Unity ShadowCast

Pass{    Name "ShadowCaster"    Tags { "LightMode" = "ShadowCaster" }        Fog { Mode Off }     ZWrite On ZTest Less Cull Off     Offset 1,1     CGPROGRAM#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;float4 frag (v2f i) : COLOR {fixed4 texcol = tex2D(_MainTex, i.uv);clip(texcol.a - _Cutoff);SHADOW_CASTER_FRAGMENT(i)}ENDCG}