在Unity 5上使用Unlit着色器投射阴影？

Question

我试图从Unlit Cutout shader投射阴影。我真的不知道该怎么做。我尝试将阴影施法者部分复制出标准着色器并进行编译，但它不会投射阴影。以下是我到目前为止的情况：

// Unlit alpha-cutout shader.
// - no lighting
// - no lightmap support
// - no per-material color

Shader "Unlit/Transparent Cutout Shadow" {
Properties {
    _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
}
SubShader {
Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
LOD 100

Pass {  
    CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        #pragma multi_compile_fog

        #include "UnityCG.cginc"

        struct appdata_t {
            float4 vertex : POSITION;
            float2 texcoord : TEXCOORD0;
        };

        struct v2f {
            float4 vertex : SV_POSITION;
            fixed4 color    : COLOR;
            half2 texcoord : TEXCOORD0;
            UNITY_FOG_COORDS(1)
        };

        sampler2D _MainTex;
        float4 _MainTex_ST;
        fixed _Cutoff;

        v2f vert (appdata_full v)
        {
            v2f o;
            o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
            o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
            UNITY_TRANSFER_FOG(o,o.vertex);
            o.color = v.color;
            return o;
        }

        fixed4 frag (v2f i) : SV_Target
        {
            fixed4 col = tex2D(_MainTex, i.texcoord);
            clip(col.a - _Cutoff);
            UNITY_APPLY_FOG(i.fogCoord, col);
            return col * i.color;
        }
    ENDCG
}

Pass {
    Name "ShadowCaster"
    Tags { "LightMode" = "ShadowCaster" }

    ZWrite On ZTest LEqual

    CGPROGRAM
    #pragma target 3.0
    // TEMPORARY: GLES2.0 temporarily disabled to prevent errors spam on devices without textureCubeLodEXT
    #pragma exclude_renderers gles

    // -------------------------------------


    #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
    #pragma multi_compile_shadowcaster

    #pragma vertex vertShadowCaster
    #pragma fragment fragShadowCaster

    #include "UnityStandardShadow.cginc"

    ENDCG
}


// ------------------------------------------------------------------
//  Shadow rendering pass
Pass {
    Name "ShadowCaster"
    Tags { "LightMode" = "ShadowCaster" }

    ZWrite On ZTest LEqual

    CGPROGRAM
    #pragma target 2.0

    #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
    #pragma skip_variants SHADOWS_SOFT
    #pragma multi_compile_shadowcaster

    #pragma vertex vertShadowCaster
    #pragma fragment fragShadowCaster

    #include "UnityStandardShadow.cginc"

    ENDCG
}

}

}