Unity3D双面渲染

那个其实黑简单，只要把背面剔除关了就可以了，官网有标准shader的实现，然后改下就可以了。

这里只改alpha测试的shader，如果要改alpha混合的shader类似。

内建shader路径是Transparent/Cutout/VertexLit和Transparent/Cutout/Diffuse，两个里面在pass里面把Cull Off加起就可以了，然后shader的路径名要改下，不然会覆盖掉内建shader。

另外我遇到的一点问题是，Diffuse那个shader在pc上是正常的，在手机上不正常，VertexList在手机上是正常的。

这个跟硬件有关系，不过好在u3d的shader对硬件平台的处理上还可以比较方便。

在使用的时候那种需要渲染背面的和不需要渲染背面的要分材质，不然效率有影响。

 

附上改过后的shader：

AlphaTest.shader

Shader "Custom/AlphaTest" {Properties {_Color ("Main Color", Color) = (1,1,1,1)_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}_Cutoff ("Alpha cutoff", Range(0,1)) = 0.5}SubShader {Pass{Cull Off}Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}LOD 200CGPROGRAM#pragma surface surf Lambert alphatest:_Cutoffsampler2D _MainTex;fixed4 _Color;struct Input {float2 uv_MainTex;};void surf (Input IN, inout SurfaceOutput o) {fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;o.Albedo = c.rgb;o.Alpha = c.a;}ENDCG}FallBack "Custom/AlphaVerList"}

 

AlphaVerList.shader

Shader "Custom/AlphaVerList" {Properties {_Color ("Main Color", Color) = (1,1,1,1)_SpecColor ("Spec Color", Color) = (1,1,1,0)_Emission ("Emissive Color", Color) = (0,0,0,0)_Shininess ("Shininess", Range (0.1, 1)) = 0.7_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}_Cutoff ("Alpha cutoff", Range(0,1)) = 0.5}// 2/3 texture stage GPUsSubShader {Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}LOD 100// Non-lightmappedPass {Tags { "LightMode" = "Vertex" }Alphatest Greater [_Cutoff]AlphaToMask TrueColorMask RGBMaterial {Diffuse [_Color]Ambient [_Color]Shininess [_Shininess]Specular [_SpecColor]Emission [_Emission]}Cull OffLighting OnSeparateSpecular OnSetTexture [_MainTex] {Combine texture * primary DOUBLE, texture * primary } }// Lightmapped, encoded as dLDRPass {Tags { "LightMode" = "VertexLM" }Alphatest Greater [_Cutoff]AlphaToMask TrueColorMask RGBCull OffBindChannels {Bind "Vertex", vertexBind "normal", normalBind "texcoord1", texcoord0 // lightmap uses 2nd uvBind "texcoord", texcoord1 // main uses 1st uv}SetTexture [unity_Lightmap] {matrix [unity_LightmapMatrix]constantColor [_Color]combine texture * constant}SetTexture [_MainTex] {combine texture * previous DOUBLE, texture * primary}}// Lightmapped, encoded as RGBMPass {Tags { "LightMode" = "VertexLMRGBM" }Alphatest Greater [_Cutoff]AlphaToMask TrueColorMask RGBCull OffBindChannels {Bind "Vertex", vertexBind "normal", normalBind "texcoord1", texcoord0 // lightmap uses 2nd uvBind "texcoord1", texcoord1 // unusedBind "texcoord", texcoord2 // main uses 1st uv}SetTexture [unity_Lightmap] {matrix [unity_LightmapMatrix]combine texture * texture alpha DOUBLE}SetTexture [unity_Lightmap] {constantColor [_Color]combine previous * constant}SetTexture [_MainTex] {combine texture * previous QUAD, texture * primary}}// Pass to render object as a shadow casterPass {Name "Caster"Tags { "LightMode" = "ShadowCaster" }Offset 1, 1Cull OffFog {Mode Off}ZWrite On ZTest LEqual Cull OffCGPROGRAM#pragma vertex vert#pragma fragment frag#pragma multi_compile_shadowcaster#pragma fragmentoption ARB_precision_hint_fastest#include "UnityCG.cginc"struct v2f { V2F_SHADOW_CASTER;float2  uv : TEXCOORD1;};uniform float4 _MainTex_ST;v2f vert( appdata_base v ){v2f o;TRANSFER_SHADOW_CASTER(o)o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);return o;}uniform sampler2D _MainTex;uniform fixed _Cutoff;uniform fixed4 _Color;float4 frag( v2f i ) : COLOR{fixed4 texcol = tex2D( _MainTex, i.uv );clip( texcol.a*_Color.a - _Cutoff );SHADOW_CASTER_FRAGMENT(i)}ENDCG}// Pass to render object as a shadow collectorPass {Name "ShadowCollector"Tags { "LightMode" = "ShadowCollector" }Cull OffFog {Mode Off}ZWrite On ZTest LEqualCGPROGRAM#pragma vertex vert#pragma fragment frag#pragma fragmentoption ARB_precision_hint_fastest#pragma multi_compile_shadowcollector#define SHADOW_COLLECTOR_PASS#include "UnityCG.cginc"struct v2f {V2F_SHADOW_COLLECTOR;float2  uv : TEXCOORD5;};uniform float4 _MainTex_ST;v2f vert (appdata_base v){v2f o;TRANSFER_SHADOW_COLLECTOR(o)o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);return o;}uniform sampler2D _MainTex;uniform fixed _Cutoff;uniform fixed4 _Color;fixed4 frag (v2f i) : COLOR{fixed4 texcol = tex2D( _MainTex, i.uv );clip( texcol.a*_Color.a - _Cutoff );SHADOW_COLLECTOR_FRAGMENT(i)}ENDCG}}// 1 texture stage GPUsSubShader {Tags {"IgnoreProjector"="True" "RenderType"="TransparentCutout"}LOD 100Pass {Tags { "LightMode" = "Always" }Alphatest Greater [_Cutoff]AlphaToMask TrueColorMask RGBMaterial {Diffuse [_Color]Ambient [_Color]Shininess [_Shininess]Specular [_SpecColor]Emission [_Emission]}Cull OffLighting OnSeparateSpecular OnSetTexture [_MainTex] {Combine texture * primary DOUBLE, texture * primary }}}}