Unity shader学习之Alpha Test的阴影

Alpha Test的阴影，

shader如下：

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/Alpha Test Shadow"
{
    Properties
    {
        _Color ("Main Color", Color) = (1,1,1,1)          // 必需
        _MainTex("Main Texture", 2D) = "white" {}
        _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5        // 必需
    }

    SubShader
    {
        Tags
        {
            "Queue" = "AlphaTest"
            "RenderType" = "TransparentCutout"
        }

        Pass
        {
            Tags
            {
                "LightMode" = "ForwardBase"
            }
            Cull Off                                    // 背面

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_fwdbase

            #include "UnityCG.cginc"
            #include "Lighting.cginc"
            #include "AutoLight.cginc"

            float4 _Color;
            sampler2D _MainTex;
            float _Cutoff;

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                float3 normal : NORMAL;
            };

            struct v2f
            {
                float4 pos : SV_POSITION;
                float2 uv : TEXCOORD0;
                float3 worldNormal : TEXCOORD1;
                float3 worldPos : TEXCOORD2;
                SHADOW_COORDS(3)
            };

            v2f vert(appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                o.worldNormal = UnityObjectToWorldNormal(v.normal);
                o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
                TRANSFER_SHADOW(o);
                return o;
            }

            fixed4 frag(v2f i) : SV_TARGET
            {
                fixed4 albedo = tex2D(_MainTex, i.uv) * _Color;

                clip(albedo.a - _Cutoff);

                fixed3 ambient = albedo.rgb * UNITY_LIGHTMODEL_AMBIENT.rgb;

                float3 worldLight = UnityWorldSpaceLightDir(i.worldPos);
                fixed3 diff = albedo.rgb * _LightColor0.rgb * max(0, dot(i.worldNormal, worldLight));

                UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);

                fixed3 col = ambient + diff * atten;

                return fixed4(col, 1);
            }

            ENDCG
        }
    }

    Fallback "Transparent/Cutout/VertexLit"                    // 必需，阴影投射pass
}

效果如下：