Unity3D Shader 使指定颜色过滤成透明

该Shader能够实现以下效果： 

绿板过滤，将视频的某颜色过滤成透明，甚至你们可以以该代码为前提去实现各种颜色方面的效果实现。

Shader "MyShader/FilterfColor" { 
    Properties { 
        _MainTex ("Base (RGB)", 2D) = "white" {} 
        _FilterfColor("Ridof (RGB)",Color)=(1,1,1,1) 
    } 
    SubShader { 
        Tags { "RenderType"="Opaque" } 
        Blend SrcAlpha OneMinusSrcAlpha 
        pass 
        { 
            CGPROGRAM 

            #pragma vertex vertext_convert
            #pragma fragment fragment_convert
            #include "UnityCG.cginc" 

            sampler2D  _MainTex; 
            sampler2D  _MainTex1; 
            float4  _FilterfColor; 
            struct Inputvrite 
            { 
                float4 vertex : POSITION; 
                float4 texcoord : TEXCOORD0; 
            }; 
            struct Inputfragment 
            { 
                float4 pos : SV_POSITION; 
                float4 uv : TEXCOORD0; 
            }; 

            float ColorLerp(float3 tmp_nowcolor,float3 tmp_FilterfColor) 
            { 
                float3 dis = float3(abs(tmp_nowcolor.x - tmp_FilterfColor.x),abs(tmp_nowcolor.y - tmp_FilterfColor.y),abs(tmp_nowcolor.z - tmp_FilterfColor.z)); 
                float dis0 =sqrt(pow(dis.x,2)+pow(dis.y,2)+pow(dis.z,2)); 
                float maxdis = sqrt(3); 
                float dis1 = lerp(0,maxdis,dis0); 
                return dis1; 
            } 

            Inputfragment vertext_convert(Inputvrite i) 
            { 
                Inputfragment o; 
                o.pos = mul(UNITY_MATRIX_MVP,i.vertex); 
                o.uv = float4(i.texcoord.xy,1,1); 
                return o; 
            } 

            float4 fragment_convert(Inputfragment o) : COLOR 
            { 
                float4 c = tex2D(_MainTex,o.uv); 
                c.a *=ColorLerp(c.rgb,_FilterfColor.rgb); 
                return c; 
            } 


        ENDCG 
        } 
    } 
    FallBack "Diffuse"  

}