Geometry clipping shader

SpatialCutoffTest.shader

Shader "Mine/Spatial Cutoff Test"
{
	Properties
	{
		_Color ("Main Color", Color) = (1,1,1,1)
		_MainTex ("Base (RGB)", 2D) = "white" {}
		_Cutoff ("Cutoff", Float) = 1
	}

	SubShader
	{
		Pass
		{

CGPROGRAM
#pragma exclude_renderers xbox360
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_fog_exp2
#include "UnityCG.cginc"

float4 _Color;
sampler2D _MainTex;
float _Cutoff;

struct v2f
{
	float4 pos : SV_POSITION;
	float2 uv : TEXCOORD0;
	float4 newPos;
};

v2f vert(appdata_base v)
{
	v2f o;
	o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
	o.uv = TRANSFORM_UV(0);
	o.newPos = mul(UNITY_MATRIX_P, v.vertex);
	return o;
}

half4 frag(v2f i) : COLOR
{
	half4 texcol = tex2D(_MainTex, i.uv);

	if(i.newPos[2] > _Cutoff)
		discard;

	return texcol * _Color;
}
ENDCG

		}
	} 

	FallBack "VertexLit"
}