（新增5.3版本的需求）最近美术同事要求：我们要能给够水和云这样的半透明场景特效上烘焙光照贴图，好吧~~

很简单 其实就是下面的一个pass：

Pass {
        Tags { "LightMode" = "VertexLMRGBM" }
        
        Lighting Off
        BindChannels {
            Bind "Vertex", vertex
            Bind "texcoord1", texcoord0 // lightmap uses 2nd uv
            Bind "texcoord", texcoord1 // main uses 1st uv
        }
        
        SetTexture [unity_Lightmap] {
            matrix [unity_LightmapMatrix]
            combine texture * texture alpha DOUBLE
        }
        SetTexture [_MainTex] {
            combine texture * previous QUAD, texture * primary
        }
    }    

------5.0--------------------------------------------------------------------------------------------------------我就是懒你怎么着------------------------------------------------------------------------------------------------

Pass {
Tags { "LightMode" = "VertexLM" }

Lighting Off
BindChannels {
Bind "Vertex", vertex
Bind "texcoord1", texcoord0 // lightmap uses 2nd uv
Bind "texcoord", texcoord1 // main uses 1st uv
}

SetTexture [unity_Lightmap] {
matrix [unity_LightmapMatrix]
combine texture
}
SetTexture [_MainTex] {
constantColor (1,1,1,1)
combine texture * previous DOUBLE, constant // UNITY_OPAQUE_ALPHA_FFP
}
}