CGPROGRAM #pragma surface surf Lambert vertex:vert struct Input { float2 uv_MainTex; float3 customColor; }; void vert (inout appdata_full v, out Input o) { UNITY_INITIALIZE_OUTPUT(Input,o); o.customColor = abs(v.normal); } sampler2D _MainTex; void surf (Input IN, inout SurfaceOutput o) { o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb; o.Albedo *= IN.customColor; } ENDCG } Fallback "Diffuse" }

6、让立方体的面的颜色随自己控制

Shader "Example/Tint Final Color" { Properties { _MainTex ("Texture", 2D) = "white" {} _ColorTint ("Tint", Color) = (1.0, 0.6, 0.6, 1.0) } SubShader { Tags { "RenderType" = "Opaque" } CGPROGRAM #pragma surface surf Lambert finalcolor:mycolor struct Input { float2 uv_MainTex; }; fixed4 _ColorTint; void mycolor (Input IN, SurfaceOutput o, inout fixed4 color) { color *= _ColorTint; } sampler2D _MainTex; void surf (Input IN, inout SurfaceOutput o) { o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb; } ENDCG } Fallback "Diffuse" }